一种PCB表观检查机的无阴影高均匀照明方法  

A shadow-free and uniform illumination method for automatic visual inspection of printed circuit boards

作　　者：谢煜[1] 叶玉堂[1] 张静[1] 刘莉[1] 刘霖[1] 

机构地区：[1]电子科技大学光电信息学院,四川成都610054

出　　处：《光电子．激光》2012年第7期1279-1284,共6页Journal of Optoelectronics·Laser

基　　金：粤-港关键领域重点突破(20091683)资助项目

摘　　要：印刷电路板(PCB)表观检查机的检测算法,对亮度不均的阴影条纹的原始图像难以处理,最终影响PCB的检测性能。本文基于实验图像阴影条纹的形成机理,提出一种无阴影高均匀的PCB表观检查机照明方法。本方法采用4个荧光灯组成,其中两个光源与物面的镜面方向对称,用于高反射照明;另外两个光源用于漫反射照明。仿真和实验表明,本方法可以消除高反射曲面引起的图像阴影条纹,在PCB表观检查机系统中达到均匀照明效果且增强缺陷和背景的对比度。本方法也可应用于类似的高反射曲面的自动表观检查系统,如铝带缺陷检查,塑料薄膜缺陷检查等。Unevenly distributed color image and image shadow of the pads on printed circuit board （PCB） are problems in an automatic visual inspection system. This makes it difficult for material classification and local threshold determination. In this paper, an illumination method with high uniformity by using four fluorescent lamps is proposed to eliminate the image shadow for the inspection of printed circuit board. The simulation and experimental results indicate that the method is appropriate in removing the image shadow of PCB image. Furthermore,this method can enhance the image contrast, so defects are also detectable. This method can be also applicable in other specular non-planar surface inspection systems.

关 键 词：印刷电路板(PCB) 图像阴影 照明设计 自动表观检查 均匀照明 

分 类 号：TP216[自动化与计算机技术—检测技术与自动化装置]