An adaptive fringe projection method for 3D measurement with high-reflective surfaces

Fringe projection profilometry (FPP) has the advantages of non-contact, quick and high accuracy, which is popular in the fields of industrial inspection and measurement. However, the coded fringe patterns may be failure suffered from the high reflectivity of the measured surfaces. Aiming at this problem, an adaptive fringe projection method is proposed in this paper by the best projection intensity strategy and the coordinate mapping establishment between camera and projection regions. Combining the local camera response function, the dichotomizing search is used to confirm the best projection intensity of overexposed regions by pixel-wise. The unwrapping phase map of background is performed to establish the coordinate mapping relationship of measured overexposed regions between the camera and projection images, which is robust and convenient. The mapping errors caused by inaccurate phase information in the overexposed regions are effectively avoided, and the fringe projection patterns are adjusted adaptively, without additional equipment and low-expose patterns. Both theory and experiments have verified the feasibility and superiority of the proposed method.