A Novel Microdefect Imaging System for High-Reflective Material Surfaces

Highly reflective materials, owing to their reflective characteristics, pose challenges in imaging microdefects under conventional lighting, resulting in a substantial number of missed detections. This article presents an imaging method tailored for microdefects on the surfaces of such materials. An investigation into the imaging mechanisms of microdefects under varying illumination conditions is conducted, leading to the proposal of an edge-light scanning technique. Initially, this technique enhances the contrast of defect imaging optically, yielding a sequence of images with high-contrast defects. Subsequently, a contrast-weighted image synthesis algorithm is introduced to effectively mitigate the interference caused by bright and dark stripe backgrounds. Experimental evaluations of defect detection based on different algorithms demonstrate that the proposed imaging method is applicable to defects of various sizes and significantly improves the detection accuracy of microdefects.