Mobile augmented reality survey: a bottom-up approach
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paper_title: Mobile Collaborative Augmented Reality: the Augmented Stroll

paper_content:

The paper focuses on Augmented Reality systems in which interaction with the real world is augmented by the computer, the task being performed in the real world. We first define what mobile AR systems, collaborative AR systems and finally mobile and collaborative AR systems are. We then present the augmented stroll and its software design as one example of a mobile and collaborative AR system. The augmented stroll is applied to Archaeology in the MAGIC (Mobile Augmented Group Interaction in Context) project.
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paper_title: Recent Advances in Augmented Reality

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In 1997, Azuma published a survey on augmented reality (AR). Our goal is to complement, rather than replace, the original survey by presenting representative examples of the new advances. We refer one to the original survey for descriptions of potential applications (such as medical visualization, maintenance and repair of complex equipment, annotation, and path planning); summaries of AR system characteristics (such as the advantages and disadvantages of optical and video approaches to blending virtual and real, problems in display focus and contrast, and system portability); and an introduction to the crucial problem of registration, including sources of registration error and error-reduction strategies.
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paper_title: Designing backpacks for high fidelity mobile outdoor augmented reality

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This paper presents the design for our latest backpack to support mobile outdoor augmented reality, and how it evolved from lessons learned with our previous designs. We present a number of novel features which help to reduce size and weight, improve reliability and ease of configuration, and reduce CPU usage on laptop computers.
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paper_title: Structured visual markers for indoor pathfinding

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We present a mobile augmented reality (AR) system to guide a user through an unfamiliar building to a destination room. The system presents a world-registered wireframe model of the building labeled with directional information in a see-through heads-up display, and a three-dimensional world-in-miniature (WIM) map on a wrist-worn pad that also acts as an input device. Tracking is done using a combination of wall-mounted ARToolkit markers observed by a head-mounted camera, and an inertial tracker. To allow coverage of arbitrarily large areas with a limited set of markers, a structured marker re-use scheme based on graph coloring has been developed.
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paper_title: Human pacman: A mobile entertainment system with ubiquitous computing and tangible interaction over a wide outdoor area

paper_content:

Human Pacman is an interactive role-playing game that envisions to bring the computer gaming experience to a new level of emotional and sensory gratification by setting the real world as a playground. This is a physical fantasy game integrated with human-social and mobile-gaming that emphasizes on collaboration and competition between players. By setting the game in a wide outdoor area, natural human-physical movements have become an integral part of the game. Pacmen and Ghosts are now human players in the real world experiencing mixed reality visualization from the wearable computers on them. Virtual cookies and actual physical objects are incorporated to provide novel experiences of seamless transitions between real and virtual worlds and tangible human computer interface respectively. We believe Human Pacman is pioneering a new form of gaming that anchors on physicality, mobility, social interaction, and ubiquitous computing.
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paper_title: TimeWarp: interactive time travel with a mobile Mixed Reality game

paper_content:

Mobile location-aware applications have become quite popular across a range of new areas such as pervasive games and mobile edutainment applications. However it is only recently, that approaches have been presented which combine gaming and education with mobile Augmented Reality systems. However they typically lack a close crossmedia integration of the surroundings, and often annotate or extend the environment rather than modifying and altering it. In this paper we present a mobile outdoor mixed reality game for exploring the history of a city in the spatial and the temporal dimension. We introduce the design and concept of the game and present a universal mechanism to define and setup multi-modal user interfaces for the game challenges. Finally we discuss the results of the user tests.
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paper_title: Going out: robust model-based tracking for outdoor augmented reality

paper_content:

This paper presents a model-based hybrid tracking system for outdoor augmented reality in urban environments enabling accurate, realtime overlays for a handheld device. The system combines several well-known approaches to provide a robust experience that surpasses each of the individual components alone: an edge-based tracker for accurate localisation, gyroscope measurements to deal with fast motions, measurements of gravity and magnetic field to avoid drift, and a back store of reference frames with online frame selection to re-initialize automatically after dynamic occlusions or failures. A novel edge-based tracker dispenses with the conventional edge model, and uses instead a coarse, but textured, 3D model. This yields several advantages: scale-based detail culling is automatic, appearance-based edge signatures can be used to improve matching and the models needed are more commonly available. The accuracy and robustness of the resulting system is demonstrated with comparisons to map-based ground truth data.
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paper_title: Scan and Tilt – Towards Natural Interaction for Mobile Museum Guides

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This paper presents a new interaction technique - scan and tilt - aiming to enable a more natural interaction with mobile museum guides. Our work combines multiple modalities - gestures, physical selection, location, graphical and voice. In particular, physical selection is obtained by scanning RFID tags associated with the artworks, and tilt gestures are used to control and navigate the user interface and multimedia information. We report on how it has been applied to a mobile museum guide in order to enhance the user experience, providing details on a first user test carried out on our prototype.
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paper_title: Ubiquitous animated agents for augmented reality

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Most of today's Augmented Reality (AR) systems operate as passive information browsers relying on a finite and deterministic world model and a predefined hardware and software infrastructure. We propose an AR framework that dynamically and proactively exploits hitherto unknown applications and hardware devices, and adapts the appearance of the user interface to persistently stored and accumulated user preferences. Our framework explores proactive computing, multi-user interface adaptation, and user interface migration. We employ mobile and autonomous agents embodied by real and virtual objects as an interface and interaction metaphor, where agent bodies are able to opportunistically migrate between multiple AR applications and computing platforms to best match the needs of the current application context. We present two pilot applications to illustrate design concepts.
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paper_title: ARToolKit on the PocketPC platform

paper_content:

In this paper, we describe the port of ARToolKit onto the PocketPC platform including optimizations that led to a three-fold speedup over the native cross-compiled version. The ported ARToolKit module was successfully used in the Handheld AR project.
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paper_title: Towards Massively Multi-user Augmented Reality on Handheld Devices

paper_content:

Augmented Reality (AR) can naturally complement mobile computing on wearable devices by providing an intuitive interface to a three-dimensional information space embedded within physical reality. Unfortunately, current wearable AR systems are relatively complex, expensive, fragile and heavy, rendering them unfit for large-scale deployment involving untrained users outside constrained laboratory environments. Consequently, the scale of collaborative multi-user experiments have not yet exceeded a handful of participants. In this paper, we present a system architecture for interactive, infrastructure-independent multi-user AR applications running on off-the-shelf handheld devices. We implemented a four-user interactive game installation as an evaluation setup to encourage playful engagement of participants in a cooperative task. Over the course of five weeks, more than five thousand visitors from a wide range of professional and socio-demographic backgrounds interacted with our system at four different locations.
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paper_title: Mobile augmented reality interaction techniques for authoring situated media on-site

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We present a set of mobile augmented reality interaction techniques for authoring situated media: multimedia and hypermedia that are embedded within the physical environment. Our techniques are designed for use with a tracked hand-held tablet display with an attached camera, and rely on "freezing" the frame for later editing.
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paper_title: Generic Interaction Techniques for Mobile Collaborative Mixed Systems

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The main characteristic of a mobile collaborative mixed system is that augmentation of the physical environment of one user occurs through available knowledge of where the user is and what the other users are doing. Links between the physical and digital worlds are no longer static but dynamically defined by users to create a collaborative augmented environment. In this article we present generic interaction techniques for smoothly combining the physical and digital worlds of a mobile user in the context of a collaborative situation. We illustrate the generic nature of the techniques with two systems that we developed: MAGIC for archaeological fieldwork and TROC a mobile collaborative game.
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paper_title: EyeGuardian: a framework of eye tracking and blink detection for mobile device users

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Computer Vision Syndrome (CVS) is a common problem in the "Information Age", and it is becoming more serious as mobile devices (e.g. smartphones and tablet PCs) with small, low-resolution screens are outnumbering the home computers. The simplest way to avoid CVS is to blink frequently. However, most people do not realize that they blink less and some do not blink at all in front of the screen. In this paper, we present a mobile application that keeps track of the reader's blink rate and prods the user to blink if an exceptionally low blink rate is detected. The proposed eye detection and tracking algorithm is designed for mobile devices and can keep track of the eyes in spite of camera motion. The main idea is to predict the eye position in the camera frame using the feedback from the built-in accelerometer. The eye tracking system was built on a commercial Tablet PC. The experimental results consistently show that the scheme can withstand very aggressive mobility scenarios.
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paper_title: A Mixed Reality Approach for Merging Abstract and Concrete Knowledge

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Mixed reality's (MR) ability to merge real and virtual spaces is applied to merging different knowledge types, such as abstract and concrete knowledge. To evaluate whether the merging of knowledge types can benefit learning, MR was applied to an interesting problem in anesthesia machine education. The virtual anesthesia machine (VAM) is an interactive, abstract 2D transparent reality simulation of the internal components and invisible gas flows of an anesthesia machine. It is widely used in anesthesia education. However when presented with an anesthesia machine, some students have difficulty transferring abstract VAM knowledge to the concrete real device. This paper presents the augmented anesthesia machine (AAM). The AAM applies a magic-lens approach to combine the VAM simulation and a real anesthesia machine. The AAM allows students to interact with the real anesthesia machine while visualizing how these interactions affect the internal components and invisible gas flows in the real world context. To evaluate the AAM's learning benefits, a user study was conducted. Twenty participants were divided into either the VAM (abstract only) or AAM (concrete+abstract) conditions. The results of the study show that MR can help users bridge their abstract and concrete knowledge, thereby improving their knowledge transfer into real world domains.
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paper_title: Towards Massively Multi-user Augmented Reality on Handheld Devices

paper_content:

Augmented Reality (AR) can naturally complement mobile computing on wearable devices by providing an intuitive interface to a three-dimensional information space embedded within physical reality. Unfortunately, current wearable AR systems are relatively complex, expensive, fragile and heavy, rendering them unfit for large-scale deployment involving untrained users outside constrained laboratory environments. Consequently, the scale of collaborative multi-user experiments have not yet exceeded a handful of participants. In this paper, we present a system architecture for interactive, infrastructure-independent multi-user AR applications running on off-the-shelf handheld devices. We implemented a four-user interactive game installation as an evaluation setup to encourage playful engagement of participants in a cooperative task. Over the course of five weeks, more than five thousand visitors from a wide range of professional and socio-demographic backgrounds interacted with our system at four different locations.
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paper_title: An Augmented Reality Presentation System for Remote Cultural Heritage Sites

paper_content:

Museums often lack the possibility to present archaeological or cultural heritage sites in a realistic and interesting way. Thus are proposing a new way to show augmented reality applications of cultural heritage sites at remote places like museums. In the exhibition space large wall-filling photographs of the real site are superimposed with interactive contextual annotations like 3D reconstructions, images and movies. Therefore we are using two different hardware setups for visualization: Standard UMPCs and a custom made revolving display. The setup has been installed and tested at SIGGRAPH 2008, Allard Pierson Museum in Amsterdam and CeBIT 2009. Museum visitors could experience Forum Romanum and Satricum in an informative and intuitive way by pointing the video see through devices on different areas of the photographs. The result is a more realistic and entertaining way for presenting cultural heritage sites in museums. Furthermore our solution is less expensive than comparable installations regarding content and hardware.
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paper_title: Wide Area Tracking Tools for Augmented Reality

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We have developed a hand-held augmented reality platform exploiting a combination of multiple sensors built around an ultra-wideband tracking system. We demonstrate two applications illustrating how an environment exploiting this platform can be set up. Firstly, a technician-support application provides intuitive in-situ instructions on how a wide area tracking system should be configured. The use of 3D registered graphics greatly assists in the debugging of common awkward use cases involving reflections off metal surfaces. Secondly, a navigation application utilises this newly configured and calibrated tracker, as well as other sensors, adapting to whatever is available in a given locale.
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paper_title: SeeMon: scalable and energy-efficient context monitoring framework for sensor-rich mobile environments

paper_content:

Proactively providing services to mobile individuals is essential for emerging ubiquitous applications. The major challenge in providing users with proactive services lies in continuously monitoring their contexts based on numerous sensors. The context monitoring with rich sensors imposes heavy workloads on mobile devices with limited computing and battery power. We present SeeMon, a scalable and energy-efficient context monitoring framework for sensor-rich, resource-limited mobile environments. Running on a personal mobile device, SeeMon effectively performs context monitoring involving numerous sensors and applications. On top of SeeMon, multiple applications on the device can proactively understand users' contexts and react appropriately. This paper proposes a novel context monitoring approach that provides efficient processing and sensor control mechanisms. We implement and test a prototype system on two mobile devices: a UMPC and a wearable device with a diverse set of sensors. Example applications are also developed based on the implemented system. Experimental results show that SeeMon achieves a high level of scalability and energy efficiency.
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paper_title: Outdoors augmented reality on mobile phone using loxel-based visual feature organization

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We have built an outdoors augmented reality system for mobile phones that matches camera-phone images against a large database of location-tagged images using a robust image retrieval algorithm. We avoid network latency by implementing the algorithm on the phone and deliver excellent performance by adapting a state-of-the-art image retrieval algorithm based on robust local descriptors. Matching is performed against a database of highly relevant features, which is continuously updated to reflect changes in the environment. We achieve fast updates and scalability by pruning of irrelevant features based on proximity to the user. By compressing and incrementally updating the features stored on the phone we make the system amenable to low-bandwidth wireless connections. We demonstrate system robustness on a dataset of location-tagged images and show a smart-phone implementation that achieves a high image matching rate while operating in near real-time.
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paper_title: An Augmented Reality Presentation System for Remote Cultural Heritage Sites

paper_content:

Museums often lack the possibility to present archaeological or cultural heritage sites in a realistic and interesting way. Thus are proposing a new way to show augmented reality applications of cultural heritage sites at remote places like museums. In the exhibition space large wall-filling photographs of the real site are superimposed with interactive contextual annotations like 3D reconstructions, images and movies. Therefore we are using two different hardware setups for visualization: Standard UMPCs and a custom made revolving display. The setup has been installed and tested at SIGGRAPH 2008, Allard Pierson Museum in Amsterdam and CeBIT 2009. Museum visitors could experience Forum Romanum and Satricum in an informative and intuitive way by pointing the video see through devices on different areas of the photographs. The result is a more realistic and entertaining way for presenting cultural heritage sites in museums. Furthermore our solution is less expensive than comparable installations regarding content and hardware.
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paper_title: Sketching up the world: in situ authoring for mobile Augmented Reality

paper_content:

We present a novel system allowing in situ content creation for mobile Augmented Reality in unprepared environments. This system targets smartphones and therefore allows a spontaneous authoring while in place. We describe two different scenarios, which are depending on the size of the working environment and consequently use different tracking techniques. A natural feature-based approach for planar targets is used for small working spaces whereas for larger working environments, such as in outdoor scenarios, a panoramic-based orientation tracking is deployed. Both are integrated into one system allowing the user to use the same interaction for creating the content applying a set of simple, yet powerful modeling functions for content creation. The resulting content for Augmented Reality can be shared with other users using a dedicated content server or kept in a private inventory for later use.
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paper_title: Location based Applications for Mobile Augmented Reality

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In this work we investigate building indoor location based applications for a mobile augmented reality system. We believe that augmented reality is a natural interface to visualize spacial information such as position or direction of locations and objects for location based applications that process and present information based on the user's position in the real world. To enable such applications we construct an indoor tracking system that covers a substantial part of a building. It is based on visual tracking of fiducial markers enhanced with an inertial sensor for fast rotational updates. To scale such a system to a whole building we introduce a space partitioning scheme to reuse fiducial markers throughout the environment. Finally we demonstrate two location based applications built upon this facility, an indoor navigation aid and a library search application.
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paper_title: Marker-Based Embodied Interaction for Handheld Augmented Reality Games

paper_content:

JVRB, 4(2007), no. 5. - This article deals with embodied user interfaces for handheld augmented reality games, which consist of both physical and virtual components. We have developed a number of spatial interaction techniques that optically capture the device's movement and orientation relative to a ::: visual marker. Such physical interactions in 3-D space enable manipulative control of mobile games. In addition to acting as a physical controller that recognizes multiple game-dependent gestures, the mobile device augments the camera view with graphical overlays. We describe ::: three game prototypes that use ubiquitous product packaging and other passive media as backgrounds for handheld augmentation. The prototypes can be realized on widely available off-the-shelf hardware and require only minimal setup and infrastructure support.
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paper_title: Location-based augmented reality on mobile phones

