An improved two-step phase-shifting profilometry combined with complementary Gray code phase unwrapping

Abstract In order to improve the three-dimensional measurement efficiency by reducing the fringe images in the phase-shifting fringe projection profilometry and obtain high-quality unwrapped phase. An improved two-step phase-shifting profilometry combined with complementary Gray code phase unwrapping is proposed in this paper. The method firstly generates an average intensity image by collecting the redesigned Gray code fringe images, and then eliminates the average intensity in the two phase-shifting fringe images by this image, then the processed phase-shifting fringe images are substituted into the improved two-step phase-shifting profilometry proposed in this paper to effectively adjust the initial phase and get the adjusted wrapped phase. Finally, the wrapped phase is unwrapped by the complementary Gray code phase unwrapping method to get the high-quality unwrapped phase. Experimental results show that only two phase-shifting fringe images could obtain the wrapped phase and the proposed method has strong robustness. Compared with the complementary Gray code ’2+1’ phase-shifting profilometry, the detection efficiency are improved by 14.29%, Compared with the complementary Gray code two-step phase-shifting profilometry (using the phase-shifting profilometry to eliminate average intensity, the detection efficiency are improved by 25%.