Eliminating the effective phase ambiguity with as few fringe patterns as possible is a huge challenge for fringe projection profilometry (FPP). The stereo phase unwrapping (SPU) technologies based on geometric constraints can achieve phase unwrapping without projecting any additional patterns, which maximizes the efficiency of the absolute phase retrieval. However, when high-frequency fringes are used, the phase ambiguities will increase which makes SPU unreliable. The adaptive depth constraint (ADC) method can increase the robustness of SPU, but it is difficult to deal with scenarios without the priori depth guidance. In this work, we propose a stereo phase unwrapping method based on feedback projection to robustly unwrap the wrapped phase of dense fringe images. Aiming at the problem that the ADC is too dependent on the last measurement result, a simple and effective deep anomaly detection strategy is proposed. After determining the reconstruction error, through the proposed fully automatic projection feedback mechanism, the absolute depth of the object can be quickly obtained to correct the dynamic depth range of the ADC, thus guiding the acquisition of high-quality 3D information. Experiments prove that this approach can achieve high-speed, real-time, and high-resolution 3D measurement with a measurement speed of 30 Hz under the premise of using two perspectives.
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