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The computational capability of mobile phones has been rapidly increasing, to the point where augmented reality has become feasible on cell phones. We present an approach to indoor localization and pose estimation in order to support augmented reality applications on a mobile phone platform. Using the embedded camera, the application localizes the device in a familiar environment and determines its orientation. Once the 6 DOF pose is determined, 3D virtual objects from a database can be projected into the image and displayed for the mobile user. Off-line data acquisition consists of acquiring images at different locations in the environment. The online pose estimation is done by a feature-based matching between the cell phone image and an image selected from the precomputed database using the phone's sensors (accelerometer and magnetometer). The application enables the user both to visualize virtual objects in the camera image and to localize the user in a familiar environment. We describe in detail the process of building the database and the pose estimation algorithm used on the mobile phone. We evaluate the algorithm performance as well as its accuracy in terms of reprojection distance of the 3D virtual objects in the cell phone image.
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paper_title: Combination of UWB and GPS for indoor-outdoor vehicle localization

paper_content:

GPS receivers are satellite-based devices widely used for vehicle localization that, given their limitations, are not suitable for performing within indoor or dense urban environments. On the other hand ultra-wide band (UWB), a technology used for efficient wireless communication, has recently being used for vehicle localization in indoor environments with promising results. This paper focuses on the combination of both technologies for accurate positioning of vehicles in a mixed scenario (both indoor and outdoor situations), which is typical in some industrial applications. Our approach is based on combining sensor information in a Monte Carlo localization algorithm (also known as particle Filter), which has revealed its suitability for probabilistically coping with a variety of sensory data. The performance of our approach has been satisfactorily tested on a real robot, endowed with a UWB master antenna and a GPS receiver, within an indoor-outdoor scenario where three UWB slave antennas were placed in the indoor area.
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paper_title: Sensor fusion and occlusion refinement for tablet-based AR

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This paper presents a set of technologies which enable robust, accurate, high resolution augmentation of live video, delivered via a tablet PC to which a video camera has been attached. By combining several technologies, this is achieved without the use of contrived markers in the environment: An outside-in tracker observes the tablet to generate robust, low-accuracy pose estimates. An inside-out tracker running on the tablet observes the video feed from the tablet-mounted camera and provides high-accuracy pose estimates by tracking natural features in the environment. Information from both of these trackers is combined in an extended Kalman filter. Finally, to maximise the quality of the augmented imagery, boundaries where the real world occludes the virtual imagery are identified and another tracker is used to refine the boundaries between real and virtual imagery so that their synthesis is as convincing as possible.
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paper_title: UMAR: Ubiquitous Mobile Augmented Reality

paper_content:

In this paper we discuss the prospects of using marker based Augmented Reality for context aware applications on mobile phones. We also present the UMAR, a conceptual framework for developing Ubiquitous Mobile Augmented Reality applications which consists of research areas identified as relevant for successfully bridging the physical world and the digital domain using Mobile Augmented Reality. A step towards this we have successfully ported the ARToolkit to consumer mobile phones running on the Symbian platform and present results around this. We also present three sample applications based on UMAR and future case study work planned.
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paper_title: ARToolKit on the PocketPC platform

paper_content:

In this paper, we describe the port of ARToolKit onto the PocketPC platform including optimizations that led to a three-fold speedup over the native cross-compiled version. The ported ARToolKit module was successfully used in the Handheld AR project.
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paper_title: Collaborative use of mobile augmented reality with paper maps

paper_content:

The popularity of augmented reality (AR) applications on mobile devices is increasing, but there is as yet little research on their use in real-settings. We review data from two pioneering field trials where MapLens, a magic lens that augments paper-based city maps, was used in small-group collaborative tasks. The first study compared MapLens to a digital version akin to Google Maps, the second looked at using one shared mobile device vs. using multiple devices. The studies find place-making and use of artefacts to communicate and establish common ground as predominant modes of interaction in AR-mediated collaboration with users working on tasks together despite not needing to.
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paper_title: Like bees around the hive: a comparative study of a mobile augmented reality map

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We present findings from field trials of MapLens, a mobile augmented reality (AR) map using a magic lens over a paper map. Twenty-six participants used MapLens to play a location-based game in a city centre. Comparisons to a group of 11 users with a standard 2D mobile map uncover phenomena that arise uniquely when interacting with AR features in the wild. The main finding is that AR features facilitate place-making by creating a constant need for referencing to the physical, and in that it allows for ease of bodily configurations for the group, encourages establishment of common ground, and thereby invites discussion, negotiation and public problem-solving. The main potential of AR maps lies in their use as a collaborative tool.
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paper_title: Video see-through AR on consumer cell-phones

paper_content:

We present a first running video see-through augmented reality system on a consumer cell-phone. It supports the detection and differentiation of different markers, and correct integration of rendered 3D graphics into the live video stream via a weak perspective projection camera model and an OpenGL rendering pipeline.
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paper_title: “Studierstube”: An environment for collaboration in augmented reality

paper_content:

We propose an architecture for multi-user augmented reality with applications in visualisation, presentation and education, which we call "Studierstube". Our system presents three-dimensional stereoscopic graphics simultaneously to a group of users wearing light weight see-through head mounted displays. The displays do not affect natural communication and interaction, making working together very effective. Users see the same spatially aligned model, but can independently control their viewpoint and different layers of the data to be displayed. The setup serves computer supported cooperative work and enhances cooperation of visualisation experts. This paper presents the client-server software architecture underlying this system and details that must be addressed to create a high-quality augmented reality setup.
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paper_title: Nexus - an open global infrastructure for spatial-aware applications

paper_content:

Due to the lack of a generic platform for location- and spatial-aware systems, many basic services have to be reimplemented in each application that uses spatial-awareness. A cooperation among different applications is also difficult to achieve without a common platform. In this paper we present a platform that solves these problems. It provides an infrastructure that is based on computer models of regions of the physical world, which are augmented by virtual objects. We show how virtual objects make the integration of existing information systems and services in spatial-aware systems easier. Furthermore, our platform supports interactions between the computer models and the real world and integrates single models in a global 'Augmented World'.
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paper_title: Marker tracking and HMD calibration for a video-based augmented reality conferencing system

paper_content:

We describe an augmented reality conferencing system which uses the overlay of virtual images on the real world. Remote collaborators are represented on virtual monitors which can be freely positioned about a user in space. Users can collaboratively view and interact with virtual objects using a shared virtual whiteboard. This is possible through precise virtual image registration using fast and accurate computer vision techniques and head mounted display (HMD) calibration. We propose a method for tracking fiducial markers and a calibration method for optical see-through HMD based on the marker tracking.
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paper_title: UMAR: Ubiquitous Mobile Augmented Reality

paper_content:

In this paper we discuss the prospects of using marker based Augmented Reality for context aware applications on mobile phones. We also present the UMAR, a conceptual framework for developing Ubiquitous Mobile Augmented Reality applications which consists of research areas identified as relevant for successfully bridging the physical world and the digital domain using Mobile Augmented Reality. A step towards this we have successfully ported the ARToolkit to consumer mobile phones running on the Symbian platform and present results around this. We also present three sample applications based on UMAR and future case study work planned.
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paper_title: InfoSPOT: A mobile Augmented Reality method for accessing building information through a situation awareness approach

paper_content:

article i nfo Article history: Accepted 9 September 2012 Available online 6 October 2012 The Architecture, Engineering, Construction, and Owner/Operator (AECO) industry is constantly searching for new methods for increasing efficiency and productivity. Facility Managers (FMs), as a part of the owner/ operator role, work in complex and dynamic environments where critical decisions are constantly made. This decision-making process and its consequent performance can be improved by enhancing Situation Awareness (SA) of the FMs through new digital technologies. In this paper, InfoSPOT (Information Surveyed Point for Observation and Tracking), is recommended to FMs as a mobile Augmented Reality (AR) tool for accessing information about the facilities they maintain. AR has been considered as a viable option to reduce inefficiencies of data overload by providing FMs with a SA-based tool for visualizing their "real-world" envi- ronment with added interactive data. A prototype of the AR application was developed and a user participa- tion experiment and analysis conducted to evaluate the features of InfoSPOT. This innovative application of AR has the potential to improve construction practices, and in this case, facility management. Published by Elsevier B.V.
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paper_title: Tinmith-Metro: new outdoor techniques for creating city models with an augmented reality wearable computer

paper_content:

This paper presents new techniques for capturing and viewing on site 3D graphical models for large outdoor objects. Using an augmented reality wearable computer, we have developed a software system, known as Tinmith-Metro. Tinmith-Metro allows users to control a 3D constructive solid geometry modeller for building graphical objects of large physical artefacts, for example buildings, in the physical world. The 3D modeller is driven by a new user interface known as Tinmith-Hand, which allows the user to control the modeller using a set of pinch gloves and hand tracking. These techniques allow user to supply their AR renderers with models that would previously have to be captured with manual, time-consuming, and/or expensive methods.
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paper_title: KHARMA: An open KML/HTML architecture for mobile augmented reality applications

paper_content:

Widespread future adoption of augmented reality technology will rely on a broadly accessible standard for authoring and distributing content with, at a minimum, the flexibility and interactivity provided by current web authoring technologies. We introduce KHARMA, an open architecture based on KML for geospatial and relative referencing combined with HTML, JavaScript and CSS technologies for content development and delivery. This architecture uses lightweight representations that decouple infrastructure and tracking sources from authoring and content delivery. Our main contribution is a re-conceptualization of KML that turns HTML content formerly confined to balloons into first-class elements in the scene. We introduce the KARML extension that gives authors increase control over the presentation of HTML content and its spatial relationship to other content.
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paper_title: Design of a component-based augmented reality framework

paper_content:

The authors propose a new approach to building augmented reality (AR) systems using a component-based software framework. This has advantages for all parties involved with AR systems. A project manager can reuse existing components in new applications; an end user can reconfigure his system by plugging modules together, an application developer can view the system at a high level of abstraction; and a component developer can focus on technical problems. Our proposed framework consists of reusable distributed services for key subproblems of AR, the middleware to combine them, and an extensible software architecture. We have implemented services for tracking, modeling real and virtual objects, modeling structured navigation or maintenance instructions, and multimodal user interfaces. As a working proof of our concept, we have built an indoor and outdoor campus navigation system using different modes of tracking and user interaction.
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paper_title: Mobile Collaborative Augmented Reality: the Augmented Stroll

paper_content:

The paper focuses on Augmented Reality systems in which interaction with the real world is augmented by the computer, the task being performed in the real world. We first define what mobile AR systems, collaborative AR systems and finally mobile and collaborative AR systems are. We then present the augmented stroll and its software design as one example of a mobile and collaborative AR system. The augmented stroll is applied to Archaeology in the MAGIC (Mobile Augmented Group Interaction in Context) project.
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paper_title: Data Management Strategies for Mobile Augmented Reality

paper_content:

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.
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paper_title: Facilitating Collaboration with Laser Projector-Based Spatial Augmented Reality in Industrial Applications

paper_content:

Spatial Augmented Reality (SAR) superimposes computer generated virtual objects directly on physical objects’ surfaces. This enables user to interact with real world objects in a natural manner. This chapter investigates SAR techniques and summarizes advantages with the difficulties of SAR in presenting digital information to users. The chapter then presents a concept of portable collaborative SAR. The concept utilizes both projector-based SAR and Head-Mounted-Display (HMD) based Augmented Reality (AR) in a single environment to assist collaborations within multiple users. The concept combines advantages of both projector-based SAR for collaboration and HMD-based AR display in personalization to improve the efficiency of collaborative tasks. The presented concept is explored in a case study of industrial quality assurance scenario to show its effectiveness.
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paper_title: Map torchlight: a mobile augmented reality camera projector unit

paper_content:

The advantages of paper-based maps have been utilized in the field of mobile Augmented Reality (AR) in the last few years. Traditional paper-based maps provide high-resolution, large-scale information with zero power consumption. There are numerous implementations of magic lens interfaces that combine high-resolution paper maps with dynamic handheld displays. From an HCI perspective, the main challenge of magic lens interfaces is that users have to switch their attention between the magic lens and the information in the background. In this paper, we attempt to overcome this problem by using a lightweight mobile camera projector unit to augment the paper map directly with additional information. The "Map Torchlight" is tracked over a paper map and can precisely highlight points of interest, streets, and areas to give directions or other guidance for interacting with the map.
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paper_title: Human pacman: A mobile entertainment system with ubiquitous computing and tangible interaction over a wide outdoor area

paper_content:

Human Pacman is an interactive role-playing game that envisions to bring the computer gaming experience to a new level of emotional and sensory gratification by setting the real world as a playground. This is a physical fantasy game integrated with human-social and mobile-gaming that emphasizes on collaboration and competition between players. By setting the game in a wide outdoor area, natural human-physical movements have become an integral part of the game. Pacmen and Ghosts are now human players in the real world experiencing mixed reality visualization from the wearable computers on them. Virtual cookies and actual physical objects are incorporated to provide novel experiences of seamless transitions between real and virtual worlds and tangible human computer interface respectively. We believe Human Pacman is pioneering a new form of gaming that anchors on physicality, mobility, social interaction, and ubiquitous computing.
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paper_title: Video see-through AR on consumer cell-phones

paper_content:

We present a first running video see-through augmented reality system on a consumer cell-phone. It supports the detection and differentiation of different markers, and correct integration of rendered 3D graphics into the live video stream via a weak perspective projection camera model and an OpenGL rendering pipeline.
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paper_title: Facilitating Collaboration with Laser Projector-Based Spatial Augmented Reality in Industrial Applications

paper_content:

Spatial Augmented Reality (SAR) superimposes computer generated virtual objects directly on physical objects’ surfaces. This enables user to interact with real world objects in a natural manner. This chapter investigates SAR techniques and summarizes advantages with the difficulties of SAR in presenting digital information to users. The chapter then presents a concept of portable collaborative SAR. The concept utilizes both projector-based SAR and Head-Mounted-Display (HMD) based Augmented Reality (AR) in a single environment to assist collaborations within multiple users. The concept combines advantages of both projector-based SAR for collaboration and HMD-based AR display in personalization to improve the efficiency of collaborative tasks. The presented concept is explored in a case study of industrial quality assurance scenario to show its effectiveness.
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paper_title: Map torchlight: a mobile augmented reality camera projector unit

paper_content:

The advantages of paper-based maps have been utilized in the field of mobile Augmented Reality (AR) in the last few years. Traditional paper-based maps provide high-resolution, large-scale information with zero power consumption. There are numerous implementations of magic lens interfaces that combine high-resolution paper maps with dynamic handheld displays. From an HCI perspective, the main challenge of magic lens interfaces is that users have to switch their attention between the magic lens and the information in the background. In this paper, we attempt to overcome this problem by using a lightweight mobile camera projector unit to augment the paper map directly with additional information. The "Map Torchlight" is tracked over a paper map and can precisely highlight points of interest, streets, and areas to give directions or other guidance for interacting with the map.
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paper_title: Combination of UWB and GPS for indoor-outdoor vehicle localization

paper_content:

GPS receivers are satellite-based devices widely used for vehicle localization that, given their limitations, are not suitable for performing within indoor or dense urban environments. On the other hand ultra-wide band (UWB), a technology used for efficient wireless communication, has recently being used for vehicle localization in indoor environments with promising results. This paper focuses on the combination of both technologies for accurate positioning of vehicles in a mixed scenario (both indoor and outdoor situations), which is typical in some industrial applications. Our approach is based on combining sensor information in a Monte Carlo localization algorithm (also known as particle Filter), which has revealed its suitability for probabilistically coping with a variety of sensory data. The performance of our approach has been satisfactorily tested on a real robot, endowed with a UWB master antenna and a GPS receiver, within an indoor-outdoor scenario where three UWB slave antennas were placed in the indoor area.
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paper_title: WUW - wear Ur world: a wearable gestural interface

paper_content:

Information is traditionally confined to paper or digitally to a screen. In this paper, we introduce WUW, a wearable gestural interface, which attempts to bring information out into the tangible world. By using a tiny projector and a camera mounted on a hat or coupled in a pendant like wearable device, WUW sees what the user sees and visually augments surfaces or physical objects the user is interacting with. WUW projects information onto surfaces, walls, and physical objects around us, and lets the user interact with the projected information through natural hand gestures, arm movements or interaction with the object itself.
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paper_title: Aided eyes: eye activity sensing for daily life

paper_content:

