强反射复杂表面随机缺陷检测照明系统分析

Illumination System for Detecting Random Defects on Strongly Reflective and Complex Surfaces

分析了采用CCD光电检测法对强反射复杂表面随机缺陷进行检测时的光学照明问题。给出了缺陷显现力的具体定义。对比了平行光和均匀散射光对消除强反射光的不同作用及对不同表面缺陷的显现力。分析了使用均匀散射光作为光源时 ,工件表面照度对成像质量的影响。给出了在上述条件下光照系统设计的基本原则。

The illumination methods related closely to detect random defects on strongly reflective and complex surfaces with CCD detection are discussed. A concept of defect expressivity is developed and the dependency of image quality on luminance is illustrated in the condition of scattered light. Based on the comparisons between parallel light and uniform scattered light, it is concludes that uniform scattered light is much better than parallel light in reducing the mirror reflection and good at revealing the various surface defects. The design principles under those particular conditions are presented.