An improved phase measuring deflectometry method for defect detection of specular reflection surface

For specular reflection surface detection, high reflectivity is a large challenge to effectively extract the depth information of surface. Phase Measuring Deflectometry (PMD) based three-dimensional shape measurement is proposed for solving this problem. In this study, PMD method based on the characteristic of high specular reflectivity is used to perform structured light imaging on the glass surface to obtain depth information on the surface of the glass panel. In this paper, we propose a new image reconstruction method suitable for imaging specular reflection surface defects. According to the characteristic of the glass panel, the proposed method has a phase pre-unwrapping process and improves the least square method of unfolding and folding the phase algorithm. The experimental results show that the proposed method is more robust for imaging and detection of high-reflective plane than the traditional least squares method.