Our eyes collect a considerable amount of information when we use them to look at objects. In particular, eye movement allows us to gaze at an object and shows our level of interest in the object. In this research, we propose a method that involves real-time measurement of eye movement for human memory enhancement; the method employs gaze-indexed images captured using a video camera that is attached to the user's glasses. We present a prototype system with an infrared-based corneal limbus tracking method. Although the existing eye tracker systems track eye movement with high accuracy, they are not suitable for daily use because the mobility of these systems is incompatible with a high sampling rate. Our prototype has small phototransistors, infrared LEDs, and a video camera, which make it possible to attach the entire system to the glasses. Additionally, the accuracy of this method is compensated by combining image processing methods and contextual information, such as eye direction, for information extraction. We develop an information extraction system with real-time object recognition in the user's visual attention area by using the prototype of an eye tracker and a head-mounted camera. We apply this system to (1) fast object recognition by using a SURF descriptor that is limited to the gaze area and (2) descriptor matching of a past-images database. Face recognition by using haar-like object features and text logging by using OCR technology is also implemented. The combination of a low-resolution camera and a high-resolution, wide-angle camera is studied for high daily usability. The possibility of gaze-guided computer vision is discussed in this paper, as is the topic of communication by the photo transistor in the eye tracker and the development of a sensor system that has a high transparency.
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paper_title: Mobile Collaborative Augmented Reality: the Augmented Stroll

paper_content:

The paper focuses on Augmented Reality systems in which interaction with the real world is augmented by the computer, the task being performed in the real world. We first define what mobile AR systems, collaborative AR systems and finally mobile and collaborative AR systems are. We then present the augmented stroll and its software design as one example of a mobile and collaborative AR system. The augmented stroll is applied to Archaeology in the MAGIC (Mobile Augmented Group Interaction in Context) project.
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paper_title: Augmented reality in a wide area sentient environment

paper_content:

Augmented reality (AR) both exposes and supplements the user's view of the real world. Previous AR work has focussed on the close registration of real and virtual objects, which requires very accurate real-time estimates of head position and orientation. Most of these systems have been tethered and restricted to small volumes. In contrast, we have chosen to concentrate on allowing the AR user to roam freely within an entire building. At AT&T Laboratories Cambridge we provide personnel with AR services using data from an ultrasonic tracking system, called the Bat system, which has been deployed building-wide. We have approached the challenge of implementing a wide-area, in-building AR system in two different ways. The first uses a head-mounted display connected to a laptop, which combines sparse position measurements from the Bat system with more frequent rotational information from an inertial tracker to render annotations and virtual objects that relate to or coexist with the real world. The second uses a PDA to provide a convenient portal with which the user can quickly view the augmented world. These systems can be used to annotate the world in a more-or-less seamless way, allowing a richer interaction with both real and virtual objects.
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paper_title: Localization via ultra-wideband radios: a look at positioning aspects for future sensor networks

paper_content:

UWB technology provides an excellent means for wireless positioning due to its high resolution capability in the time domain. Its ability to resolve multipath components makes it possible to obtain accurate location estimates without the need for complex estimation algorithms. In this article, theoretical limits for TOA estimation and TOA-based location estimation for UWB systems have been considered. Due to the complexity of the optimal schemes, suboptimal but practical alternatives have been emphasized. Performance limits for hybrid TOA/SS and TDOA/SS schemes have also been considered. Although the fundamental mechanisms for localization, including AOA-, TOA-, TDOA-, and SS-based methods, apply to all radio air interface, some positioning techniques are favored by UWB-based systems using ultrawide bandwidths.
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paper_title: Data Management Strategies for Mobile Augmented Reality

paper_content:

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.
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paper_title: Mobile reality: A pda-based multimodal framework for synchronizing a hybrid tracking solution with 3d-graphics and location-sensitve speech interaction

paper_content:

A maintenance engineer who talks to pumps and pipes may not seem like the ideal person to entrust with keeping a factory running smoothly, but we hope that our Mobile Reality framework will enable such behavior in the future to be anything but suspicious! Described in this paper is how the Mobile Reality framework, running entirely on a Pocket PC, synchronizes a hybrid tracking solution to offer the user a seamless, location-dependent, mobile multimodal interface. The user interface juxtaposes a three-dimensional graphical view with a context-sensitive speech dialog centered upon objects located in the immediate vicinity of the mobile user. In addition, support for collaboration enables shared VRML browsing with annotation and a full-duplex voice channel.
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paper_title: Personal position measurement using dead reckoning

paper_content:

This paper compares position measurement techniquesusing dead reckoning. We are seeking to find a techniquewhich is suitable for use by pedestrians, and have compareda number of sensors that can be used to achieve a robustand accurate dead reckoning system. All our techniquesare step based. To measure steps we have compared the useof pedometers and accelerometers. To determine headingwe have compared two and three dimensional compassesand a rate gyroscope. Finally we have performed four casestudies based on real applications with standard deviationmeasured at 2.2m for a short test and 19.9m for an extendedtest. These errors can be reduced by using more computationallyexpensive filtering operations.
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paper_title: Boosting mobile GPU performance with a decoupled access/execute fragment processor

paper_content:

Smartphones represent one of the fastest growing markets, providing significant hardware/software improvements every few months. However, supporting these capabilities reduces the operating time per battery charge. The CPU/GPU component is only left with a shrinking fraction of the power budget, since most of the energy is consumed by the screen and the antenna. In this paper, we focus on improving the energy efficiency of the GPU since graphical applications consist an important part of the existing market. Moreover, the trend towards better screens will inevitably lead to a higher demand for improved graphics rendering. We show that the main bottleneck for these applications is the texture cache and that traditional techniques for hiding memory latency (prefetching, multithreading) do not work well or come at a high energy cost. We thus propose the migration of GPU designs towards the decoupled access-execute concept. Furthermore, we significantly reduce bandwidth usage in the decoupled architecture by exploiting inter-core data sharing. Using commercial Android applications, we show that the end design can achieve 93% of the performance of a heavily multithreaded GPU while providing energy savings of 34%.
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paper_title: Indoor wayfinding: developing a functional interface for individuals with cognitive impairments.

paper_content:

PURPOSE ::: Assistive technology for wayfinding will significantly improve the quality of life for many individuals with cognitive impairments. The user interface of such a system is as crucial as the underlying implementation and localisation technology. We studied the user interface of an indoor navigation system for individuals with cognitive impairments. ::: ::: ::: METHOD ::: We built a system using the Wizard-of-Oz technique that let us experiment with many guidance strategies and interface modalities. Through user studies, we evaluated various configurations of the user interface for accuracy of route completion, time to completion, and user preferences. We used a counter-balanced design that included different modalities (images, audio, and text) and different routes. ::: ::: ::: RESULTS ::: We found that although users were able to use all types of modalities to find their way indoors, they varied significantly in their preferred modalities. We also found that timing of directions requires careful attention, as does providing users with confirmation messages at appropriate times. ::: ::: ::: CONCLUSIONS ::: Our findings suggest that the ability to adapt indoor wayfinding devices for specific users' preferences and needs will be particularly important.
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paper_title: Bringing user-generated content from Internet services to mobile augmented reality clients

paper_content:

In this paper we describe a system for bringing usergenerated content to mobile augmented reality clients, taking in consideration the metadata required for visualizing it, at a sensor based tracking solution. Our proposal assumes that content is stored in multiple external Internet services, simply treated as a “cloud”, thus making the mobile client service agnostic. A prototype implementation was created for the Image Space service and the learnings of integrating with the popular Flickr service are discussed.
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paper_title: A novel interface to sensor networks using handheld augmented reality

paper_content:

Augmented Reality technology enables a mobile phone to be used as an x-ray tool, visualizing structures and states not visible to the naked eye. In this paper we evaluate a set of techniques used augmenting the world with a visualization of data from a sensor network. Combining virtual and real information introduces challenges as information from the two domains might interfere. We have applied our system to humidity data and present a user study together with feedback from domain experts. The prototype system can be seen as the first step towards a novel tool for inspection of building elements.
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paper_title: Scan and Tilt – Towards Natural Interaction for Mobile Museum Guides

paper_content:

This paper presents a new interaction technique - scan and tilt - aiming to enable a more natural interaction with mobile museum guides. Our work combines multiple modalities - gestures, physical selection, location, graphical and voice. In particular, physical selection is obtained by scanning RFID tags associated with the artworks, and tilt gestures are used to control and navigate the user interface and multimedia information. We report on how it has been applied to a mobile museum guide in order to enhance the user experience, providing details on a first user test carried out on our prototype.
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paper_title: Coarse, inexpensive, infrared tracking for wearable computing

paper_content:

We present a novel, inexpensive, coarse tracking systemthat determines a person's approximate 2D locationand 1D head orientation in an indoor environment. Whilethis coarse tracking cannot support precise registration ofoverlaid material, it can be used to drive user interfacesthat can adapt to the quality of tracking available.Our approach uses a set of strong infrared beacons,each of which broadcasts a unique ID. The beacons aredeployed in the environment such that their zones of influencestrategically overlap, partitioning the area of coverageinto a set of uniquely identifiable fragments. We use acompound, omnidirectional infrared receiver, composedof a set of individual, directional infrared receivers, toinfer 2D position (parallel to the ground plane) and 1Dorientation (azimuth), employing a Kalman-filter-basedarchitecture for smoothing and data integration withother tracking systems available. To test our ideas, wehave applied them to a prototype head tracker, and presentresults from our tests.
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paper_title: Combination of UWB and GPS for indoor-outdoor vehicle localization

paper_content:

GPS receivers are satellite-based devices widely used for vehicle localization that, given their limitations, are not suitable for performing within indoor or dense urban environments. On the other hand ultra-wide band (UWB), a technology used for efficient wireless communication, has recently being used for vehicle localization in indoor environments with promising results. This paper focuses on the combination of both technologies for accurate positioning of vehicles in a mixed scenario (both indoor and outdoor situations), which is typical in some industrial applications. Our approach is based on combining sensor information in a Monte Carlo localization algorithm (also known as particle Filter), which has revealed its suitability for probabilistically coping with a variety of sensory data. The performance of our approach has been satisfactorily tested on a real robot, endowed with a UWB master antenna and a GPS receiver, within an indoor-outdoor scenario where three UWB slave antennas were placed in the indoor area.
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paper_title: Indoor localization based on response rate of bluetooth inquiries

paper_content:

Location is considered as the most important and relevant context information. Bluetooth technology, being a common feature of commercial mobile devices, is a (or the) key technology that is pervasively available nowadays. There has been not much success in using Bluetooth technology for indoor localization, mainly due to the limitation of the technology. Using the Context Management Frame (CMF) infrastructure deployed in our office building, we have designed, implemented and evaluated a Bluetooth based indoor localization solution that determines the locations of stationary mobile users at a room level. The solution is based on the inquiry response rate of Bluetooth technology. This approach does not require establishing any connectivity between Bluetooth devices. Further, since the solution is infrastructure- and network-based, it does not require mobile devices to be upgraded in any way in order to be localized. The results of experiments show that our solution has 98% accuracy in rooms with full Bluetooth sensor coverage, when the target device being stationary for 3 minutes.
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paper_title: Archeoguide: system architecture of a mobile outdoor augmented reality system

paper_content:

We present the system architecture of a mobile outdoor augmented reality system for the Archeoguide project. We begin with a short introduction to the project. Then we present the hardware we chose for the mobile system and we describe the system architecture we designed for the software implementation. We conclude this paper with the first results obtained from experiments we made during our trials at ancient Olympia in Greece.
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paper_title: An accurate ultra wideband (UWB) ranging for precision asset location

paper_content:

This paper investigates a ranging method employing ultra wideband (UWB) pulses under the existence of the line of sight (LOS) path in a multipath environment. Our method is based on the estimation of time of arrival of the first multipath. It averages the received pulses over multiple time frames, performs a correlation operation on the averaged signal, and detects the peak of the correlated signal. Our method reduces the ranging accuracy over conventional methods, and its accuracy is close to the Cramer-Rao lower bound (CRLB) on even for a low SNR.
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paper_title: Indoor location sensing using geo-magnetism

paper_content:

We present an indoor positioning system that measures location using disturbances of the Earth's magnetic field caused by structural steel elements in a building. The presence of these large steel members warps the geomagnetic field in a way that is spatially varying but temporally stable. To localize, we measure the magnetic field using an array of e-compasses and compare the measurement with a previously obtained magnetic map. We demonstrate accuracy within 1 meter 88% of the time in experiments in two buildings and across multiple floors within the buildings. We discuss several constraint techniques that can maintain accuracy as the sample space increases.
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paper_title: The Cricket location-support system

paper_content:

This paper presents the design, implementation, and evaluation of Cricket , a location-support system for in-building, mobile, location-dependent applications. It allows applications running on mobile and static nodes to learn their physical location by using listeners that hear and analyze information from beacons spread throughout the building. Cricket is the result of several design goals, including user privacy, decentralized administration, network heterogeneity, and low cost. Rather than explicitly tracking user location, Cricket helps devices learn where they are and lets them decide whom to advertise this information to; it does not rely on any centralized management or control and there is no explicit coordination between beacons; it provides information to devices regardless of their type of network connectivity; and each Cricket device is made from off-the-shelf components and costs less than U.S. $10. We describe the randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques that improve accuracy. Our experience with Cricket shows that several location-dependent applications such as in-building active maps and device control can be developed with little effort or manual configuration.
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paper_title: Structured visual markers for indoor pathfinding

paper_content:

We present a mobile augmented reality (AR) system to guide a user through an unfamiliar building to a destination room. The system presents a world-registered wireframe model of the building labeled with directional information in a see-through heads-up display, and a three-dimensional world-in-miniature (WIM) map on a wrist-worn pad that also acts as an input device. Tracking is done using a combination of wall-mounted ARToolkit markers observed by a head-mounted camera, and an inertial tracker. To allow coverage of arbitrarily large areas with a limited set of markers, a structured marker re-use scheme based on graph coloring has been developed.
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paper_title: WearTrack: a self-referenced head and hand tracker for wearable computers and portable VR

paper_content:

This paper presents a new tracking technique which is essentially "sourceless" in that it can be used anywhere with no set-up, yet it enables a much wider range of virtual environment-style navigation and interaction techniques than does a simple head-orientation tracker. The new system is based on the very simple idea of combining a sourceless head orientation tracker with a head-worn tracking device that tracks a hand-mounted 3D beacon relative to the head. Because the seen graphical representation of the pointer accurately matches the felt hand position despite any errors in the orientation tracker, the system encourages use of intuitive interaction techniques which exploit proprioception. We describe a prototype of the tracking system, and discuss and demonstrate its application in a portable VR system and in a wearable computer user interface.
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paper_title: Virtual Vouchers: Prototyping a Mobile Augmented Reality User Interface for Botanical Species Identification

paper_content:

the tools that botanists require for field-work must evolve and take on new forms. Of particular importance is the ability to identify existing and new species in the field. Mobile augmented reality systems can make it possible to access, view, and inspect a large database of virtual species examples side-by-side with physical specimens. In this paper, we present prototypes of a mobile augmented reality electronic field guide and techniques for displaying and inspecting computer vision-based visual search results in the form of virtual vouchers. Our work addresses head-movement controlled augmented reality for hands-free interaction and tangible augmented reality. We describe results from our design and investigation process and discuss observations and feedback from lab trials by botanists.
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paper_title: Energy-efficient rate-adaptive GPS-based positioning for smartphones

paper_content:

Many emerging smartphone applications require position information to provide location-based or context-aware services. In these applications, GPS is often preferred over its alternatives such as GSM/WiFi based positioning systems because it is known to be more accurate. However, GPS is extremely power hungry. Hence a common approach is to periodically duty-cycle GPS. However, GPS duty-cycling trades-off positioning accuracy for lower energy. A key requirement for such applications, then, is a positioning system that provides accurate position information while spending minimal energy. In this paper, we present RAPS, rate-adaptive positioning system for smartphone applications. It is based on the observation that GPS is generally less accurate in urban areas, so it suffices to turn on GPS only as often as necessary to achieve this accuracy. RAPS uses a collection of techniques to cleverly determine when to turn on GPS. It uses the location-time history of the user to estimate user velocity and adaptively turn on GPS only if the estimated uncertainty in position exceeds the accuracy threshold. It also efficiently estimates user movement using a duty-cycled accelerometer, and utilizes Bluetooth communication to reduce position uncertainty among neighboring devices. Finally, it employs celltower-RSS blacklisting to detect GPS unavailability (e.g., indoors) and avoid turning on GPS in these cases. We evaluate RAPS through real-world experiments using a prototype implementation on a modern smartphone and show that it can increase phone lifetimes by more than a factor of 3.8 over an approach where GPS is always on.
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paper_title: User Interface Management Techniques for Collaborative Mobile Augmented Reality

paper_content:

