A Review on posture monitoring systems
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paper_title: Implementation of Sitting Posture Monitoring System with Kinect

paper_content:

Most modern office workers are seated on the chair for working with the computer during most working time. Generally, the correct sitting posture is critical for human life because wrong sitting posture can lead the back or neck disorder related sickness. The majority of previous researches have been utilized various sensors with special chairs to measure the sitting posture. However, these special chairs can be uncomfortable for users due to unfamiliar sitting environment. Therefore, we proposed the sitting posture monitoring system using Kinect which provides IR depth camera to record user’s sitting posture data and alert wrong posture to user. The proposed system provided 62% increased correct sitting posture during 35 min for 5 participants. We believe that the proposed system can help to improve the behavior of sitting posture of user without any uncomfortable adhesive sensors.
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paper_title: The effectiveness of a training method using self-modeling webcam photos for reducing musculoskeletal risk among office workers using computers

paper_content:

Abstract An intervention study was conducted to examine the effectiveness of an innovative self-modeling photo-training method for reducing musculoskeletal risk among office workers using computers. Sixty workers were randomly assigned to either: 1) a control group; 2) an office training group that received personal, ergonomic training and workstation adjustments or 3) a photo-training group that received both office training and an automatic frequent-feedback system that displayed on the computer screen a photo of the worker’s current sitting posture together with the correct posture photo taken earlier during office training. Musculoskeletal risk was evaluated using the Rapid Upper Limb Assessment (RULA) method before, during and after the six weeks intervention. Both training methods provided effective short-term posture improvement; however, sustained improvement was only attained with the photo-training method. Both interventions had a greater effect on older workers and on workers suffering more musculoskeletal pain. The photo-training method had a greater positive effect on women than on men.
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paper_title: Vision-based patient monitoring: a comprehensive review of algorithms and technologies

paper_content:

Vision-based monitoring for assisted living is gaining increasing attention, especially in multi-modal monitoring systems owing to the several advantages of vision-based sensors. In this paper, a detailed survey of some of the important vision-based patient monitoring applications is presented, namely (a) fall detection (b) action and activity monitoring (c) sleep monitoring (d) respiration and apnea monitoring (e) epilepsy monitoring (f) vital signs monitoring and (g) facial expression monitoring. The challenges and state-of-art technologies in each of these applications is presented. This is the first work to present such a comprehensive survey with the focus on a set of seven most common applications pertaining to patient monitoring. Potential future directions are presented while also considering practical large scale deployment of vision-based systems in patient monitoring. One of the important conclusions drawn is that rather than applying generic algorithms, use of the application context of patient monitoring can be a useful way to develop novel techniques that are robust and yet cost-effective.
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paper_title: Smart Chair: What Can Simple Pressure Sensors under the Chairs' Legs Tell Us about User Activity?

paper_content:

In this paper, we investigate how much information about user activity can be extracted from simple pressure sensors mounted under the legs of a chair. We show that it is possible to detect not only different postures (0.826 accuracy for 5 subjects and 7 classes), but also subtle hand and head related actions like typing and nodding (0.880 accuracy for 5 subjects and 5 classes). Combining features related to postures and such simple actions, we can detect high-level activities such as working on a PC, watching a movie or eating in a continuous, real-life data stream. In a dataset of 105.6 hours recorded from 4 subjects, we achieved 0.783 accuracy for 7 classes. Keywords—ubiquitous computing; smart chair; resistive pres- sure sensor; activity recognition
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paper_title: Sitting Posture Monitoring System Based on a Low-Cost Load Cell Using Machine Learning

paper_content:

