Generation Method of Binary Patterns Based on the Space-Time Combination with Projector Defocusing

This paper proposes a novel generation method of binary patterns based on the space-time combination with projector defocusing technique. The linear superposition theory of the fringe projection profilometry system is described. In terms of the principle and the digital binary defocusing technique, through the accurate sequential control of hardware, a sinusoidal function with wavelength is sampled in "time" and "space" directions to calculate the widths of the projected binary patterns. Then, a series of corresponding square fringe patterns are generated and projected to form a high-quality sinusoidal fringe pattern in the defocused projection volume (i.e., the measured volume). Finally, the performance of our proposed approach is demonstrated by the simulations and experiments, e.g., the phase root-mean-square error of a simulation with three-step phase-shifting method can reach about 0.0286 Rad. The precision level is similar to that of the compared optimization method. Fortunately, our proposed method is more convenient and less time-consuming because the optimization process is avoided.