Mobile Augmented Reality Systems (MARS) have the potential to revolutionize the way in which information is provided to users. Virtual information can be directly integrated with the real world surrounding the mobile user, who can interact with it to display related information, to pose and resolve queries, and to collaborate with other users. However, we believe that the benefits of MARS will only be achieved if the user interface (UI) is actively managed so as to maximize the relevance and minimize the confusion of the virtual material relative to the real world. This article addresses some of the steps involved in this process, focusing on the design and layout of the mobile user’s overlaid virtual environment. The augmented view of the user’s surroundings presents an interface to context-dependent operations, many of which are related to the objects in view—the augmented world is the user interface. We present three user interface design techniques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view management. Information filtering helps select the most relevant information to present to the user. UI component designdetermines the format in which this information should be conveyed, based on the available display resources and tracking accuracy. For example, the absence of high accuracy position tracking would favor body- or screenstabilized components over world-stabilized ones that would need to be exactly registered with the physical objects to which they refer. View management attempts to ensure that the virtual objects that are displayed visually are arranged appropriately with regard to their projections on the view plane. For example, the relationships among objects should be as unambiguous as possible, and physical or virtual objects should not obstruct the user’s view of more important physical or virtual objects in the scene. We illustrate these interface design techniques using our prototype collaborative, cross-site MARS environment, which is composed of mobile and non-mobile augmented reality and virtual reality systems.
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paper_title: LANDMARC: indoor location sensing using active RFID

paper_content:

Growing convergence among mobile computing devices and embedded technology sparks the development and deployment of “context-aware” applications, where location is the most essential context. In this paper we present LANDMARC, a location sensing prototype system that uses Radio Frequency Identification (RFID) technology for locating objects inside buildings. The major advantage of LANDMARC is that it improves the overall accuracy of locating objects by utilizing the concept of reference tags. Based on experimental analysis, we demonstrate that active RFID is a viable and cost-effective candidate for indoor location sensing. Although RFID is not designed for indoor location sensing, we point out three major features that should be added to make RFID technologies competitive in this new and growing market.
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paper_title: Interactive dirt: increasing mobile work performance with a wearable projector-camera system

paper_content:

Mobile teamwork requires people to maintain good situational awareness (SA) about their real world environments. Current mobile devices are highly portable, but their user interfaces (UIs) require too deep of focus of attention to allow their users to use them and simultaneously maintain SA. As a result, some mobile practitioners have little or no access to useful computer-based interactive services. Inspired by existing projector-camera systems, this paper studies the feasibility of developing a wearable projector-camera system that enables users to access human-computer interaction (HCI) services without negatively affecting their SA. A functional prototype of the "Interactive Dirt" system was developed using inexpensive commercial off-the-shelf technologies. A field experiment was conducted as a formative evaluation to test the utility of the prototype under extreme mobile teamwork requirements for SA--military stability and support operations (SASO). Results show strong potential to increase performance of mobile teams.
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paper_title: Human pacman: A mobile entertainment system with ubiquitous computing and tangible interaction over a wide outdoor area

paper_content:

Human Pacman is an interactive role-playing game that envisions to bring the computer gaming experience to a new level of emotional and sensory gratification by setting the real world as a playground. This is a physical fantasy game integrated with human-social and mobile-gaming that emphasizes on collaboration and competition between players. By setting the game in a wide outdoor area, natural human-physical movements have become an integral part of the game. Pacmen and Ghosts are now human players in the real world experiencing mixed reality visualization from the wearable computers on them. Virtual cookies and actual physical objects are incorporated to provide novel experiences of seamless transitions between real and virtual worlds and tangible human computer interface respectively. We believe Human Pacman is pioneering a new form of gaming that anchors on physicality, mobility, social interaction, and ubiquitous computing.
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paper_title: Efficient Extraction of Robust Image Features on Mobile Devices

paper_content:

Recent convergence of imaging sensors and general purpose processors on mobile phones creates an opportunity for a new class of augmented reality applications. Robust image feature extraction is a crucial enabler of this type of systems. In this article, we discuss an efficient mobile phone implementation of a state-of-the-art algorithm for computing robust image features called SURF. We implement several improvements to the basic algorithm that significantly improve its performance and reduce its memory footprint making the use of this algorithm on the mobile phone practical. Our prototype implementation has been applied to several practical applications such as image search, object recognition and augmented reality applications.
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paper_title: ARToolKitPlus for Pose Tracking on Mobile Devices

paper_content:

In this paper we present ARToolKitPlus, a successor to the popular ARToolKit pose tracking library. ARToolKitPlus has been optimized and extended for the usage on mobile devices such as smartphones, PDAs and Ultra Mobile PCs (UMPCs). We explain the need and specific requirements of pose tracking on mobile devices and how we met those requirements. To prove the applicability we performed an extensive benchmark series on a broad range of off-the-shelf handhelds.
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paper_title: Quantized embeddings of scale-invariant image features for mobile augmented reality

paper_content:

Randomized embeddings of scale-invariant image features are proposed for retrieval of object-specific meta data in an augmented reality application. The method extracts scale invariant features from a query image, computes a small number of quantized random projections of these features, and sends them to a database server. The server performs a nearest neighbor search in the space of the random projections and returns meta-data corresponding to the query image. Prior work has shown that binary embeddings of image features enable efficient image retrieval. This paper generalizes the prior art by characterizing the tradeoff between the number of random projections and the number of bits used to represent each projection. The theoretical results suggest a bit allocation scheme under a total bit rate constraint: It is often advisable to spend bits on a small number of finely quantized random measurements rather than on a large number of coarsely quantized random measurements. This theoretical result is corroborated via experimental study of the above tradeoff using the ZuBuD database. The proposed scheme achieves a retrieval accuracy up to 94% while requiring the mobile device to transmit only 2.5 kB to the database server, a significant improvement over 1-bit quantization schemes reported in prior art.
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paper_title: Outdoors augmented reality on mobile phone using loxel-based visual feature organization

paper_content:

We have built an outdoors augmented reality system for mobile phones that matches camera-phone images against a large database of location-tagged images using a robust image retrieval algorithm. We avoid network latency by implementing the algorithm on the phone and deliver excellent performance by adapting a state-of-the-art image retrieval algorithm based on robust local descriptors. Matching is performed against a database of highly relevant features, which is continuously updated to reflect changes in the environment. We achieve fast updates and scalability by pruning of irrelevant features based on proximity to the user. By compressing and incrementally updating the features stored on the phone we make the system amenable to low-bandwidth wireless connections. We demonstrate system robustness on a dataset of location-tagged images and show a smart-phone implementation that achieves a high image matching rate while operating in near real-time.
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paper_title: Mobile collaborative augmented reality

paper_content:

The combination of mobile computing and collaborative augmented reality into a single system makes the power of computer enhanced interaction and communication in the real world accessible anytime and everywhere. The paper describes our work to build a mobile collaborative augmented reality system that supports true stereoscopic 3D graphics, a pen and pad interface and direct interaction with virtual objects. The system is assembled from off-the-shelf hardware components and serves as a basic test bed for user interface experiments related to computer supported collaborative work in augmented reality. A mobile platform implementing the described features and collaboration between mobile and stationary users are demonstrated.
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paper_title: Distinctive Image Features from Scale-Invariant Keypoints

paper_content:

The Scale-Invariant Feature Transform (or SIFT) algorithm is a highly robust method to extract and consequently match distinctive invariant features from images. These features can then be used to reliably match objects in diering images. The algorithm was rst proposed by Lowe [12] and further developed to increase performance resulting in the classic paper [13] that served as foundation for SIFT which has played an important role in robotic and machine vision in the past decade.
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paper_title: Surf: Speeded up robust features

paper_content:

In this paper, we present a novel scale- and rotation-invariant interest point detector and descriptor, coined SURF (Speeded Up Robust Features). It approximates or even outperforms previously proposed schemes with respect to repeatability, distinctiveness, and robustness, yet can be computed and compared much faster. ::: ::: This is achieved by relying on integral images for image convolutions; by building on the strengths of the leading existing detectors and descriptors (in casu, using a Hessian matrix-based measure for the detector, and a distribution-based descriptor); and by simplifying these methods to the essential. This leads to a combination of novel detection, description, and matching steps. The paper presents experimental results on a standard evaluation set, as well as on imagery obtained in the context of a real-life object recognition application. Both show SURF's strong performance.
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paper_title: Natural Feature Tracking for Augmented Reality

paper_content:

Natural scene features stabilize and extend the tracking range of augmented reality (AR) pose-tracking systems. We develop robust computer vision methods to detect and track natural features in video images. Point and region features are automatically and adaptively selected for properties that lead to robust tracking. A multistage tracking algorithm produces accurate motion estimates, and the entire system operates in a closed-loop that stabilizes its performance and accuracy. We present demonstrations of the benefits of using tracked natural features for AR applications that illustrate direct scene annotation, pose stabilization, and extendible tracking range. Our system represents a step toward integrating vision with graphics to produce robust wide-area augmented realities.
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paper_title: Marker tracking and HMD calibration for a video-based augmented reality conferencing system

paper_content:

We describe an augmented reality conferencing system which uses the overlay of virtual images on the real world. Remote collaborators are represented on virtual monitors which can be freely positioned about a user in space. Users can collaboratively view and interact with virtual objects using a shared virtual whiteboard. This is possible through precise virtual image registration using fast and accurate computer vision techniques and head mounted display (HMD) calibration. We propose a method for tracking fiducial markers and a calibration method for optical see-through HMD based on the marker tracking.
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paper_title: Mobile augmented reality in the data center

paper_content:

Recent advances in compute power, graphics power, and cameras in mobile computing devices have facilitated the development of new augmented reality applications in the mobile device space. Mobile augmented reality provides a straightforward and natural way for users to understand complex data by overlaying visualization on top of a live video feed on their mobile device. In our data center mobile augmented reality project, the user points a mobile device camera at a rack of data center assets, and additional content about these assets is visually overlaid on top of each asset in the video stream from the mobile device camera. This correspondence between digital content and physical things or locations makes mobile augmented reality an intuitive user interface for interacting with the world around us. This paper describes augmented reality techniques for mobile devices and the motivations around using a multimarker computer vision-based technique for visualizing asset data in the data center. Our mobile augmented reality project enables system administrators to easily interact with hardware assets while they are in the data center, providing them with an additional tool to use in managing the data center.
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paper_title: SURFTrac: Efficient tracking and continuous object recognition using local feature descriptors

paper_content:

We present an efficient algorithm for continuous image recognition and feature descriptor tracking in video which operates by reducing the search space of possible interest points inside of the scale space image pyramid. Instead of performing tracking in 2D images, we search and match candidate features in local neighborhoods inside the 3D image pyramid without computing their feature descriptors. The candidates are further validated by fitting to a motion model. The resulting tracked interest points are more repeatable and resilient to noise, and descriptor computation becomes much more efficient because only those areas of the image pyramid that contain features are searched. We demonstrate our method on real-time object recognition and label augmentation running on a mobile device.
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paper_title: UMAR: Ubiquitous Mobile Augmented Reality

paper_content:

In this paper we discuss the prospects of using marker based Augmented Reality for context aware applications on mobile phones. We also present the UMAR, a conceptual framework for developing Ubiquitous Mobile Augmented Reality applications which consists of research areas identified as relevant for successfully bridging the physical world and the digital domain using Mobile Augmented Reality. A step towards this we have successfully ported the ARToolkit to consumer mobile phones running on the Symbian platform and present results around this. We also present three sample applications based on UMAR and future case study work planned.
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paper_title: Feature Tracking for Mobile Augmented Reality Using Video Coder Motion Vectors

paper_content:

We propose a novel, low-complexity, tracking scheme that uses motion vectors directly from a video coder. We compare our tracking algorithm against ground truth data, and show that we can achieve a high level of accuracy, even though the motion vectors are rate-distortion optimized and do not represent true motion. We develop a framework for tracking in video sequences with various GOP structures. Such a scheme would find applications in the context of Mobile Augmented Reality. The proposed feature tracking algorithm can significantly reduce the required rate of feature extraction and matching.
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paper_title: Scene modelling, recognition and tracking with invariant image features

paper_content:

We present a complete system architecture for fully automated markerless augmented reality (AR). The system constructs a sparse metric model of the real-world environment, provides interactive means for specifying the pose of a virtual object, and performs model-based camera tracking with visually pleasing augmentation results. Our approach does not require camera pre-calibration, prior knowledge of scene geometry, manual initialization of the tracker or placement of special markers. Robust tracking in the presence of occlusions and scene changes is achieved by using highly distinctive natural features to establish image correspondences.
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paper_title: A Mobile Vision System for Urban Detection with Informative Local Descriptors

paper_content:

We present a computer vision system for the detection and identification of urban objects from mobile phone imagery, e.g., for the application of tourist information services. Recognition is based on MAP decision making over weak object hypotheses from local descriptor responses in the mobile imagery. We present an improvement over the standard SIFT key detector [7] by selecting only informative (i-SIFT) keys for descriptor matching. Selection is applied first to reduce the complexity of the object model and second to accelerate detection by selective filtering. We present results on the MPG-20 mobile phone imagery with severe illumination, scale and viewpoint changes in the images, performing with ≈ 98% accuracy in identification, efficient (100%) background rejection, efficient (0%) false alarm rate, and reliable quality of service under extreme illumination conditions, significantly improving standard SIFT based recognition in every sense, providing - important for mobile vision - runtimes which are ≈ 8 (≈24) times faster for the MPG-20 (ZuBuD) database.
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paper_title: Video see-through AR on consumer cell-phones

paper_content:

We present a first running video see-through augmented reality system on a consumer cell-phone. It supports the detection and differentiation of different markers, and correct integration of rendered 3D graphics into the live video stream via a weak perspective projection camera model and an OpenGL rendering pipeline.
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paper_title: ARTag, a fiducial marker system using digital techniques

paper_content:

Fiducial marker systems consist of patterns that are mounted in the environment and automatically detected in digital camera images using an accompanying detection algorithm. They are useful for augmented reality (AR), robot navigation, and general applications where the relative pose between a camera and object is required. Important parameters for such marker systems is their false detection rate (false positive rate), their inter-marker confusion rate, minimal detection size (in pixels) and immunity to lighting variation. ARTag is a marker system that uses digital coding theory to get a very low false positive and inter-marker confusion rate with a small required marker size, employing an edge linking method to give robust lighting variation immunity. ARTag markers are bi-tonal planar patterns containing a unique ID number encoded with robust digital techniques of checksums and forward error correction (FEC). This proposed new system, ARTag has very low and numerically quantifiable error rates, does not require a grey scale threshold as does other marker systems, and can encode up to 2002 different unique ID's with no need to store patterns. Experimental results are shown validating this system.
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paper_title: OpenTracker-an open software architecture for reconfigurable tracking based on XML

paper_content:

This paper describes OpenTracker, an open software architecture that provides a generic solution to the different tasks involved in tracking input devices and processing tracking data for virtual environments. It combines a highly modular design with a configuration syntax based on XML, thus taking full advantage of this new technology. OpenTracker is a first attempt towards a "write once, track anywhere" approach to virtual reality application development.
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paper_title: InfoSPOT: A mobile Augmented Reality method for accessing building information through a situation awareness approach

paper_content:

article i nfo Article history: Accepted 9 September 2012 Available online 6 October 2012 The Architecture, Engineering, Construction, and Owner/Operator (AECO) industry is constantly searching for new methods for increasing efficiency and productivity. Facility Managers (FMs), as a part of the owner/ operator role, work in complex and dynamic environments where critical decisions are constantly made. This decision-making process and its consequent performance can be improved by enhancing Situation Awareness (SA) of the FMs through new digital technologies. In this paper, InfoSPOT (Information Surveyed Point for Observation and Tracking), is recommended to FMs as a mobile Augmented Reality (AR) tool for accessing information about the facilities they maintain. AR has been considered as a viable option to reduce inefficiencies of data overload by providing FMs with a SA-based tool for visualizing their "real-world" envi- ronment with added interactive data. A prototype of the AR application was developed and a user participa- tion experiment and analysis conducted to evaluate the features of InfoSPOT. This innovative application of AR has the potential to improve construction practices, and in this case, facility management. Published by Elsevier B.V.
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paper_title: Model-based visual tracking for outdoor augmented reality applications

paper_content:

