受基板颜色干扰的SOT-23贴片元件定位方法的改进  

Improvement of the Location Method for SOT-23 Patch Element Interfered by Substrate Colors

作　　者：吴卫东 罗兵 廖红俊 WU Wei-dong;LUO Bing;LIAO Hong-jun(Faculty of Intelligent Manufacturing,Wuyi University,Jiangmen 529020,China;Shenzhou Vision Technology Co Ltd,Dongguan 523127,China)

机构地区：[1]五邑大学智能制造学部,广东江门529020 [2]东莞市神州视觉科技有限公司,广东东莞523127

出　　处：《五邑大学学报（自然科学版）》2023年第3期51-56,72,共7页Journal of Wuyi University(Natural Science Edition)

基　　金：江门市科技计划项目(2020030103000008537).

摘　　要：在黑色PCB基板上,SOT-23元器件的本体与其颜色相近,传统的基于边缘查找、图像分割的引脚质心法存在定位精度低、易受基板丝印线和相邻元件干扰等问题.为解决这些问题,本文结合贴片安装元件引脚和焊点的关系对引脚质心法进行改进.首先提取焊点轮廓,然后根据焊点与元器件引脚、本体的几何关系定位元器件的偏转角,由引脚位置拟合求元器件的质心,定位元器件的XY位置.实验结果表明:本文提出的改进算法与引脚质心法相比,元器件偏转角的平均定位精度提高0.48°,元器件中心位置的平均定位精度提高2.38个像素.改进方法可以用于SOT-23元器件的定位检测,具有一定的工程应用价值.On black PCB substrates,the body of SOT-23 components is similar to their color.The traditional pin centroid method based on edge search and image segmentation has the problems of low positioning accuracy,being prone to interference from substrate screen printing lines and adjacent components.In this study,the pin centroid method was improved based on the relationship between the pin and the solder joint of patch mounting elements.Firstly,the solder joint contour was extracted,and then the deflection angle of the components was located based on the geometric relationship between the solder joint,the component pins and the body.The centroid of the components was calculated by fitting the pin position to locate the XY position of the components.The experimental results show that compared with the pin centroid method,the improved algorithm proposed in this article has an average positioning accuracy improvement of 0.48°for component deflection angle and 2.38 pixels for component center position.The improved method can be used to detect welding defect of SOT-23 components,and has certain engineering application value.

关 键 词：PCB基板 图像分割 引脚质心法 偏转角定位 缺陷检测 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] TN41[自动化与计算机技术—计算机科学与技术]