Absolute Phase Retrieval Using Phase-Coding Patterns and Universal Complementary Strategy for 3D Profilometry

In three-dimensional (3D) shape measurement, codewords decoded from phase-coding patterns and wrapped phase extracted from sinusoidal patterns cannot maintain strict consistency at the edge of fringe period due to some unexpected influencing factors, such as defocus, noise and limited depth of field, resulting in occurrence of jump errors in absolute phase. To this end, a universal complementary strategy with high-frequency phase-coding patterns is proposed to avoid the jump errors for fringe projection profilometry (FPP). By splitting staggered fringe order sets from phase-coding patterns and dividing wrapped phase into different segment, the resulting fringe order can align with wrapped phase which guarantees the success of phase unwrapping. Furthermore, an improved method combining low-frequency phase-coding patterns with only one gray-coded fringe pattern is also used to elevate the accuracy rate of phase unwrapping. Simulation and experiments have shown that the proposed methods can greatly mitigate the phase jump errors, which implements in a simple and efficient way for 3D measurement of complex scenes.