Outdoor augmented reality (AR) applications rely on hybrid tracking (GPS, digital compass, visual) for registration. RSC has developed a real-time visual tracking system that uses visual cues of buildings in an urban environment for correcting the results of a conventional tracking system. This approach relies on knowledge of a CAD model of the building. It not only provides motion estimation, but also absolute orientation/position. It is based on the "visual servoing" approach, originally developed for robotics tasks. We have demonstrated this approach in real-time at a building on the NRL campus This poster shows the approach and results. The concept can be generalized to any scenario where a CAD model is available. This system is being prepared for integration into the NRL system BARS (Battlefield Augmented Reality System).
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paper_title: Sketching up the world: in situ authoring for mobile Augmented Reality

paper_content:

We present a novel system allowing in situ content creation for mobile Augmented Reality in unprepared environments. This system targets smartphones and therefore allows a spontaneous authoring while in place. We describe two different scenarios, which are depending on the size of the working environment and consequently use different tracking techniques. A natural feature-based approach for planar targets is used for small working spaces whereas for larger working environments, such as in outdoor scenarios, a panoramic-based orientation tracking is deployed. Both are integrated into one system allowing the user to use the same interaction for creating the content applying a set of simple, yet powerful modeling functions for content creation. The resulting content for Augmented Reality can be shared with other users using a dedicated content server or kept in a private inventory for later use.
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paper_title: Going out: robust model-based tracking for outdoor augmented reality

paper_content:

This paper presents a model-based hybrid tracking system for outdoor augmented reality in urban environments enabling accurate, realtime overlays for a handheld device. The system combines several well-known approaches to provide a robust experience that surpasses each of the individual components alone: an edge-based tracker for accurate localisation, gyroscope measurements to deal with fast motions, measurements of gravity and magnetic field to avoid drift, and a back store of reference frames with online frame selection to re-initialize automatically after dynamic occlusions or failures. A novel edge-based tracker dispenses with the conventional edge model, and uses instead a coarse, but textured, 3D model. This yields several advantages: scale-based detail culling is automatic, appearance-based edge signatures can be used to improve matching and the models needed are more commonly available. The accuracy and robustness of the resulting system is demonstrated with comparisons to map-based ground truth data.
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paper_title: Location-based augmented reality on mobile phones

paper_content:

The computational capability of mobile phones has been rapidly increasing, to the point where augmented reality has become feasible on cell phones. We present an approach to indoor localization and pose estimation in order to support augmented reality applications on a mobile phone platform. Using the embedded camera, the application localizes the device in a familiar environment and determines its orientation. Once the 6 DOF pose is determined, 3D virtual objects from a database can be projected into the image and displayed for the mobile user. Off-line data acquisition consists of acquiring images at different locations in the environment. The online pose estimation is done by a feature-based matching between the cell phone image and an image selected from the precomputed database using the phone's sensors (accelerometer and magnetometer). The application enables the user both to visualize virtual objects in the camera image and to localize the user in a familiar environment. We describe in detail the process of building the database and the pose estimation algorithm used on the mobile phone. We evaluate the algorithm performance as well as its accuracy in terms of reprojection distance of the 3D virtual objects in the cell phone image.
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paper_title: Fusion of vision, GPS and 3D gyro data in solving camera registration problem for direct visual navigation

paper_content:

This paper presents a precise and robust camera registration solution for the novel vision-based road navigation system - VICNAS, which superimposes virtual 3D navigation indicators and traffic signs upon the real road view in an Augmented Reality (AR) space. Traditional vision based or inertial sensor based solutions of registration problem are mostly designed for well-structured environment, which is however unavailable in a wide-open uncontrolled road environment for navigation purposes. This paper proposed a hybrid system that combines computer vision, GPS and 3D inertial gyroscope technologies to provide precise and robust camera pose estimation. The fusion approach is based on our PMM (parameterized model matching) algorithm, in which the road shape model is derived from the digital map data, and matched with road features extracted from real images. Inertial data estimates the initial possible motion, and also serves as relative tolerance to stable the pose output. The algorithms proposed in this paper are validated with the experimental results of real road tests under different road conditions.
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paper_title: Augmenting 3D urban environment using mobile devices

paper_content:

We describe an augmented reality prototype for exploring a 3D urban environment on mobile devices. Our system utilizes the location and orientation sensors on the mobile platform as well as computer vision techniques to register the live view of the device with the 3D urban data. In particular, the system recognizes the buildings in the live video, tracks the camera pose, and augments the video with relevant information about the buildings in the correct perspective. The 3D urban data consist of 3D point clouds and corresponding geo-tagged RGB images of the urban environment. We also discuss the processing steps to make such 3D data scalable and usable by our system.
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paper_title: Outdoors augmented reality on mobile phone using loxel-based visual feature organization

paper_content:

We have built an outdoors augmented reality system for mobile phones that matches camera-phone images against a large database of location-tagged images using a robust image retrieval algorithm. We avoid network latency by implementing the algorithm on the phone and deliver excellent performance by adapting a state-of-the-art image retrieval algorithm based on robust local descriptors. Matching is performed against a database of highly relevant features, which is continuously updated to reflect changes in the environment. We achieve fast updates and scalability by pruning of irrelevant features based on proximity to the user. By compressing and incrementally updating the features stored on the phone we make the system amenable to low-bandwidth wireless connections. We demonstrate system robustness on a dataset of location-tagged images and show a smart-phone implementation that achieves a high image matching rate while operating in near real-time.
---
paper_title: UMAR: Ubiquitous Mobile Augmented Reality

paper_content:

In this paper we discuss the prospects of using marker based Augmented Reality for context aware applications on mobile phones. We also present the UMAR, a conceptual framework for developing Ubiquitous Mobile Augmented Reality applications which consists of research areas identified as relevant for successfully bridging the physical world and the digital domain using Mobile Augmented Reality. A step towards this we have successfully ported the ARToolkit to consumer mobile phones running on the Symbian platform and present results around this. We also present three sample applications based on UMAR and future case study work planned.
---
paper_title: Data Management Strategies for Mobile Augmented Reality

paper_content:

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.
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paper_title: Towards Massively Multi-user Augmented Reality on Handheld Devices

paper_content:

Augmented Reality (AR) can naturally complement mobile computing on wearable devices by providing an intuitive interface to a three-dimensional information space embedded within physical reality. Unfortunately, current wearable AR systems are relatively complex, expensive, fragile and heavy, rendering them unfit for large-scale deployment involving untrained users outside constrained laboratory environments. Consequently, the scale of collaborative multi-user experiments have not yet exceeded a handful of participants. In this paper, we present a system architecture for interactive, infrastructure-independent multi-user AR applications running on off-the-shelf handheld devices. We implemented a four-user interactive game installation as an evaluation setup to encourage playful engagement of participants in a cooperative task. Over the course of five weeks, more than five thousand visitors from a wide range of professional and socio-demographic backgrounds interacted with our system at four different locations.
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paper_title: The need for real time consistency management in P2P mobile gaming environments

paper_content:

The introduction of more powerful, feature rich, portable handsets is enabling more engaging mobile multimedia entertainment. Improvements in wireless technology infrastructure are enabling access to ubiquitous, always-on data networks. We believe that based on the popularity of multiplayer games over IP networks, there will be significant demand for mobile multiplayer games. Based upon our early trials, we also believe that the current trend for using centralised client/server models will not offer the most suitable architecture to enable them. To support our research we have built a novel augmented reality real time game as a requirements gatherer for gaming in a wireless environment. In this paper we indicate why a centralised approach will not be suitable for real-time interactions. As an alternative we propose a decentralised approach which includes support for consistency and interest management over heterogeneous networked wireless environments.
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paper_title: Map torchlight: a mobile augmented reality camera projector unit

paper_content:

The advantages of paper-based maps have been utilized in the field of mobile Augmented Reality (AR) in the last few years. Traditional paper-based maps provide high-resolution, large-scale information with zero power consumption. There are numerous implementations of magic lens interfaces that combine high-resolution paper maps with dynamic handheld displays. From an HCI perspective, the main challenge of magic lens interfaces is that users have to switch their attention between the magic lens and the information in the background. In this paper, we attempt to overcome this problem by using a lightweight mobile camera projector unit to augment the paper map directly with additional information. The "Map Torchlight" is tracked over a paper map and can precisely highlight points of interest, streets, and areas to give directions or other guidance for interacting with the map.
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paper_title: Collecting big datasets of human activity one checkin at a time

paper_content:

A variety of cutting edge applications for mobile phones exploit the availability of phone sensors to accurately infer the user activity and location to offer more effective services. To validate and evaluate these new applications, appropriate and extensive datasets are needed: in particular, large sets of traces of sensor data (accelerometer, GPS, micro- phone, etc.), labelled with corresponding user activities. So far, such traces have only been collected in short-lived, small-scale setups. The primary reason for this is the difficulty in establishing accurate ground truth information outside the laboratory. Here, we present our vision of a system for large-scale sensor data capturing, leveraging all sensors of todays smart phones, with the aim of generating a large dataset that is augmented with appropriate ground-truth information. The primary challenges that we address consider the energy cost on the mobile device and the incentives for users to keep running the system on their device for longer. We argue for leveraging the concept of the checkin - as successfully introduced in online social networks (e.g. Foursquare) - for collecting activity and context related datasets. With a checkin, a user deliberately provides a small piece of data about their behaviour while enabling the system to adjust sensing and data collection around important activities. In this work we present up2, a mobile app letting users check in to their current activity (e.g., "waiting for the bus", "riding a bicycle", "having dinner"). After a checkin, we use the phone's sensors (GPS, accelerometer, microphone, etc.) to gather data about the user's activity and surrounding. This makes up2 a valuable tool for research in sensor based activity detection.
---
paper_title: Data Management Strategies for Mobile Augmented Reality

paper_content:

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.
---
paper_title: APRIL: a high-level framework for creating augmented reality presentations

paper_content:

While augmented reality (AR) technology is steadily maturing, application development is still lacking advanced authoring tools - even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for the structuring of AR content. In this paper we present APRIL, the Augmented Presentation and Interaction Language, an authoring platform for AR presentations which provides concepts and techniques that are independent of specific applications or target hardware platforms, and should be suitable to raise the level of abstraction on which AR content creators can operate.
---
paper_title: Data Management Strategies for Mobile Augmented Reality

paper_content:

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.
---
paper_title: User Interface Management Techniques for Collaborative Mobile Augmented Reality

paper_content:

Mobile Augmented Reality Systems (MARS) have the potential to revolutionize the way in which information is provided to users. Virtual information can be directly integrated with the real world surrounding the mobile user, who can interact with it to display related information, to pose and resolve queries, and to collaborate with other users. However, we believe that the benefits of MARS will only be achieved if the user interface (UI) is actively managed so as to maximize the relevance and minimize the confusion of the virtual material relative to the real world. This article addresses some of the steps involved in this process, focusing on the design and layout of the mobile user’s overlaid virtual environment. The augmented view of the user’s surroundings presents an interface to context-dependent operations, many of which are related to the objects in view—the augmented world is the user interface. We present three user interface design techniques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view management. Information filtering helps select the most relevant information to present to the user. UI component designdetermines the format in which this information should be conveyed, based on the available display resources and tracking accuracy. For example, the absence of high accuracy position tracking would favor body- or screenstabilized components over world-stabilized ones that would need to be exactly registered with the physical objects to which they refer. View management attempts to ensure that the virtual objects that are displayed visually are arranged appropriately with regard to their projections on the view plane. For example, the relationships among objects should be as unambiguous as possible, and physical or virtual objects should not obstruct the user’s view of more important physical or virtual objects in the scene. We illustrate these interface design techniques using our prototype collaborative, cross-site MARS environment, which is composed of mobile and non-mobile augmented reality and virtual reality systems.
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paper_title: Location based Applications for Mobile Augmented Reality

paper_content:

In this work we investigate building indoor location based applications for a mobile augmented reality system. We believe that augmented reality is a natural interface to visualize spacial information such as position or direction of locations and objects for location based applications that process and present information based on the user's position in the real world. To enable such applications we construct an indoor tracking system that covers a substantial part of a building. It is based on visual tracking of fiducial markers enhanced with an inertial sensor for fast rotational updates. To scale such a system to a whole building we introduce a space partitioning scheme to reuse fiducial markers throughout the environment. Finally we demonstrate two location based applications built upon this facility, an indoor navigation aid and a library search application.
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paper_title: Muddleware for Prototyping Mixed Reality Multiuser Games

paper_content:

We present Muddleware, a communication platform designed for mixed reality multi-user games for mobile, lightweight clients. An approach inspired by Tuplespaces, which provides decoupling of sender and receiver is used to address the requirements of a potentially large number of mobile clients. A hierarchical database built on XML technology allows convenient prototyping and simple, yet powerful queries. Server side-extensions address persistence and autonomous behaviors through hierarchical state machines. The architecture has been tested with a number of multi-user games and is also used for non-entertainment applications
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paper_title: Sensor fusion and occlusion refinement for tablet-based AR

paper_content:

This paper presents a set of technologies which enable robust, accurate, high resolution augmentation of live video, delivered via a tablet PC to which a video camera has been attached. By combining several technologies, this is achieved without the use of contrived markers in the environment: An outside-in tracker observes the tablet to generate robust, low-accuracy pose estimates. An inside-out tracker running on the tablet observes the video feed from the tablet-mounted camera and provides high-accuracy pose estimates by tracking natural features in the environment. Information from both of these trackers is combined in an extended Kalman filter. Finally, to maximise the quality of the augmented imagery, boundaries where the real world occludes the virtual imagery are identified and another tracker is used to refine the boundaries between real and virtual imagery so that their synthesis is as convincing as possible.
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paper_title: Design and optimization of image processing algorithms on mobile GPU

paper_content:

The advent of GPUs with programmable shaders on mobile phones has motivated developers to utilize GPU to offload computationally intensive tasks and relive the burden of embedded CPU. In this paper, we present a set of metrics to measure characteristics of a mobile phone GPU with the focus on image processing algorithms. These measures assist users in design and implementation stage and in classifying bottlenecks. We propose techniques to achieve increased performance with optimized shader design. To show the effectiveness of the proposed techniques, we employ cartoon-style non-photorealistic rendering (NPR), belief propagation (BP) stereo matching [Yang et al. 2006], and speeded up robust features (SURF) detection [Bay et al. 2008] as our example algorithms.
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paper_title: OpenCL embedded profile prototype in mobile device

paper_content:

Programmable Graphics Processing Unit (GPU) has over the years become an integral part of today's computing systems. The GPU use-cases have gradually been extended from graphics towards a wide range of applications. Since the programmable GPU is now making its way to mobile devices, it is interesting to study these new use-cases also there. To test this, we created a programming environment based on the embedded profile of the fresh Khronos OpenCL standard and ran it against an image processing workload in a mobile device with CPU and GPU back-ends. The early results on performance and energy consumption with CPU+GPU configuration were promising but also suggest there is room for optimization.
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paper_title: Sensor fusion and occlusion refinement for tablet-based AR

paper_content:

This paper presents a set of technologies which enable robust, accurate, high resolution augmentation of live video, delivered via a tablet PC to which a video camera has been attached. By combining several technologies, this is achieved without the use of contrived markers in the environment: An outside-in tracker observes the tablet to generate robust, low-accuracy pose estimates. An inside-out tracker running on the tablet observes the video feed from the tablet-mounted camera and provides high-accuracy pose estimates by tracking natural features in the environment. Information from both of these trackers is combined in an extended Kalman filter. Finally, to maximise the quality of the augmented imagery, boundaries where the real world occludes the virtual imagery are identified and another tracker is used to refine the boundaries between real and virtual imagery so that their synthesis is as convincing as possible.
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paper_title: Implementation and optimization of image processing algorithms on handheld GPU

paper_content:

The advent of GPUs with programmable shaders on handheld devices has motivated embedded application developers to utilize GPU to offload computationally intensive tasks and relieve the burden from embedded CPU. In this work, we propose an image processing toolkit on handheld GPU with programmable shaders using OpenGL ES 2.0 API. By using the image processing toolkit, we show that a range of image processing algorithms map readily to handheld GPU. We employ real-time video scaling, cartoon-style non-photorealistic rendering, and Harris corner detector as our example applications. In addition, we propose techniques to achieve increased performance with optimized shader design and efficient sharing of GPU workload between vertex and fragment shaders. Performance is evaluated in terms of frames per second at varying video stream resolution.
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paper_title: Augmented assembly using a mobile phone

paper_content:

