Phase-shifting profilometry resistant to varying ambient light

Conventional phase-shifting methods rely on the assumption of constant ambient light (AL), which is often violated in practical applications. To address this issue, what we believe to be a novel phase-shifting method resisting varying AL is proposed. The core idea is to cancel out the time-varying fringe background while preserving the sinusoidal component in the captured fringe images. This is achieved by projecting fringe patterns with specially designed phase shifts and applying difference operations to the captured images. The proposed method effectively suppresses the influence of both polynomial and non-polynomial AL variations, enabling accurate phase retrieval under challenging lighting conditions. Experimental results show that this method reduces phase errors by up to 84.03% compared to state-of-the-art methods under complex AL variations, demonstrating its effectiveness and robustness in practical environments.