Sitting posture monitoring systems (SPMSs) help assess the posture of a seated person in real-time and improve sitting posture. To date, SPMS studies reported have required many sensors mounted on the backrest plate and seat plate of a chair. The present study, therefore, developed a system that measures a total of six sitting postures including the posture that applied a load to the backrest plate, with four load cells mounted only on the seat plate. Various machine learning algorithms were applied to the body weight ratio measured by the developed SPMS to identify the method that most accurately classified the actual sitting posture of the seated person. After classifying the sitting postures using several classifiers, average and maximum classification rates of 97.20% and 97.94%, respectively, were obtained from nine subjects with a support vector machine using the radial basis function kernel; the results obtained by this classifier showed a statistically significant difference from the results of multiple classifications using other classifiers. The proposed SPMS was able to classify six sitting postures including the posture with loading on the backrest and showed the possibility of classifying the sitting posture even though the number of sensors is reduced.
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paper_title: Industrial Robot Tool Position Estimation using Inertial Measurements in a Complementary Filter and an EKF

paper_content:

In this work an Inertial Measurement Unit is used to improve tool position estimates for an ABB IRB 4600 industrial robot, starting from estimates based on motor angle forward kinematics. A Comple ...
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paper_title: Applications of inertial sensors in medicine: towards model-based rehabilitation of stroke

paper_content:

Abstract Present work introduces to the concept of a quantitative assessment of stroke rehabilitation using an inverse dynamical analysis and inertial sensors for measurement of motor functions in a clinical setting. The application in medicine gives possibilities to evaluate quantitatively damaged motor functions via instrumented analysis thus proposing an additional tool for monitoring of rehabilitation process with a larger accuracy. The paper presents a simplified dynamical model of an upper extremity which allows estimating joint torques via inverse dynamics from measured arm's kinematics. The model serves as an initial step going towards patient-specific model-based rehabilitation in the future.
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paper_title: Trunk posture monitoring with inertial sensors

paper_content:

Measurement of human posture and movement is an important area of research in the bioengineering and rehabilitation fields. Various attempts have been initiated for different clinical application goals, such as diagnosis of pathological posture and movements, assessment of pre- and post-treatment efficacy and comparison of different treatment protocols. Image-based methods for measurements of human posture and movements have been developed, such as the radiography, photogrammetry, optoelectric technique and video analysis. However, it is found that these methods are complicated to set up, time-consuming to operate and could only be applied in laboratory environments. This study introduced a method of using a posture monitoring system in estimating the spinal curvature changes during trunk movements on the sagittal and coronal planes and providing trunk posture monitoring during daily activities. The system consisted of three sensor modules, each with one tri-axial accelerometer and three uni-axial gyroscopes orthogonally aligned, and a digital data acquisition and feedback system. The accuracy of this system was tested with a motion analysis system (Vicon 370) in calibration with experimental setup and in trunk posture measurement with nine human subjects, and the performance of the posture monitoring system during daily activities with two human subjects was reported. The averaged root mean squared differences between the measurements of the system and motion analysis system were found to be 0.999 for dynamic calibration and >0.829 for estimation of spinal curvature change in domain planes of movement during flexion and lateral bending). With the sensing modules located on the upper trunk, mid-trunk and the pelvic levels, the inclination of trunk segment and the change of spinal curvature in trunk movements could be estimated. The posture information of five subjects was recorded at 30 s intervals during daily activity over a period of 3 days and 2 h a day. The preliminary results demonstrated that the subjects could improve their posture when feedback signals were provided. The posture monitoring system could be used for the purpose of posture monitoring during daily activity.
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paper_title: A wearable embedded device for chronic low back patients to track lumbar spine position

paper_content:

In present scenario, people always work in an enclosed environment where they sit in the bend posture that causes severe damage in lumbar spine. According to the survey of World Health Organization, around the world 500,000 to 800,000 people are suffering from spinal cord injury (SCI). In that about 53% of the people who are aged between 16 and 30 suffer from chronic low back pain. A new wearable device which consists of miniature gyroscope and accelerometer are used in detecting the voluntary action of lumbar spine in the proposed system. The proposed system consists of a vibrator, Bluetooth element, a microcontroller and an android application. The vibrator motor is used to intimate the improper sitting position of the person. A Bluetooth element is used in transmitting the data from the module and the android application that runs on smart phone. It records the analyzed data of the sensor. A microcontroller is used to control the overall working of the designed system. The capability of this cost effective, simple device is capable to measure the lumbar spine position with the efficiency of 95% and provide a feedback to the user.
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paper_title: Smart Rehabilitation Garment for posture monitoring

paper_content:

