Generalized fringe order correction based on phase shift segmentation for absolute phase retrieval

We present a fringe order correction method for various absolute phase retrieval algorithms. In fringe projection profilometry based on absolute phase retrieval (FPP-APR), the mismatches tend to be easily generated around the 2π discontinuities or edges of the wrapped phase due to the defocus and noise of the system. In this paper, a staggered wrapped phase with a phase shift of 2π / N segments the calculated wrapped phase into a left-wrapped phase and a right-wrapped phase. Then, a statistical method independently determines the fringe order of each closed-wrapped phase without the 2π discontinuities. The experiments demonstrate that the proposed fringe order correction has the generality and simplicity for the existing absolute phase retrieval and performs high robustness to measure the colorfully complex objects of daily life.