Researchers from Aachen University's Media Computing Group have created a computer workstation where the desk and screen are transformed into one multi-touch display. The display is curved at the middle and uses infrared emitters and cameras to track user movement over the whole of the surface, which has its graphical user interface beamed onto it by a couple of short throw projectors hidden within its wooden frame.

Those who spend much of their working lives at a computer workstation will be familiar with the usual setup of one or two (or more) vertical displays set somewhere towards the back and input peripherals laid out on a horizontal area at the front. Users generally place a number of other objects on the flat surface in front of them too, such as paper documents (despite numerous moves towards a paperless office), pens and mugs of coffee.

There are of course, specialist desks that tilt at an angle or are split over various levels to accommodate the kind of work being undertaken on them, but the designers of BendDesk wanted to create a standard workstation environment that "supports interaction with digital documents but also respects the nature of traditional desks."

BendDesk's monitor area to the front is joined to the desk area by a curve which allows for seamless integration between all areas of the display, with the user interface presented over the whole of the multi-touch surface.

Putting it all together

Inspired by Sun's Starfire video prototype from the mid-1990s, BendDesk is made up of a 104 x 104 cm (40.9 x 40.9-inch) acrylic surface that is curved in the middle to provide the horizontal and the vertical display areas. There's a non-acrylic strip to the front of the board which, in addition to fixing the acrylic, gives the user somewhere to rest the hands. The acrylic board is surrounded by 312 LEDs that feed infrared light into the surface.

Surface touches are detected by Frustrated Total Internal Reflection, where three Point Grey FireFly MV cameras with IR filters – each running at 60 frames per second at a resolution of 640 x 480 pixels – track the entire surface, and special algorithms translate the results into onscreen touch points.

The user interface is beamed onto the rear of the acrylic board at 1024 x 768 resolution by an Optoma EX525ST projector for the vertical display board, and by an NEC WT615 projector for the curve and the horizontal desktop. The latter is positioned so that the user can sit quite close to the desk without risk of interference. In order to compensate for any distortion of the user interface, the system runs through an off-screen buffer.

All of the component parts are mounted in a half-closed wooden box. The setup was designed so that users could sit comfortably at BendDesk and have all input surfaces within easy reach.

Performance evaluation

BendDesk's performance was evaluated using 18 volunteers who were asked to complete a series of dragging and aiming tests. The researchers found that rather than thinking of the display as one big interactive surface, users tended to separate the vertical and horizontal planes and avoid using the curve as much as possible. This could have been due to the fact that dragging virtual objects over the curve was significantly slower than on the flat and aiming at targets on the screen was impaired, but may also be due to what we're used to.

For obvious reasons, most of us work at a flat desk somewhat differently than we do on a vertical display – we use a mouse cursor to draw objects on a screen and a pen when using real documents, for instance. Although BendDesk breaks down such boundaries, users seemed to prefer to treat the horizontal and vertical areas as separate entities. Any future application development could take advantage of this, and use the curved area as a temporary object storage area between the two larger display areas, or as a kind of system dock.

Researchers also noted that extended full range use of the system resulted in some of the volunteers suffering from muscle fatigue, although most users found dragging action could be undertaken for long periods without any adverse effects.

Future development

With further development, the BendDesk prototype does hold a lot of promise for image and document manipulation for professionals, as well as potential for education and home use.

Video editors could store the various scenes of a movie on the lower surface, assemble them into order on the curve and then move them up to a vertically-displayed timeline. A similar technique could be employed for moving, rotating, and scaling objects in presentations or putting together photo albums. Being able to place paper-based books, newspapers and magazines onto such a surface could yield numerous benefits for researchers and copywriters. As for multi-touch, gesture-based gaming – the possibilities are mind-boggling.

The Media Computing Group at RWTH Aachen University in western Germany plans to continue the development of BendDesk and will be looking to experiment with different curve radii and application creation, as well as investigating the practical real-world uses for such a system.

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