We present a mobile phone based augmented reality (AR) assembly system that enable users to view complex models on their mobile phones. It is based on a client-server architecture, where complex model information is located on a PC, and a mobile phone with the camera is used as a thin client access device to this information. With this system users are able to see an AR view that provides step by step guidance for a real world assembly task. We also present results from a pilot user study evaluating the system, showing that people felt the interface was intuitive and very helpful in supporting the assembly task.
---
paper_title: Video see-through AR on consumer cell-phones

paper_content:

We present a first running video see-through augmented reality system on a consumer cell-phone. It supports the detection and differentiation of different markers, and correct integration of rendered 3D graphics into the live video stream via a weak perspective projection camera model and an OpenGL rendering pipeline.
---
paper_title: Extraction of Natural Feature Descriptors on Mobile GPUs

paper_content:

In this thesis the feasibility of a GPGPU (general-purpose computing on graphics processing units) approach to natural feature description on mobile phone GPUs is assessed. To this end, the SURF descriptor [4] has been implemented with OpenGL ES 2.0/GLSL ES 1.0 and evaluated across different mobile devices. The implementation is multiple times faster than a comparable CPU variant on the same device. The results proof the feasibility of modern mobile graphics accelerators for GPGPU tasks especially for the detection phase in natural feature tracking used in augmented reality applications. Extensive analysis and benchmarking of this approach in comparison to state of the art methods have been undertaken. Insights into the modifications necessary to adapt and modify the SURF algorithm to the limitations of a mobile GPU are presented. Further, an outlook for a GPGPU-based tracking pipeline on a mobile device is provided.
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paper_title: Using mobile GPU for general-purpose computing – a case study of face recognition on smartphones

paper_content:

As GPU becomes an integrated component in handheld devices like smartphones, we have been investigating the opportunities and limitations of utilizing the ultra-low-power GPU in a mobile platform as a general-purpose accelerator, similar to its role in desktop and server platforms. The special focus of our investigation has been on mobile GPU's role for energy-optimized real-time applications running on battery-powered handheld devices. In this work, we use face recognition as an application driver for our study. Our implementations on a smartphone reveals that, utilizing the mobile GPU as a co-processor can achieve significant speedup in performance as well as substantial reduction in total energy consumption, in comparison with a mobile-CPU-only implementation on the same platform.
---
paper_title: Extraction of Natural Feature Descriptors on Mobile GPUs

paper_content:

In this thesis the feasibility of a GPGPU (general-purpose computing on graphics processing units) approach to natural feature description on mobile phone GPUs is assessed. To this end, the SURF descriptor [4] has been implemented with OpenGL ES 2.0/GLSL ES 1.0 and evaluated across different mobile devices. The implementation is multiple times faster than a comparable CPU variant on the same device. The results proof the feasibility of modern mobile graphics accelerators for GPGPU tasks especially for the detection phase in natural feature tracking used in augmented reality applications. Extensive analysis and benchmarking of this approach in comparison to state of the art methods have been undertaken. Insights into the modifications necessary to adapt and modify the SURF algorithm to the limitations of a mobile GPU are presented. Further, an outlook for a GPGPU-based tracking pipeline on a mobile device is provided.
---
paper_title: ARToolKitPlus for Pose Tracking on Mobile Devices

paper_content:

In this paper we present ARToolKitPlus, a successor to the popular ARToolKit pose tracking library. ARToolKitPlus has been optimized and extended for the usage on mobile devices such as smartphones, PDAs and Ultra Mobile PCs (UMPCs). We explain the need and specific requirements of pose tracking on mobile devices and how we met those requirements. To prove the applicability we performed an extensive benchmark series on a broad range of off-the-shelf handhelds.
---
paper_title: Design and optimization of image processing algorithms on mobile GPU

paper_content:

The advent of GPUs with programmable shaders on mobile phones has motivated developers to utilize GPU to offload computationally intensive tasks and relive the burden of embedded CPU. In this paper, we present a set of metrics to measure characteristics of a mobile phone GPU with the focus on image processing algorithms. These measures assist users in design and implementation stage and in classifying bottlenecks. We propose techniques to achieve increased performance with optimized shader design. To show the effectiveness of the proposed techniques, we employ cartoon-style non-photorealistic rendering (NPR), belief propagation (BP) stereo matching [Yang et al. 2006], and speeded up robust features (SURF) detection [Bay et al. 2008] as our example algorithms.
---
paper_title: iPACKMAN: high-quality, low-complexity texture compression for mobile phones

paper_content:

We present a novel texture compression scheme, called iPACKMAN, targeted for hardware implementation. In terms of image quality, it outperforms the previous de facto standard texture compression algorithms in the majority of all cases that we have tested. Our new algorithm is an extension of the PACKMAN texture compression system, and while it is a bit more complex than PACKMAN, it is still very low in terms of hardware complexity.
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paper_title: Graphics Processing Units for Handhelds

paper_content:

During the past few years, mobile phones and other handheld devices have gone from only handling dull text-based menu systems to, on an increasing number of models, being able to render high-quality three-dimensional graphics at high frame rates. This paper is a survey of the special considerations that must be taken when designing graphics processing units (GPUs) on such devices. Starting off by introducing desktop GPUs as a reference, the paper discusses how mobile GPUs are designed, often with power consumption rather than performance as the primary goal. Lowering the bus traffic between the GPU and the memory is an efficient way of reducing power consumption, and therefore some high-level algorithms for bandwidth reduction are presented. In addition, an overview of the different APIs that are used in the handheld market to handle both two-dimensional and three-dimensional graphics is provided. Finally, we present our outlook for the future and discuss directions of future research on handheld GPUs.
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paper_title: Graphics for the masses: a hardware rasterization architecture for mobile phones

paper_content:

The mobile phone is one of the most widespread devices with rendering capabilities. Those capabilities have been very limited because the resources on such devices are extremely scarce; small amounts of memory, little bandwidth, little chip area dedicated for special purposes, and limited power consumption. The small display resolutions present a further challenge; the angle subtended by a pixel is relatively large, and therefore reasonably high quality rendering is needed to generate high fidelity images.To increase the mobile rendering capabilities, we propose a new hardware architecture for rasterizing textured triangles. Our architecture focuses on saving memory bandwidth, since an external memory access typically is one of the most energy-consuming operations, and because mobile phones need to use as little power as possible. Therefore, our system includes three new key innovations: I) an inexpensive multisampling scheme that gives relatively high quality at the same cost of previous inexpensive schemes, II) a texture minification system, including texture compression, which gives quality relatively close to trilinear mipmapping at the cost of 1.33 32-bit memory accesses on average, III) a scanline-based culling scheme that avoids a significant amount of z-buffer reads, and that only requires one context. Software simulations show that these three innovations together significantly reduce the memory bandwidth, and thus also the power consumption.
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paper_title: Pixel-planes 5: a heterogeneous multiprocessor graphics system using processor-enhanced memories

paper_content:

This paper introduces the architecture and initial algorithms for Pixel-Planes 5, a heterogeneous multi-computer designed both for high-speed polygon and sphere rendering (1M Phong-shaded triangles/second) and for supporting algorithm and application research in interactive 3D graphics. Techniques are described for volume rendering at multiple frames per second, font generation directly from conic spline descriptions, and rapid calculation of radiosity form-factors. The hardware consists of up to 32 math-oriented processors, up to 16 rendering units, and a conventional 1280 t 1024-pixel frame buffer, interconnected by a 5 gigabit ring network. Each rendering unit consists of a 128 t 128-pixel array of processors-with-memory with parallel quadratic expression evaluation for every pixel. Implemented on 1.6 micron CMOS chips designed to run at 40MHz, this array has 208 bits/pixel on-chip and is connected to a video RAM memory system that provides 4,096 bits of off-chip memory. Rendering units can be independently reasigned to any part of the screen or to non-screen-oriented computation. As of April 1989, both hardware and software are still under construction, with initial system operation scheduled for fall 1989.
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paper_title: Retargeting vector animation for small displays

paper_content:

We present a method that preserves the recognizability of key object interactions in a vector animation. The method allows an artist to author an animation once, and then output it to any display device. We specifically target mobile devices with small screen sizes. In order to adapt an animation, the author specifies an importance value for objects in the animation. The algorithm then identifies and categorizes the vector graphics objects that comprise the animation, leveraging the implicit relationship between extensible Markup Language (XML) and scalable vector graphics (SVG). Based on importance, the animation can then be automatically retargeted for any display using artistically motivated resizing and grouping algorithms that budget size and spatial detail for each object.
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paper_title: PCU: the programmable culling unit

paper_content:

Culling techniques have always been a central part of computer graphics, but graphics hardware still lack efficient and flexible support for culling. To improve the situation, we introduce the programmable culling unit, which is as flexible as the fragment program unit and capable of quickly culling entire blocks of fragments. Furthermore, it is very easy for the developer to use the PCU as culling programs can be automatically derived from fragment programs containing a discard instruction. Our PCU can be integrated into an existing fragment program unit with a modest hardware overhead of only about 10%. Using the PCU, we have observed shader speedups between 1.4 and 2.1 for relevant scenes.
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paper_title: Parametric analysis for adaptive computation offloading

paper_content:

Many programs can be invoked under different execution options, input parameters and data files. Such different execution contexts may lead to strikingly different execution instances. The optimal code generation may be sensitive to the execution instances. In this paper, we show how to use parametric program analysis to deal with this issue for the optimization problem of computation offloading.Computation offloading has been shown to be an effective way to improve performance and energy saving on mobile devices. Optimal program partitioning for computation offloading depends on the tradeoff between the computation workload and the communication cost. The computation workload and communication requirement may change with different execution instances. Optimal decisions on program partitioning must be made at run time when sufficient information about workload and communication requirement becomes available.Our cost analysis obtains program computation workload and communication cost expressed as functions of run-time parameters, and our parametric partitioning algorithm finds the optimal program partitioning corresponding to different ranges of run-time parameters. At run time, the transformed program self-schedules its tasks on either the mobile device or the server, based on the optimal program partitioning that corresponds to the current values of run-time parameters. Experimental results on an HP IPAQ handheld device show that different run-time parameters can lead to quite different program partitioning decisions.
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paper_title: A Streaming-Based Solution for Remote Visualization of 3D Graphics on Mobile Devices

paper_content:

Mobile devices such as personal digital assistants, tablet PCs, and cellular phones have greatly enhanced user capability to connect to remote resources. Although a large set of applications is now available bridging the gap between desktop and mobile devices, visualization of complex 3D models is still a task hard to accomplish without specialized hardware. This paper proposes a system where a cluster of PCs, equipped with accelerated graphics cards managed by the Chromium software, is able to handle remote visualization sessions based on MPEG video streaming involving complex 3D models. The proposed framework allows mobile devices such as smart phones, personal digital assistants (PDAs), and tablet PCs to visualize objects consisting of millions of textured polygons and voxels at a frame rate of 30 fps or more depending on hardware resources at the server side and on multimedia capabilities at the client side. The server is able to concurrently manage multiple clients computing a video stream for each one; resolution and quality of each stream is tailored according to screen resolution and bandwidth of the client. The paper investigates in depth issues related to latency time, bit rate and quality of the generated stream, screen resolutions, as well as frames per second displayed
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paper_title: Virtualized Screen: A Third Element for Cloud–Mobile Convergence

paper_content:

Mobile and cloud computing have emerged as the new computing platforms and are converging into a powerful cloud-mobile computing platform. This article envisions a virtualized screen as a new dimension in such a platform to further optimize the overall computing experience for users. In a virtualized screen, screen rendering is done in the cloud, and delivered as images to the client for interactive display. This enables thin-client mobile devices to enjoy many computationally intensive and graphically rich services. Technical challenges are discussed and addressed. Two novel cloud-mobile applications, Cloud Browser and Cloud Phone, are presented to demonstrate the advantages of such a virtualized screen.
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paper_title: Using bandwidth data to make computation offloading decisions

paper_content:

We present a framework for making computation offloading decisions in computational grid settings in which schedulers determine when to move parts of a computation to more capable resources to improve performance. Such schedulers must predict when an offloaded computation will outperform one that is local by forecasting the local cost (execution time for computing locally) and remote cost (execution time for computing remotely and transmission time for the input/output of the computation to/from the remote system). Typically, this decision amounts to predicting the bandwidth between the local and remote systems to estimate these costs. Our framework unifies such decision models by formulating the problem as a statistical decision problem that can either be treated "classically" or using a Bayesian approach. Using an implementation of this framework, we evaluate the efficacy of a number of different decision strategies (several of which have been employed by previous systems). Our results indicate that a Bayesian approach employing automatic change-point detection when estimating the prior distribution is the best-performing approach.
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paper_title: From Augmented Reality to Augmented Computing: A Look at Cloud-Mobile Convergence

paper_content:

There has been considerable number of virtual and augmented reality applications designed and developed for mobile devices. However the state-of-the-art systems are commonly confined by several limitations. In this position paper the concept ”Cloud-Mobile Convergence for Virtual Reality (CMCVR)” is presented. CMCVR envisions effective and user-friendly integration of the mobile device and cloud-based resources. Through the proposed framework, mobile devices could be augmented to deliver some user experiences comparable to those offered by fixed systems. A preliminary research that follows the CMCVR paradigm is also described.
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paper_title: Enhancing 3D Graphics on Mobile Devices by Image-Based Rendering

paper_content:

Compared to a personal computer, mobile devices typically have weaker processing power, less memory capacity, and lower resolution of display. While the former two factors are clearly disadvantages for 3D graphics applications running on mobile devices, the display factor could be turned into an advantage instead. However the traditional 3D graphics pipeline cannot take advantage of the smaller display because its run time depends mostly on the number of polygons to be rendered. In contrast, the run time of image-based rendering methods depends mainly on the display resolution. Therefore it is well suited for mobile devices. Furthermore, we may use the network connection to build a client-server framework, which allows us to integrate with nonimage-based rendering programs. We present our system framework and the experiment results on PocketPC® based devices in this work.
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paper_title: An accelerated remote graphics architecture for PDAS

paper_content:

A new category of devices, known as Personal Digital Assistant (PDA), has become increasingly widespread since the end of the nineties. A large number of software applications have been developed for PDAs, but high-quality 3D graphics still remain beyond the computational capability of these devices.This paper tackles this issue by proposing a generic solution for hardware-accelerated remote rendering on cluster. The rendering task is submitted to a PC/workstation cluster (each cluster machine is equipped by a graphics accelerator) by means of the Chromium architecture. Each machine renders a part of the image that is then reassembled and sent to the PDA via a software bridge. On the PDA side, the user can explore the scene using an ad-hoc navigation interface.The proposed solution allows to display extremely realistic and complex models in an interactive way. Moreover, our architecture does not depend on commercial solutions/products and can be easily modified in order to better fulfill requirements of specific applications.Computer GraphicsDistributed/network graphics Distributed SystemsDistributed applications
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paper_title: Recent Trends of Mobile Collaborative Augmented Reality Systems

paper_content:

The use of mobile collaborative AR has expended rapidly in recent years, due to the major advances in hardware and networking. The application areas are diverse and multidisciplinary. Recent Trends of Mobile Collaborative Augmented Reality Systems provides a historical overview of previous mobile collaborative AR systems, presents case studies of latest developments in current mobile collaborative AR systems, and latest technologies and system architectures used in this field. Recent Trends of Mobile Collaborative Augmented Reality Systems is designed for a professional audience composed of practitioners and researchers working in the field of augmented reality and human-computer interaction. Advanced-level students in computer science and electrical engineering focused on this topic will also find this book useful as a secondary text or reference.
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paper_title: A Mobile Vision System for Urban Detection with Informative Local Descriptors

paper_content:

We present a computer vision system for the detection and identification of urban objects from mobile phone imagery, e.g., for the application of tourist information services. Recognition is based on MAP decision making over weak object hypotheses from local descriptor responses in the mobile imagery. We present an improvement over the standard SIFT key detector [7] by selecting only informative (i-SIFT) keys for descriptor matching. Selection is applied first to reduce the complexity of the object model and second to accelerate detection by selective filtering. We present results on the MPG-20 mobile phone imagery with severe illumination, scale and viewpoint changes in the images, performing with ≈ 98% accuracy in identification, efficient (100%) background rejection, efficient (0%) false alarm rate, and reliable quality of service under extreme illumination conditions, significantly improving standard SIFT based recognition in every sense, providing - important for mobile vision - runtimes which are ≈ 8 (≈24) times faster for the MPG-20 (ZuBuD) database.
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paper_title: Plenoptic modeling: an image-based rendering system

paper_content:

