ACM TechNews

Hands-On Computing

Scientific American (07/08) Vol. 299, No. 1, P. 64; Brown, Stuart F.

Multi-touch computer screens could make a mouse or keyboard unnecessary for enhanced collaboration by being able to follow the instructions of many fingers at the same time. Perceptive Pixel has developed a wall-size screen that is responsive to as many as 10 fingers or multiple hands, and early adopters of the technology include intelligence agencies that require fast comparison between geographically coordinated surveillance images in their war rooms. Among the challenges of refining multi-touch screen technology are sensing the precise location of fingers, and developing software routines capable of tracking the finger movements and converting them to instructions for what should be happening with on-screen images. Perceptive Pixel founder Jeff Han devised a multi-touch screen that produces 10 or more streams of x and y coordinates simultaneously, and he points out that "the traditional [graphical user interfaces] are really not designed for that much simultaneity." Perceptive Pixel's design involves projectors that transmit images through an acrylic screen onto the surface facing the viewer, and when fingers, styli, or other objects make contact with the surface, infrared light shone inside the acrylic sheet by light-emitting diodes (LEDs) scatters off the objects and back to sensors; the data is interpreted as movements by software. Microsoft, meanwhile, has created a multi-touch table called Surface that projects imagery up through the acrylic top. In addition, an LED light source shines near-infrared light that reflects off fingers or objects back to various infrared cameras, while a computer tracks finger movements by monitoring the reflections.

http://www.sciam.com/article.cfm?id=hands-on-computing

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