Creating a Touch-Screen on a Countertop

By translating shapes into computerized images, this system can turn any surface into a touch-screen.

Graduate students use hand gestures and motions on a simple tabletop to input various commands into the computer at Purdue’s C-Design lab. Infrared depth sensors (in the white bar on the table's far side) measure the position of hands and fingers in 3-D space. An image-processing algorithm tracks and interprets hand gestures and motions over time.C-Design Lab/Purdue University

The next step in touch-screens may be to ditch the actual screen, according to researchers at Purdue University. Engineers Karthik Ramani and Niklas Elmqvist and their colleagues recently unveiled a projector-based computer input system that can transform desks, office walls, or even kitchen islands into interactive surfaces.

The system, called extended multitouch, consists of a computer, a projector, and a Microsoft Kinect depth-sensing camera. (Also used for the Xbox 360, Kinect enables users to interact with games and devices optically, without touching anything.) The projector displays the contents of a typical computer screen onto a surface like your refrigerator or stone countertop, while the Kinect’s infrared laser and receiver estimate the distance to the surface.

Any surface transforms into a touch-screen with the extended multitouch system. It can decipher several hands, (left) translating their shapes into computerized images (center) and maps of each hand's touchpoints (right). | C-Design Lab/Purdue University

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