Image-based rendering is a powerful new approach for generating real-time photorealistic computer graphics. It can provide convincing animations without an explicit geometric representation. We use the “plenoptic function” of Adelson and Bergen to provide a concise problem statement for image-based rendering paradigms, such as morphing and view interpolation. The plenoptic function is a parameterized function for describing everything that is visible from a given point in space. We present an image-based rendering system based on sampling, reconstructing, and resampling the plenoptic function. In addition, we introduce a novel visible surface algorithm and a geometric invariant for cylindrical projections that is equivalent to the epipolar constraint defined for planar projections.
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paper_title: ThinkAir: Dynamic resource allocation and parallel execution in the cloud for mobile code offloading

paper_content:

Smartphones have exploded in popularity in recent years, becoming ever more sophisticated and capable. As a result, developers worldwide are building increasingly complex applications that require ever increasing amounts of computational power and energy. In this paper we propose ThinkAir, a framework that makes it simple for developers to migrate their smartphone applications to the cloud. ThinkAir exploits the concept of smartphone virtualization in the cloud and provides method-level computation offloading. Advancing on previous work, it focuses on the elasticity and scalability of the cloud and enhances the power of mobile cloud computing by parallelizing method execution using multiple virtual machine (VM) images. We implement ThinkAir and evaluate it with a range of benchmarks starting from simple micro-benchmarks to more complex applications. First, we show that the execution time and energy consumption decrease two orders of magnitude for a N-queens puzzle application and one order of magnitude for a face detection and a virus scan application. We then show that a parallelizable application can invoke multiple VMs to execute in the cloud in a seamless and on-demand manner such as to achieve greater reduction on execution time and energy consumption. We finally use a memory-hungry image combiner tool to demonstrate that applications can dynamically request VMs with more computational power in order to meet their computational requirements.
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paper_title: Graphics Processing Units for Handhelds

paper_content:

During the past few years, mobile phones and other handheld devices have gone from only handling dull text-based menu systems to, on an increasing number of models, being able to render high-quality three-dimensional graphics at high frame rates. This paper is a survey of the special considerations that must be taken when designing graphics processing units (GPUs) on such devices. Starting off by introducing desktop GPUs as a reference, the paper discusses how mobile GPUs are designed, often with power consumption rather than performance as the primary goal. Lowering the bus traffic between the GPU and the memory is an efficient way of reducing power consumption, and therefore some high-level algorithms for bandwidth reduction are presented. In addition, an overview of the different APIs that are used in the handheld market to handle both two-dimensional and three-dimensional graphics is provided. Finally, we present our outlook for the future and discuss directions of future research on handheld GPUs.
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paper_title: Signature-based workload estimation for mobile 3D graphics

paper_content:

Until recently, most 3D graphics applications had been regarded as too computationally intensive for devices other than desktop computers and gaming consoles. This notion is rapidly changing due to improving screen resolutions and computing capabilities of mass-market handheld devices such as cellular phones and PDAs. As the mobile 3D gaming industry is poised to expand, significant innovations are required to provide users with high-quality 3D experience under limited processing, memory and energy budgets that are characteristic of the mobile domain. Energy saving schemes such as dynamic voltage and frequency scaling (DVFS), as well as system-level power and performance optimization methods for mobile devices require accurate and fast workload prediction. In this paper, we address the problem of workload prediction for mobile 3D graphics. We propose and describe a signature-based estimation technique for predicting 3D graphics workloads. By analyzing a gaming benchmark, we show that monitoring specific parameters of the 3D pipeline provides better prediction accuracy over conventional approaches. We describe how signatures capture such parameters concisely to make accurate workload predictions. Signature-based prediction is computationally efficient because first, signatures are compact, and second, they do not require elaborate model evaluations. Thus, they are amenable to efficient, real-time prediction. A fundamental difference between signatures and standard history-based predictors is that signatures capture previous outcomes as well as the cause that led to the outcome, and use both to predict future outcomes. We illustrate the utility of signature-based workload estimation technique by using it as a basis for DVFS in 3D graphics pipelines.
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paper_title: Low-power 3D graphics processors for mobile terminals

paper_content:

A full 3D graphics pipeline is investigated, and optimizations of graphics architecture are assessed for satisfying the performance requirements and overcoming the limited system resources found in mobile terminals. Two mobile 3D graphics processor architectures, RAMP and DigiAcc, are proposed based on the analysis, and a prototype development platform (REMY) is implemented. REMY includes a software graphics library and simulation environment developed for more flexible realization of mobile 3D graphics. The experimental results demonstrate the feasibility of mobile 3D graphics with 3.6 Mpolygons/s at 155 mW power consumption for full 3D operation.
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paper_title: Energy Management Techniques in Modern Mobile Handsets

paper_content:

Managing energy efficiently is paramount in modern smartphones. The diverse range of wireless interfaces and sensors, and the increasing popularity of power-hungry applications that take advantage of these resources can reduce the battery life of mobile handhelds to few hours of operation. The research community, and operating system and hardware vendors found interesting optimisations and techniques to extend the battery life of mobile phones. However, the state of the art of lithium-ion batteries clearly indicates that energy efficiency must be achieved both at the hardware and software level. In this survey, we will cover the software solutions that can be found in the research literature between 1999 and May 2011 at six different levels: energy-aware operating systems, efficient resource management, the impact of users' interaction patterns with mobile devices and applications, wireless interfaces and sensors management, and finally the benefits of integrating mobile devices with cloud computing services.
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paper_title: PCU: the programmable culling unit

paper_content:

Culling techniques have always been a central part of computer graphics, but graphics hardware still lack efficient and flexible support for culling. To improve the situation, we introduce the programmable culling unit, which is as flexible as the fragment program unit and capable of quickly culling entire blocks of fragments. Furthermore, it is very easy for the developer to use the PCU as culling programs can be automatically derived from fragment programs containing a discard instruction. Our PCU can be integrated into an existing fragment program unit with a modest hardware overhead of only about 10%. Using the PCU, we have observed shader speedups between 1.4 and 2.1 for relevant scenes.
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paper_title: Using mobile GPU for general-purpose computing – a case study of face recognition on smartphones

paper_content:

As GPU becomes an integrated component in handheld devices like smartphones, we have been investigating the opportunities and limitations of utilizing the ultra-low-power GPU in a mobile platform as a general-purpose accelerator, similar to its role in desktop and server platforms. The special focus of our investigation has been on mobile GPU's role for energy-optimized real-time applications running on battery-powered handheld devices. In this work, we use face recognition as an application driver for our study. Our implementations on a smartphone reveals that, utilizing the mobile GPU as a co-processor can achieve significant speedup in performance as well as substantial reduction in total energy consumption, in comparison with a mobile-CPU-only implementation on the same platform.
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paper_title: An adaptive training-free feature tracker for mobile phones

paper_content:

While tracking technologies based on fiducial markers have dominated the development of Augmented Reality (AR) applications for almost a decade, various real-time capable approaches to markerless tracking have recently been presented. However, most existing approaches do not yet achieve sufficient frame rates for AR on mobile phones or at least require an extensive training phase in advance. In this paper we will present our approach on feature based tracking applying robust SURF features. The implementation is more than one magnitude faster than previous ones, allowing running even on mobile phones at highly interactive rates. In contrast to other feature based approaches on mobile phones, our implementation may immediately track features captured from a photo without any training. Further, the approach is not restricted to planar surfaces, but may use features of 3D objects.
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paper_title: Graphics Processing Units for Handhelds

paper_content:

During the past few years, mobile phones and other handheld devices have gone from only handling dull text-based menu systems to, on an increasing number of models, being able to render high-quality three-dimensional graphics at high frame rates. This paper is a survey of the special considerations that must be taken when designing graphics processing units (GPUs) on such devices. Starting off by introducing desktop GPUs as a reference, the paper discusses how mobile GPUs are designed, often with power consumption rather than performance as the primary goal. Lowering the bus traffic between the GPU and the memory is an efficient way of reducing power consumption, and therefore some high-level algorithms for bandwidth reduction are presented. In addition, an overview of the different APIs that are used in the handheld market to handle both two-dimensional and three-dimensional graphics is provided. Finally, we present our outlook for the future and discuss directions of future research on handheld GPUs.
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paper_title: Extraction of Natural Feature Descriptors on Mobile GPUs

paper_content:

In this thesis the feasibility of a GPGPU (general-purpose computing on graphics processing units) approach to natural feature description on mobile phone GPUs is assessed. To this end, the SURF descriptor [4] has been implemented with OpenGL ES 2.0/GLSL ES 1.0 and evaluated across different mobile devices. The implementation is multiple times faster than a comparable CPU variant on the same device. The results proof the feasibility of modern mobile graphics accelerators for GPGPU tasks especially for the detection phase in natural feature tracking used in augmented reality applications. Extensive analysis and benchmarking of this approach in comparison to state of the art methods have been undertaken. Insights into the modifications necessary to adapt and modify the SURF algorithm to the limitations of a mobile GPU are presented. Further, an outlook for a GPGPU-based tracking pipeline on a mobile device is provided.
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paper_title: PhoneGuide: museum guidance supported by on-device object recognition on mobile phones

paper_content:

We present PhoneGuide -- an enhanced museum guidance system that uses camera-equipped mobile phones and on-device object recognition.Our main technical achievement is a simple and light-weight object recognition approach that is realized with single-layer perceptron neuronal networks. In contrast to related systems which perform computationally intensive image processing tasks on remote servers, our intention is to carry out all computations directly on the phone. This ensures little or even no network traffic and consequently decreases cost for online times. Our laboratory experiments and field surveys have shown that photographed museum exhibits can be recognized with a probability of over 90%.We have evaluated different feature sets to optimize the recognition rate and performance. Our experiments revealed that normalized color features are most effective for our method. Choosing such a feature set allows recognizing an object below one second on up-to-date phones. The amount of data that is required for differentiating 50 objects from multiple perspectives is less than 6KBytes.
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paper_title: Archeoguide: system architecture of a mobile outdoor augmented reality system

paper_content:

We present the system architecture of a mobile outdoor augmented reality system for the Archeoguide project. We begin with a short introduction to the project. Then we present the hardware we chose for the mobile system and we describe the system architecture we designed for the software implementation. We conclude this paper with the first results obtained from experiments we made during our trials at ancient Olympia in Greece.
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paper_title: 3DVN: A Mixed Reality Platform for Mobile Navigation Assistance

paper_content:

We present 3DVN, a Mixed Reality platform for navigation assistance in indoor environments. Built on top of a PC-based wearable computer running the Windows operating system, the platform provides a multimodal user interface for navigating in existing physical buildings, including wireless networking, data glove gestural input, voice communication, head-mounted display, and a 3DOF head tracker. Local positioning is performed using a software-only positioning engine making use of WLAN features for accurately pinpointing the mobile device in three dimensions. The 3DVN system has been implemented as a proof-of-concept of a navigation guidance support device for visitors, and has been field-tested with human subjects in the student center of our university. Informal evaluation of subject ratings indicate a strong interest for the new system, both for guests as well as people familiar with the campus and the building.
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paper_title: User Interface Management Techniques for Collaborative Mobile Augmented Reality

paper_content:

Mobile Augmented Reality Systems (MARS) have the potential to revolutionize the way in which information is provided to users. Virtual information can be directly integrated with the real world surrounding the mobile user, who can interact with it to display related information, to pose and resolve queries, and to collaborate with other users. However, we believe that the benefits of MARS will only be achieved if the user interface (UI) is actively managed so as to maximize the relevance and minimize the confusion of the virtual material relative to the real world. This article addresses some of the steps involved in this process, focusing on the design and layout of the mobile user’s overlaid virtual environment. The augmented view of the user’s surroundings presents an interface to context-dependent operations, many of which are related to the objects in view—the augmented world is the user interface. We present three user interface design techniques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view management. Information filtering helps select the most relevant information to present to the user. UI component designdetermines the format in which this information should be conveyed, based on the available display resources and tracking accuracy. For example, the absence of high accuracy position tracking would favor body- or screenstabilized components over world-stabilized ones that would need to be exactly registered with the physical objects to which they refer. View management attempts to ensure that the virtual objects that are displayed visually are arranged appropriately with regard to their projections on the view plane. For example, the relationships among objects should be as unambiguous as possible, and physical or virtual objects should not obstruct the user’s view of more important physical or virtual objects in the scene. We illustrate these interface design techniques using our prototype collaborative, cross-site MARS environment, which is composed of mobile and non-mobile augmented reality and virtual reality systems.
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paper_title: Face to face collaborative AR on mobile phones

paper_content:

Mobile phones are an ideal platform for augmented reality. In this paper we describe how they also can be used to support face to face collaborative AR applications. We have created a custom port of the ARToolKit library to the Symbian mobile phone operating system and then developed a sample collaborative AR game based on this. We describe the game in detail and user feedback from people who have played it. We also provide general design guidelines that could be useful for others who are developing mobile phone collaborative AR applications.
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paper_title: Mobile Collaborative Augmented Reality: the Augmented Stroll

paper_content:

The paper focuses on Augmented Reality systems in which interaction with the real world is augmented by the computer, the task being performed in the real world. We first define what mobile AR systems, collaborative AR systems and finally mobile and collaborative AR systems are. We then present the augmented stroll and its software design as one example of a mobile and collaborative AR system. The augmented stroll is applied to Archaeology in the MAGIC (Mobile Augmented Group Interaction in Context) project.
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paper_title: Like bees around the hive: a comparative study of a mobile augmented reality map

paper_content:

We present findings from field trials of MapLens, a mobile augmented reality (AR) map using a magic lens over a paper map. Twenty-six participants used MapLens to play a location-based game in a city centre. Comparisons to a group of 11 users with a standard 2D mobile map uncover phenomena that arise uniquely when interacting with AR features in the wild. The main finding is that AR features facilitate place-making by creating a constant need for referencing to the physical, and in that it allows for ease of bodily configurations for the group, encourages establishment of common ground, and thereby invites discussion, negotiation and public problem-solving. The main potential of AR maps lies in their use as a collaborative tool.
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paper_title: Human pacman: A mobile entertainment system with ubiquitous computing and tangible interaction over a wide outdoor area

paper_content:

Human Pacman is an interactive role-playing game that envisions to bring the computer gaming experience to a new level of emotional and sensory gratification by setting the real world as a playground. This is a physical fantasy game integrated with human-social and mobile-gaming that emphasizes on collaboration and competition between players. By setting the game in a wide outdoor area, natural human-physical movements have become an integral part of the game. Pacmen and Ghosts are now human players in the real world experiencing mixed reality visualization from the wearable computers on them. Virtual cookies and actual physical objects are incorporated to provide novel experiences of seamless transitions between real and virtual worlds and tangible human computer interface respectively. We believe Human Pacman is pioneering a new form of gaming that anchors on physicality, mobility, social interaction, and ubiquitous computing.
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paper_title: Mystery at the Museum – A Collaborative Game for Museum Education

paper_content:

Through an iterative design process involving museum educators, learning scientists and technologists, and drawing upon our previous experiences in handheld game design and a growing body of knowledge on learning through gaming, we designed an interactive mystery game called Mystery at the Museum (the High Tech Whodunnit), which was designed for synchronous play of groups of parents and children over a two to three hour period. The primary design goals were to engage visitors more deeply in the museum, engage visitors more broadly across museum exhibits, and encourage collaboration between visitors. The feedback from the participants suggested that the combination of depth and breadth was engaging and effective in encouraging them to think about the museum's exhibits. The roles that were an integral part of the game turned out to be extremely effective in engaging pairs of participants with one another. Feedback from parents was quite positive in terms of how they felt it engaged them and their children. These results suggest that further explorations of technology-based museum experiences of this type are wholly appropriate.
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paper_title: Mixed reality training application for an oil refinery: user requirements

paper_content:

Introducing mixed reality (MR) into safety-critical environment like oil refinery is difficult, since the environment and organization lays demanding restrictions for the application. In order to develop usable and safe MR application, we need to study the context of use and derive user requirements from it. This paper describes the user requirements for an MR based oil refinery training tool. The application is aimed to train employees of a specific process unit in the refinery. Training is currently done mainly in a classroom and on-site only when the process is closed down. On-site training is necessary, but expensive and rarely possible. The use of mixed reality offers a way to train employees on-site while the process is running. Users can virtually see "inside" the columns and can modify virtually the process.
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paper_title: BARS: Battlefield Augmented Reality System

paper_content:

