An efficient exposure fusion method for 3D measurement with high-reflective objects

Fringe projection profilometry (FPP) has been widely applied in industrial 3D measurement due to its high precision and non-contact advantages. However, FPP may encounter fringe saturation in high-reflective scenes, consequently impacting phase computation and introducing measurement errors. To address this problem, an efficient exposure fusion method is proposed in this paper. We propose incorporating complementary gray codes into the multi-exposure fusion method to improve measurement efficiency for high-reflective scenes. After obtaining high-quality wrapped phase by the fused phase-shifting patterns, complementary Gray code patterns are used to assist phase unwrapping to achieve 3D measurement. This method takes advantage of the fast projection speed and edge error elimination capability of complementary Gray code patterns, requiring only one set of patterns to complete phase unwrapping. Compared to the common multi-frequency method, our method reduces the number of projected images and exposure time. Experiments are conducted to demonstrate the feasibility and efficiency of the proposed method.