Posture monitoring and correction technologies can support prevention and treatment of spinal pain or can help detect and avoid compensatory movements during the neurological rehabilitation of upper extremities, which can be very important to ensure their effectiveness. We describe the design and development of Smart Rehabilitation Garment (SRG) a wearable system designed to support posture correction. The SRG combines a number of inertial measurement units (IMUs), controlled by an Arduino processor. It provides feedback with vibration on the garment, audible alarm signals and visual instruction through a Bluetooth connected smartphone. We discuss the placement of sensing modules, the garment design, the feedback design and the integration of smart textiles and wearable electronics which aimed at achieving wearability and ease of use. We report on the system's accuracy as compared to optical tracker method.
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paper_title: Flex sensor characterization against shape and curvature changes

paper_content:

Abstract Resistive flex sensors were increasingly used in different areas for their interesting property to change their resistance when bent. In particular, they can be applied to human segment in biomedical devices to register static and dynamic postures. In spite of their interesting properties, such as robustness, low price and long life, they often demonstrate non-linear response and lower sensitivity at small bending angles. This paper provides investigation to improve flex sensors linearity and sensitivity to measure body joint angles with better accuracy. To this aim, an empirical model of the sheet (or surface) resistance of the active layer, to simulate its behavior against the layer shape and size as well as the bending angle, was provided, to investigate whether changes of the standard rectangular shape can improve sensitivity and linearity. In addition, to date commercial flex sensors have been characterized only against the bending angle with a radius of curvature smaller than the device length, so limiting the application to small joints such as finger or knee. In order to extend the flex sensor applications, for instance, to measure the trunk posture in back disease and rehabilitation monitoring, the sensor response against a radius of curvature greater than the sensor length was analyzed. Finally, a new modeling technique, based on the inverse model of the sensor characteristic, to enable fast measurements of the bending angle or the radius of curvature from sensor response also in real time, and fast calibration procedures, fitting the same model to measurements with different joint size and even device, were developed.
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paper_title: Wearable Flexible Sensors: A Review

paper_content:

This paper provides a review on some of the significant research work done on wearable flexible sensors (WFSs). Sensors fabricated with the flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for the further analyses. The use of wearable sensors has played a quite important role to monitor the physiological parameters of a person to minimize any malfunctioning happening in the body. This paper categorizes the work according to the materials used for designing the system, the network protocols, and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the WFSs regarding its market values are also briefly explained in this paper.
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paper_title: Wireless Wearable T-Shirt for Posture Monitoring During Rehabilitation Exercises

paper_content:

The monitoring of any human physiological parameters during rehabilitation exercises requires noninvasive sensors for the patient. This paper describes a wireless wearable T-shirt for posture monitoring during rehabilitation or reinforcement exercises. The subject posture is measured through a sensorized T-shirt using an inductive sensor sewn directly on the fabric. The wireless wearable T-shirt design specifications are the following: independence from the remote unit, easy to use, lightweight and comfort of wearing. This paper reports the conceptual framework, the fabricated device description, and the adopted experimental setup. The instrumented T-shirt’s output data are compared with the data obtained via an optical system, as a gold standard, that measures the marker positions over the patient’s back and chest. The trials performed on four subjects obtained on different days demonstrate that the wireless wearable sensor described in this paper is capable of producing reliable data compared with the data obtained with the optical system. The constitutive sensor simplicity that includes only a copper wire and a separable circuit board allows achieving the objectives of simplicity, ease of use, and noninvasiveness. The sensorized T-shirt, integrated with designed conditioning and transmission electronics for remote communication, could be used as a support tool for postural monitoring during rehabilitation exercises.
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paper_title: A System for Wearable Monitoring of Seated Posture in Computer Users

paper_content:

This work describes the evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture, and the development of a workstation interface for the posture monitoring system. A garment-integrated POF sensor was developed and tested on nine healthy subjects. Data from the wearable sensor were compared to data taken simultaneously from a marker-based motion capture system. Peak analysis of the resulting data show a mean value error of 0.64 degrees and a mean time error of 0.53 seconds. These results show that the wearable sensor approximates the accuracy of expert visual analysis, and provides enough accuracy of measurement to reliably monitor seated spinal posture. The initial development of the system hardware and software inte rface are also described.
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paper_title: Real Time Monitoring of Posture to Improve Ergonomics

paper_content:

Back pain is one of humanities most frequent complaints. While dangerous diseases are being combatted on a daily basis, something as simple as bad posture is often overlooked. Bad posture can start off as a simple habit and soon lead to chronic back pain. Thus it is essential to maintain an ideal posture so as to reduce stress on the body. In this paper, monitoring of posture is done using flex sensor placed along the spine to detect the movement or bend. As posture changes from ‘ideal’ to ‘poor’, the user is alerted through a buzzer and LCD. A microcontroller is used to set the limits of ideal posture, which can be user specific. A load cell is used to monitor the variation in body weight and spine stress for poor and ideal postures under sitting and standing cases. The proposed system aims to implement a simple posture monitoring and correction system that can be set up at the work place with ease. This can serve to prevent cases of scoliosis and other spine issues which often start with poor posture.
---
paper_title: Flex sensor characterization against shape and curvature changes

paper_content:

Abstract Resistive flex sensors were increasingly used in different areas for their interesting property to change their resistance when bent. In particular, they can be applied to human segment in biomedical devices to register static and dynamic postures. In spite of their interesting properties, such as robustness, low price and long life, they often demonstrate non-linear response and lower sensitivity at small bending angles. This paper provides investigation to improve flex sensors linearity and sensitivity to measure body joint angles with better accuracy. To this aim, an empirical model of the sheet (or surface) resistance of the active layer, to simulate its behavior against the layer shape and size as well as the bending angle, was provided, to investigate whether changes of the standard rectangular shape can improve sensitivity and linearity. In addition, to date commercial flex sensors have been characterized only against the bending angle with a radius of curvature smaller than the device length, so limiting the application to small joints such as finger or knee. In order to extend the flex sensor applications, for instance, to measure the trunk posture in back disease and rehabilitation monitoring, the sensor response against a radius of curvature greater than the sensor length was analyzed. Finally, a new modeling technique, based on the inverse model of the sensor characteristic, to enable fast measurements of the bending angle or the radius of curvature from sensor response also in real time, and fast calibration procedures, fitting the same model to measurements with different joint size and even device, were developed.
---
paper_title: Wireless Wearable T-Shirt for Posture Monitoring During Rehabilitation Exercises

paper_content:

The monitoring of any human physiological parameters during rehabilitation exercises requires noninvasive sensors for the patient. This paper describes a wireless wearable T-shirt for posture monitoring during rehabilitation or reinforcement exercises. The subject posture is measured through a sensorized T-shirt using an inductive sensor sewn directly on the fabric. The wireless wearable T-shirt design specifications are the following: independence from the remote unit, easy to use, lightweight and comfort of wearing. This paper reports the conceptual framework, the fabricated device description, and the adopted experimental setup. The instrumented T-shirt’s output data are compared with the data obtained via an optical system, as a gold standard, that measures the marker positions over the patient’s back and chest. The trials performed on four subjects obtained on different days demonstrate that the wireless wearable sensor described in this paper is capable of producing reliable data compared with the data obtained with the optical system. The constitutive sensor simplicity that includes only a copper wire and a separable circuit board allows achieving the objectives of simplicity, ease of use, and noninvasiveness. The sensorized T-shirt, integrated with designed conditioning and transmission electronics for remote communication, could be used as a support tool for postural monitoring during rehabilitation exercises.
---
paper_title: A System for Wearable Monitoring of Seated Posture in Computer Users

paper_content:

