High-speed active head tracking system

We report on the development of a highly scalable head-tracking system capable of tracking many users. Throughout the operating area, a series of high-speed (4 kHz) near-infrared LED-based Digital Light Processor (DLP) picoprojectors provide overlapping illumination of the volume. Each projector outputs a sequence of binary images which encode the position of each pixel within the projected image as well as an identifier sequence for the projector. Overlapping projectors use differing temporal multiplexing to allow sensor discrimination and background rejection. Pixel positions from multiple projectors received by each sensor are triangulated to obtain position and orientation.