An improved quaternary complementary Gray code phase unwrapping method in fringe projection profilometry

This paper presents a phase unwrapping method utilizing an improved quaternary complementary Gray code in fringe projection profilometry. Traditional methods often require a high number of additional projection patterns, which are aimed to be minimized. The proposed approach decomposes the last quaternary Gray code pattern into two binary Gray codes, integrating a complementary strategy for error prevention. This method enhances the accuracy of order calculation while retaining the efficiency of the quaternary Gray code. To obtain the codewords corresponding to the four grayscale levels more conveniently and accurately, a point-to-point threshold segmentation strategy is introduced to enhance segmentation. Additionally, an isolated order correction strategy is proposed to mitigate noise-induced errors. Experimental results validate the feasibility and superiority of the method over conventional techniques, demonstrating its improved efficiency and robustness.