This work describes the evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture, and the development of a workstation interface for the posture monitoring system. A garment-integrated POF sensor was developed and tested on nine healthy subjects. Data from the wearable sensor were compared to data taken simultaneously from a marker-based motion capture system. Peak analysis of the resulting data show a mean value error of 0.64 degrees and a mean time error of 0.53 seconds. These results show that the wearable sensor approximates the accuracy of expert visual analysis, and provides enough accuracy of measurement to reliably monitor seated spinal posture. The initial development of the system hardware and software inte rface are also described.
---
paper_title: Sitting Posture Monitoring System Based on a Low-Cost Load Cell Using Machine Learning

paper_content:

Sitting posture monitoring systems (SPMSs) help assess the posture of a seated person in real-time and improve sitting posture. To date, SPMS studies reported have required many sensors mounted on the backrest plate and seat plate of a chair. The present study, therefore, developed a system that measures a total of six sitting postures including the posture that applied a load to the backrest plate, with four load cells mounted only on the seat plate. Various machine learning algorithms were applied to the body weight ratio measured by the developed SPMS to identify the method that most accurately classified the actual sitting posture of the seated person. After classifying the sitting postures using several classifiers, average and maximum classification rates of 97.20% and 97.94%, respectively, were obtained from nine subjects with a support vector machine using the radial basis function kernel; the results obtained by this classifier showed a statistically significant difference from the results of multiple classifications using other classifiers. The proposed SPMS was able to classify six sitting postures including the posture with loading on the backrest and showed the possibility of classifying the sitting posture even though the number of sensors is reduced.
---
paper_title: Trunk posture monitoring with inertial sensors

paper_content:

Measurement of human posture and movement is an important area of research in the bioengineering and rehabilitation fields. Various attempts have been initiated for different clinical application goals, such as diagnosis of pathological posture and movements, assessment of pre- and post-treatment efficacy and comparison of different treatment protocols. Image-based methods for measurements of human posture and movements have been developed, such as the radiography, photogrammetry, optoelectric technique and video analysis. However, it is found that these methods are complicated to set up, time-consuming to operate and could only be applied in laboratory environments. This study introduced a method of using a posture monitoring system in estimating the spinal curvature changes during trunk movements on the sagittal and coronal planes and providing trunk posture monitoring during daily activities. The system consisted of three sensor modules, each with one tri-axial accelerometer and three uni-axial gyroscopes orthogonally aligned, and a digital data acquisition and feedback system. The accuracy of this system was tested with a motion analysis system (Vicon 370) in calibration with experimental setup and in trunk posture measurement with nine human subjects, and the performance of the posture monitoring system during daily activities with two human subjects was reported. The averaged root mean squared differences between the measurements of the system and motion analysis system were found to be 0.999 for dynamic calibration and >0.829 for estimation of spinal curvature change in domain planes of movement during flexion and lateral bending). With the sensing modules located on the upper trunk, mid-trunk and the pelvic levels, the inclination of trunk segment and the change of spinal curvature in trunk movements could be estimated. The posture information of five subjects was recorded at 30 s intervals during daily activity over a period of 3 days and 2 h a day. The preliminary results demonstrated that the subjects could improve their posture when feedback signals were provided. The posture monitoring system could be used for the purpose of posture monitoring during daily activity.
---
paper_title: Real Time Monitoring of Posture to Improve Ergonomics

paper_content:

Back pain is one of humanities most frequent complaints. While dangerous diseases are being combatted on a daily basis, something as simple as bad posture is often overlooked. Bad posture can start off as a simple habit and soon lead to chronic back pain. Thus it is essential to maintain an ideal posture so as to reduce stress on the body. In this paper, monitoring of posture is done using flex sensor placed along the spine to detect the movement or bend. As posture changes from ‘ideal’ to ‘poor’, the user is alerted through a buzzer and LCD. A microcontroller is used to set the limits of ideal posture, which can be user specific. A load cell is used to monitor the variation in body weight and spine stress for poor and ideal postures under sitting and standing cases. The proposed system aims to implement a simple posture monitoring and correction system that can be set up at the work place with ease. This can serve to prevent cases of scoliosis and other spine issues which often start with poor posture.
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paper_title: A novel mobile wireless sensing system for realtime monitoring of posture and spine stress

paper_content:

