High-quality defocusing phase-shifting profilometry on dynamic objects

Defocusing phase-shifting profilometry is now widely utilized in fast 3-D shape measurements for its high efficiency and accuracy. However, motion-induced ripples and phase unwrapping errors can still be observed while the object measured is moving. An efficient motion-compensated defocusing phase-shifting profilometry, which accurately estimates the motion-induced shifts regarding each pixel, both on the image plane and the phase map, to reduce the artifacts occurring in the dynamic scenes, is proposed. The phase error is analyzed by N-step phase-shifting theory, and with the help of optical flow method and five-step phase-shifting method; this error can be processed according to the motion information obtained. The phase unwrapping errors are also fixed with the proposed motion-compensated algorithm. Compared with the traditional phase-shifting profilometry and state-of-the-art methods, our method demonstrates competitive performance on dynamic objects.