Abstract : Situational awareness needs cannot be met using traditional approaches such as radios, maps and handheld displays and more powerful display paradigms are needed. We are researching mobile augmented reality (AR) through the development of the Battlefield Augmented Reality System (BARS) in collaboration with Columbia University. The system consists of a wearable computer a wireless network system and a tracked see-through Head Mounted Display (HMD). The user's perception of the environment is enhanced by superimposing graphics onto the user's field of view. The graphics are registered (aligned) with the actual environment. For example an augmented view of a building could include a wireframe plan of its interior icons to represent reported locations of snipers and the names of adjacent streets.
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paper_title: Augmented reality in the psychomotor phase of a procedural task

paper_content:

Procedural tasks are common to many domains, ranging from maintenance and repair, to medicine, to the arts. We describe and evaluate a prototype augmented reality (AR) user interface designed to assist users in the relatively under-explored psychomotor phase of procedural tasks. In this phase, the user begins physical manipulations, and thus alters aspects of the underlying task environment. Our prototype tracks the user and multiple components in a typical maintenance assembly task, and provides dynamic, prescriptive, overlaid instructions on a see-through head-worn display in response to the user's ongoing activity. A user study shows participants were able to complete psychomotor aspects of the assembly task significantly faster and with significantly greater accuracy than when using 3D-graphics-based assistance presented on a stationary LCD. Qualitative questionnaire results indicate that participants overwhelmingly preferred the AR condition, and ranked it as more intuitive than the LCD condition.
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paper_title: In-Place Sketching for content authoring in Augmented Reality games

paper_content:

Sketching leverages human skills for various purposes. In-Place Augmented Reality Sketching experiences build on the intuitiveness and flexibility of hand sketching for tasks like content creation. In this paper we explore the design space of In-Place Augmented Reality Sketching, with particular attention to content authoring in games. We propose a contextual model that offers a framework for the exploration of this design space by the research community. We describe a sketch-based AR racing game we developed to demonstrate the proposed model. The game is developed on top of our shape recognition and 3D registration library for mobile AR.
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paper_title: Augmented assembly using a mobile phone

paper_content:

We present a mobile phone based augmented reality (AR) assembly system that enable users to view complex models on their mobile phones. It is based on a client-server architecture, where complex model information is located on a PC, and a mobile phone with the camera is used as a thin client access device to this information. With this system users are able to see an AR view that provides step by step guidance for a real world assembly task. We also present results from a pilot user study evaluating the system, showing that people felt the interface was intuitive and very helpful in supporting the assembly task.
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paper_title: Comparative effectiveness of augmented reality in object assembly

paper_content:

Although there has been much speculation about the potential of Augmented Reality (AR), there are very few empirical studies about its effectiveness. This paper describes an experiment that tested the relative effectiveness of AR instructions in an assembly task. Task information was displayed in user's field of view and registered with the workspace as 3D objects to explicitly demonstrate the exact execution of a procedure step. Three instructional media were compared with the AR system: a printed manual, computer assisted instruction (CAI) using a monitor-based display, and CAI utilizing a head-mounted display. Results indicate that overlaying 3D instructions on the actual work pieces reduced the error rate for an assembly task by 82%, particularly diminishing cumulative errors - errors due to previous assembly mistakes. Measurement of mental effort indicated decreased mental effort in the AR condition, suggesting some of the mental calculation of the assembly task is offloaded to the system.
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paper_title: Mobile phone based AR scene assembly

paper_content:

In this paper we describe a mobile phone based Augmented Reality application for 3D scene assembly. Augmented Reality on mobile phones extends the interaction capabilities on such handheld devices. It adds a 6 DOF isomorphic interaction technique for manipulating 3D content. We give details of an application that we believe to be the first where 3D content can be manipulated using both the movement of a camera tracked mobile phone and a traditional button interface as input for transformations. By centering the scene in a tangible marker space in front of the phone we provide a mean for bimanual interaction. We describe the implementation, the interaction techniques we have developed and initial user response to trying the application.
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paper_title: Mobile augmented reality in the data center

paper_content:

Recent advances in compute power, graphics power, and cameras in mobile computing devices have facilitated the development of new augmented reality applications in the mobile device space. Mobile augmented reality provides a straightforward and natural way for users to understand complex data by overlaying visualization on top of a live video feed on their mobile device. In our data center mobile augmented reality project, the user points a mobile device camera at a rack of data center assets, and additional content about these assets is visually overlaid on top of each asset in the video stream from the mobile device camera. This correspondence between digital content and physical things or locations makes mobile augmented reality an intuitive user interface for interacting with the world around us. This paper describes augmented reality techniques for mobile devices and the motivations around using a multimarker computer vision-based technique for visualizing asset data in the data center. Our mobile augmented reality project enables system administrators to easily interact with hardware assets while they are in the data center, providing them with an additional tool to use in managing the data center.
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paper_title: Combination of UWB and GPS for indoor-outdoor vehicle localization

paper_content:

GPS receivers are satellite-based devices widely used for vehicle localization that, given their limitations, are not suitable for performing within indoor or dense urban environments. On the other hand ultra-wide band (UWB), a technology used for efficient wireless communication, has recently being used for vehicle localization in indoor environments with promising results. This paper focuses on the combination of both technologies for accurate positioning of vehicles in a mixed scenario (both indoor and outdoor situations), which is typical in some industrial applications. Our approach is based on combining sensor information in a Monte Carlo localization algorithm (also known as particle Filter), which has revealed its suitability for probabilistically coping with a variety of sensory data. The performance of our approach has been satisfactorily tested on a real robot, endowed with a UWB master antenna and a GPS receiver, within an indoor-outdoor scenario where three UWB slave antennas were placed in the indoor area.
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paper_title: Virtual Vouchers: Prototyping a Mobile Augmented Reality User Interface for Botanical Species Identification

paper_content:

the tools that botanists require for field-work must evolve and take on new forms. Of particular importance is the ability to identify existing and new species in the field. Mobile augmented reality systems can make it possible to access, view, and inspect a large database of virtual species examples side-by-side with physical specimens. In this paper, we present prototypes of a mobile augmented reality electronic field guide and techniques for displaying and inspecting computer vision-based visual search results in the form of virtual vouchers. Our work addresses head-movement controlled augmented reality for hands-free interaction and tangible augmented reality. We describe results from our design and investigation process and discuss observations and feedback from lab trials by botanists.
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paper_title: User Interface Management Techniques for Collaborative Mobile Augmented Reality

paper_content:

Mobile Augmented Reality Systems (MARS) have the potential to revolutionize the way in which information is provided to users. Virtual information can be directly integrated with the real world surrounding the mobile user, who can interact with it to display related information, to pose and resolve queries, and to collaborate with other users. However, we believe that the benefits of MARS will only be achieved if the user interface (UI) is actively managed so as to maximize the relevance and minimize the confusion of the virtual material relative to the real world. This article addresses some of the steps involved in this process, focusing on the design and layout of the mobile user’s overlaid virtual environment. The augmented view of the user’s surroundings presents an interface to context-dependent operations, many of which are related to the objects in view—the augmented world is the user interface. We present three user interface design techniques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view management. Information filtering helps select the most relevant information to present to the user. UI component designdetermines the format in which this information should be conveyed, based on the available display resources and tracking accuracy. For example, the absence of high accuracy position tracking would favor body- or screenstabilized components over world-stabilized ones that would need to be exactly registered with the physical objects to which they refer. View management attempts to ensure that the virtual objects that are displayed visually are arranged appropriately with regard to their projections on the view plane. For example, the relationships among objects should be as unambiguous as possible, and physical or virtual objects should not obstruct the user’s view of more important physical or virtual objects in the scene. We illustrate these interface design techniques using our prototype collaborative, cross-site MARS environment, which is composed of mobile and non-mobile augmented reality and virtual reality systems.
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paper_title: APRIL: a high-level framework for creating augmented reality presentations

paper_content:

While augmented reality (AR) technology is steadily maturing, application development is still lacking advanced authoring tools - even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for the structuring of AR content. In this paper we present APRIL, the Augmented Presentation and Interaction Language, an authoring platform for AR presentations which provides concepts and techniques that are independent of specific applications or target hardware platforms, and should be suitable to raise the level of abstraction on which AR content creators can operate.
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paper_title: An Augmented Reality System for MR Image – guided Needle Biopsy : Initial Results in a Swine Model 1

paper_content:

Purpose: To evaluate an augmented reality (AR) system in combination with a 1.5-T closed-bore magnetic resonance (MR) imager as a navigation tool for needle biopsies. Materials and Methods: The experimental protocol had institutional animal care and use committee approval. Seventy biopsies were performed in phantoms by using 20 tube targets, each with a diameter of 6 mm, and 50 virtual targets. The position of the needle tip in AR and MR space was compared in multiple imaging planes, and virtual and real needle tip localization errors were calculated. Ten AR-guided biopsies were performed in three pigs, and the duration of each procedure was determined. After successful puncture, the distance to the target was measured on MR images. The confidence limits for the achieved in-plane hit rate and for lateral deviation were calculated. A repeated measures analysis of variance was used to determine whether the placement error in a particular dimension (x, y, or z) differed from the others. Results: For the 50 v...
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paper_title: BARS: Battlefield Augmented Reality System

paper_content:

Abstract : Situational awareness needs cannot be met using traditional approaches such as radios, maps and handheld displays and more powerful display paradigms are needed. We are researching mobile augmented reality (AR) through the development of the Battlefield Augmented Reality System (BARS) in collaboration with Columbia University. The system consists of a wearable computer a wireless network system and a tracked see-through Head Mounted Display (HMD). The user's perception of the environment is enhanced by superimposing graphics onto the user's field of view. The graphics are registered (aligned) with the actual environment. For example an augmented view of a building could include a wireframe plan of its interior icons to represent reported locations of snipers and the names of adjacent streets.
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paper_title: Collaborative use of mobile augmented reality with paper maps

paper_content:

The popularity of augmented reality (AR) applications on mobile devices is increasing, but there is as yet little research on their use in real-settings. We review data from two pioneering field trials where MapLens, a magic lens that augments paper-based city maps, was used in small-group collaborative tasks. The first study compared MapLens to a digital version akin to Google Maps, the second looked at using one shared mobile device vs. using multiple devices. The studies find place-making and use of artefacts to communicate and establish common ground as predominant modes of interaction in AR-mediated collaboration with users working on tasks together despite not needing to.
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paper_title: Like bees around the hive: a comparative study of a mobile augmented reality map

paper_content:

We present findings from field trials of MapLens, a mobile augmented reality (AR) map using a magic lens over a paper map. Twenty-six participants used MapLens to play a location-based game in a city centre. Comparisons to a group of 11 users with a standard 2D mobile map uncover phenomena that arise uniquely when interacting with AR features in the wild. The main finding is that AR features facilitate place-making by creating a constant need for referencing to the physical, and in that it allows for ease of bodily configurations for the group, encourages establishment of common ground, and thereby invites discussion, negotiation and public problem-solving. The main potential of AR maps lies in their use as a collaborative tool.
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paper_title: Mobile phone based AR scene assembly

paper_content:

In this paper we describe a mobile phone based Augmented Reality application for 3D scene assembly. Augmented Reality on mobile phones extends the interaction capabilities on such handheld devices. It adds a 6 DOF isomorphic interaction technique for manipulating 3D content. We give details of an application that we believe to be the first where 3D content can be manipulated using both the movement of a camera tracked mobile phone and a traditional button interface as input for transformations. By centering the scene in a tangible marker space in front of the phone we provide a mean for bimanual interaction. We describe the implementation, the interaction techniques we have developed and initial user response to trying the application.
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paper_title: InfoSPOT: A mobile Augmented Reality method for accessing building information through a situation awareness approach

paper_content:

article i nfo Article history: Accepted 9 September 2012 Available online 6 October 2012 The Architecture, Engineering, Construction, and Owner/Operator (AECO) industry is constantly searching for new methods for increasing efficiency and productivity. Facility Managers (FMs), as a part of the owner/ operator role, work in complex and dynamic environments where critical decisions are constantly made. This decision-making process and its consequent performance can be improved by enhancing Situation Awareness (SA) of the FMs through new digital technologies. In this paper, InfoSPOT (Information Surveyed Point for Observation and Tracking), is recommended to FMs as a mobile Augmented Reality (AR) tool for accessing information about the facilities they maintain. AR has been considered as a viable option to reduce inefficiencies of data overload by providing FMs with a SA-based tool for visualizing their "real-world" envi- ronment with added interactive data. A prototype of the AR application was developed and a user participa- tion experiment and analysis conducted to evaluate the features of InfoSPOT. This innovative application of AR has the potential to improve construction practices, and in this case, facility management. Published by Elsevier B.V.
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paper_title: Combination of UWB and GPS for indoor-outdoor vehicle localization

paper_content:

GPS receivers are satellite-based devices widely used for vehicle localization that, given their limitations, are not suitable for performing within indoor or dense urban environments. On the other hand ultra-wide band (UWB), a technology used for efficient wireless communication, has recently being used for vehicle localization in indoor environments with promising results. This paper focuses on the combination of both technologies for accurate positioning of vehicles in a mixed scenario (both indoor and outdoor situations), which is typical in some industrial applications. Our approach is based on combining sensor information in a Monte Carlo localization algorithm (also known as particle Filter), which has revealed its suitability for probabilistically coping with a variety of sensory data. The performance of our approach has been satisfactorily tested on a real robot, endowed with a UWB master antenna and a GPS receiver, within an indoor-outdoor scenario where three UWB slave antennas were placed in the indoor area.
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paper_title: Recent Advances in Augmented Reality

paper_content:

In 1997, Azuma published a survey on augmented reality (AR). Our goal is to complement, rather than replace, the original survey by presenting representative examples of the new advances. We refer one to the original survey for descriptions of potential applications (such as medical visualization, maintenance and repair of complex equipment, annotation, and path planning); summaries of AR system characteristics (such as the advantages and disadvantages of optical and video approaches to blending virtual and real, problems in display focus and contrast, and system portability); and an introduction to the crucial problem of registration, including sources of registration error and error-reduction strategies.
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Title: Mobile Augmented Reality Survey: A Bottom-Up Approach

Section 1: INTRODUCTION
Description 1: Provide an overview of advancements in mobile technology enabling AR, definition of Mobile Augmented Reality (MAR), and the unique challenges faced by MAR systems.

Section 2: Mobile Computing Platforms
Description 2: Discuss various mobile computing platforms used in MAR, including notebook computers, PDAs, tablet PCs, UMPCs, mobile phones, and AR glasses, along with their advantages and disadvantages.

Section 3: Software Frameworks
Description 3: Review different software frameworks developed to ease MAR system development, such as Studierstube ES, Nexus, UMAR, Tinmith-evo5, DWARF, KHARMA, and ALVAR.

Section 4: Display Devices
Description 4: Analyze various display devices for MAR, including Optical See-through Displays, Video See-through Displays, and Surface Projection Displays, including their functionalities and limitations.

Section 5: Tracking and Registration
Description 5: Examine tracking and registration methods for MAR, categorizing them into sensor-based methods (inertial, magnetic, electromagnetic, ultrasonic) and vision-based methods (marker-based, natural feature), as well as hybrid methods for better accuracy.

Section 6: Wireless Networks
Description 6: Evaluate wireless network technologies utilized in MAR for pose tracking and data communication, including WWAN, WLAN, and WPAN.

Section 7: Data Management
Description 7: Explore strategies for efficient data management in MAR applications, including data acquisition, data modeling, and data storage techniques.

Section 8: SYSTEM PERFORMANCE AND SUSTAINABILITY
Description 8: Discuss the challenges related to runtime performance and energy efficiency in MAR systems, along with methods for improving performance through multicore CPU parallelism, GPU computing, cache optimization, memory bandwidth saving, and computation outsourcing.

Section 9: Application Fields
Description 9: Survey various fields where MAR applications are used, such as tourism and navigation, entertainment and advertisement, training and education, assembly and maintenance, information assistant management, and more.

Section 10: Technology Limitations
Description 10: Identify technological limitations faced by MAR applications, such as privacy and security concerns, application breakthroughs needed, over-emphasized self-support, and social acceptance challenges.

Section 11: CONCLUSIONS
Description 11: Summarize key points discussed in the paper, highlight the potential of MAR technology, and speculate on future trends and developments, particularly the role of mobile cloud computing and dedicated MAR devices.