Poor posture or extra stress on the spine has been shown to lead to a variety of spinal disorders including chronic back pain, and to incur numerous health costs to society. For this reason, workplace ergonomics is rapidly becoming indispensable in all major corporations. Making the individual continuously aware of poor posture may reduce out-of-posture tendencies and encourage healthy spinal habits. We have developed a novel wireless mobile sensing system which monitors spine stress in real-time by detecting poor back posture and strain on the back due to prolonged sitting or standing. The system provides a new method of measuring spine stress at both the back and the feet by integrating posture sensors with strain sensors. Posture and strain data is collected by means of a posture sensor at the neck and weight sensors at the feet. Data is transmitted wirelessly to a central processing station and real-time feedback is provided to the user's mobile device when sustained bad posture is detected. Moreover, the position of the patient (sitting, standing, or walking) can be determined by analysis of the weight sensor data and is visualized in real-time, along with back posture, at the central station by means of a graphical animation. Finally, data from all sensors is stored in a database to enable post processing and data analysis, and a summary report of daily posture and physical activity is sent to the user's email. The use of centralized processing allows for high performance data analysis and storage at the central station which enables tracking of the individual's progress. We demonstrate effectiveness of our system in simultaneously monitoring posture and position by testing in numerous situations.
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paper_title: A wearable embedded device for chronic low back patients to track lumbar spine position

paper_content:

In present scenario, people always work in an enclosed environment where they sit in the bend posture that causes severe damage in lumbar spine. According to the survey of World Health Organization, around the world 500,000 to 800,000 people are suffering from spinal cord injury (SCI). In that about 53% of the people who are aged between 16 and 30 suffer from chronic low back pain. A new wearable device which consists of miniature gyroscope and accelerometer are used in detecting the voluntary action of lumbar spine in the proposed system. The proposed system consists of a vibrator, Bluetooth element, a microcontroller and an android application. The vibrator motor is used to intimate the improper sitting position of the person. A Bluetooth element is used in transmitting the data from the module and the android application that runs on smart phone. It records the analyzed data of the sensor. A microcontroller is used to control the overall working of the designed system. The capability of this cost effective, simple device is capable to measure the lumbar spine position with the efficiency of 95% and provide a feedback to the user.
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Title: A Review on Posture Monitoring Systems

Section 1: INTRODUCTION
Description 1: Introduce the importance of posture monitoring systems, the health issues caused by poor posture, and the elements and types of posture monitoring systems.

Section 2: POSTURE MONITORING SYSTEMS FOR SEATED PERSON
Description 2: Describe the existing sitting posture monitoring systems, classified according to the type of information provided by sensing technologies.

Section 3: Posture monitoring systems based on Weight information
Description 3: Provide details about posture monitoring systems that use weight information, and explain how load or pressure sensors are used to define the spine shape.

Section 4: Posture Monitoring Systems Based on Tilt Angle information
Description 4: Discuss the posture monitoring systems that use tilt angle information, which is derived from inertial sensors, to track spine motion in real-time.

Section 5: Posture monitoring systems based on Spine curvature information
Description 5: Explain the systems that rely on spine curvature information provided by various sensing technologies, including flexible sensors, inductor sensors, and optical fiber sensors.

Section 6: POSTURE MONITORING SYSTEMS COMPARISON
Description 6: Analyze and compare different posture monitoring systems based on the information they use, their effectiveness in detecting various types of sitting postures, and their sensitivity to sensor positions.

Section 7: FUTURE WORK
Description 7: Conclude with prospects for future work, focusing on challenges such as the security of collected information, privacy issues, and the design of portable, easy-to-use systems with real-time reactions and high accuracy.