The Key Technology And Implementation Of Projector-Camera Based System

Augmented Reality (AR) allows the user to see the real world, with virtual objects superimposed upon or composited with the real world. Therefore, AR enhances a user's perception of and interaction with the real world. Now it has become an important research field in Virtual Reality and next generation of human computer interface.In this paper, we developed a fast and reliable yet cheap AR system, based on camera and projector, which allows the user to interact with the information projected on the floor. Markerless optical motion tracking is a challenging task, especially applied for interactive environment where real-time is required. Tracking method based on figure-ground extraction seems to have the ability for robust real-time tracking. But traditional background subtraction methods are unable to adapt their background model to the fast changing unpredictable images shown on a projection screen. This paper describes an approach to solve this challenging problem. The presented method uses a digital screenshot of the projection screen content to build an intermediate background model fitting a conventional background subtraction algorithm.The building process of background model is composed of geometric and color transformation. The screenshot is first transformed geometrically to match the projection screen. The result is processed by a color transformation to adapt to the color appearance of screen. Then the actual segmentation takes place. And finally the position feature is extracted.The system requires no special hardware, and sufficiently accurate algorithms for segmentation are used, which allows a wide application of the system in the near future.