Transparent Desktop Opens Doors

Leander Kahney Email 07.09.04
The inventors of Facetop got the idea for its novel interface while discussing work in front of a projected desktop while fooling with a Firewire video feed.

Collaborating with co-workers in the same office is painful enough, but it's nigh impossible over a network.

For a couple of decades, researchers have tried to blend shared workspaces -- systems that allow two or more people to work on the same document -- with Internet video-conferencing systems, with little success.

Now researchers at the University of North Carolina at Chapel Hill have designed a new system that cleverly blends a video-conference feed with a transparent image of a computer desktop into one full-screen window.

Called Facetop, the system simultaneously transmits a video feed of users along with a shared, transparent image of the desktop. It allows two colleagues to work on the same document, Web page or graphic, while communicating face to face.

The system also tracks the position of the users' fingertips, which can control a cursor. As well as operating the shared desktop -- opening and closing files or selecting text, for instance -- the collaborators can use natural pointing gestures to communicate ideas about the document.

Developed by David Stotts, an associate professor of computer science, and graduate student Jason Smith, Facetop was conceived for collaborative tasks like programming or editing text. But the researchers say it has obvious uses in other areas such as medical imaging or remote teaching.

"So far, from the feedback we've received, it works fantastically," said Smith. "It's a very natural interaction. You can see the facial expressions and all the nuances of face-to-face communication."

"It's spectacular technology," said Robert Gotwals, associate director of Chapel Hill's Morehead Planetarium and Science Center, who saw a demonstration of an early version. "I've done lots of video-conferencing work. This is pretty cutting edge. It's a fast-moving field and the stuff David (Stotts) is doing is pretty cool."

The system can also be used for delivering lectures or PowerPoint presentations: The speaker is projected in the background of the document allowing her to point out bullet points or important passages. According to Smith, users easily switch attention between the subject and the desktop.

"The brain is really good at picking out what part of the screen the person is interested in," said Smith. "It's like being in a room full of conversations but having no trouble paying attention to only one.… People adapt to the system really naturally."

Facetop may also be used to as an alternative to the mouse, for controlling a machine simply by pointing with a finger.

The system is implemented in Mac OS X and is made possible largely by the system's Quartz rendering engine, which can make any part of the interface transparent. Thanks to Quartz, a quick prototype was whipped up in about 45 minutes, Smith said.

A PC version will likely be delayed until the release of Longhorn, the next major version of Windows, due in 2006, which will include a similar graphics subsystem.

The system is fairly inexpensive; it has been implemented on a pair of Apple PowerBooks and two $100 FireWire cameras. So far it has been tested only on Ethernet networks and not the Internet, though the researchers say there's no reason it shouldn’t work just fine. They are also trying to hook it to Apple's iChat instant-message/video-conferencing software and other similar systems.

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