A phase unwrapping method based on sparse depth for depth perception

The phase ambiguity is the main difficulty in the phase unwrapping of three-step phase-shifting. In this paper, a novel three-step phase-shifting phase unwrapping method based on sparse depth map is proposed. The sparse depth map is an auxiliary in phase unwrapping for depth acquisition. Firstly, a novel random grid pattern is proposed based on the random speckle and Delaunay triangulation in this algorithm. Secondly, the sparse depth can be calculated based on the proposed random grid. Finally, the phase unwrapping sequence is designed based on proposed quality of relative phase map (quality map). The calculated sparse depth is used as an auxiliary to solve the absolute phase according to designed phase unwrapping sequence. The depth can be acquired based on proposed phase unwrapping algorithm. In the experiment, the reliability of the proposed phase unwrapping algorithm has been verified in simple and complex scenes respectively. The phase ambiguity can be avoided by this method. Experiments show that this method has advantages in both accuracy and resolution.