PlayAnywhere – Microsoft's Interactive Playground

Microsoft recently introduced “PlayAnywhere” – a front-projected computer vision-based interactive table system, which the company says demonstrates the latest improvements in projection technology. PlayAnywhere was designed using advanced image processing techniques and Microsoft says this compact product addresses installation, calibration, and portability issues that are typical in most vision-based table systems. PlayAnywhere’s creators said they aimed to create a system capable of sensing a variety of objects and of displaying animated graphics over large display surfaces.
Unlike many similar systems, PlayAnywhere’s projector and camera are placed on the side of the tabletop, and the device can sense and project images on a 40'' diagonal area at a relatively short distance. Andrew Wilson, one of the researchers who worked on the project, said the system demonstrates a number of important sensing capabilities that exploit the flexibility of computer vision techniques. These sensing capabilities include a novel touch detection algorithm based on the observation of shadows, and an optical flow-based algorithm for the manipulation of onscreen objects that does not rely on fragile tracking algorithms.
PlayAnywhere consists of three primary components: a projector, cameras, and an infrared illuminant – constructed as a single piece. The projector stands on a short pedestal, which is placed directly on the targeted surface, and uses four aspheric mirrors to project a visibly correct rectangular image from oblique angles at short distances. Multiple cameras and the infrared illuminant are mounted on the projector itself, in order to preserve the calibration of the vision system with the display, regardless of where PlayAnywhere is situated.

Reference: http://thefutureofthings.com/news/1037/playanywhere-microsofts-interactive-playground.html