Spatial-Temporal Combined Phase Unwrapping in Phase Measurement Profilometry

A spatial-temporal combined phase unwrapping method is proposed, which improves the noise suppression ability and phase unwrapping reliability of the three-frequency temporal phase unwrapping method. The fringes with sensitivity greater than 1 are used to replace the fringes with sensitivity of 1 in the traditional three-frequency temporal phase unwrapping method. By calculating the wrapped phases of these fringes, the spatial phase unwrapping of them is carried out, and the unwrapped phases are used to guide the unwrapping of the other two high sensitivity wrapped phase images. Compared with the traditional three-frequency temporal phase unwrapping method, the proposed method reduces the frequency multiple difference between the three sets of fringes when the spatial frequencies of the highest sensitivity fringes of them are the same, thus reducing the influence of noise on phase unwrapping and improving the reliability and accuracy of three-frequency temporal phase unwrapping.