Selection of temporally dithered codes for increasing virtual depth of field in structured light systems

Temporally dithered codes have recently been used for depth reconstruction of fast dynamic scenes using off-the-shelf DLP Projectors. Even though temporally dithered codes overcome the DLP projector´s limited frame rate, limitations with the optics create challenges for using these codes in an actual structured light system. Specifically, to maximize the amount of light leaving the projector, projector lenses are designed to have large apertures resulting in projected patterns that appear in focus over a narrow depth of field. In this paper, we propose a method to design temporally dithered codes in order to extend the virtual depth of field of a structured light system. By simulating the PWM sequences of a DLP projector and the blurring process from the projector lens, we develop algorithms for designing and decoding projection patterns in the presence of out of focus blur. Our simulation results show a 47% improvement in the depth of field when compared against randomly selected codewords.