Tracking locations of moving hand-held displays using projected light

Lee et al. have recently demonstrated display positioning using optical sensors in conjunction with temporally-coded patterns of projected light. This paper extends that concept in two important directions. First, we enable such sensors to determine their own location without using radio synchronization signals – allowing cheaper sensors and protecting location privacy. Second, we track the optical sensors over time using adaptive patterns, minimizing the extent of distracting temporal codes to small regions, thus enabling the remainder of the illuminated region to serve as a useful display while tracking. Our algorithms have been integrated into a prototype system that projects content onto a small, moving surface to create an inexpensive hand-held display for pervasive computing applications.