Absolute phase correction for phase-measuring profilometry based on color-coded fringes

A phase correction method that utilizes fringe color-coding in phase-measuring profilometry is proposed. Original and additional fringes are encoded into the R and B channels, respectively. The R + B channel patterns are projected onto an object, captured using a camera, where the R and B channels are extracted. Then, phase shifts obtained from the R and B channels are utilized for absolute phase calculation and correction. Simulations and experiments demonstrate that this method can correct edge order errors and avoid increasing the fringe number. Experiments performed using the R + G, G + B, and R + B channels demonstrate that R + B exhibits the least color crosstalk. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)