A novel defect detection method with eliminating dust for specular surfaces based on structured-light modulation analysis technique

Abstract

In modern industrial manufacturing, the demand for the surface inspection of specular objects has become more and more urgent. In this paper, a novel defect detection method with eliminating dust is systematically proposed to inspect surface defects of specular objects. The proposed approach can be applied to the defect detection of silicon wafers, optical lens, cell phone cover glass, etc. Structured-Light Modulation Analysis Technique (SMAT) is adopted to detect defects and dust simultaneously. Meanwhile, according to the discrepancy of polarization states between dust and other places, polarized illumination and a linear polarizer are exploited to photograph dust image exclusively. The dust image is used to remove dust from the modulation image; thus, the purified defect distribution can be obtained. Relevant experiments are also performed to prove the effectiveness of this proposed approach.