基于图像处理技术的印制电路线宽精密测量与光源光强调节方法研究  

Research on Precise Measurement of Linewidth on Printed Circuit Board Based on Image Processing Technology and Illumination Adjustment Method

作　　者：洪润莉 何佳乐 古庆宏 张真汶 黄杰贤[2] HONG Run-li;HE Jia-le;GU Qing-hong;ZHANG Zhen-wen;HUANG Jie-xian(Guangdong Meizhou Quanlity Metrology Supervisor and Testing Institute,Meizhou 514072,Guangdong;School of Physic and Electronic information engineering,Jiaying University,Meizhou 514015,Guangdong)

机构地区：[1]广东省梅州市质量计量监督检测所,广东梅州514072 [2]嘉应学院物理与电子工程学院,广东梅州514015

出　　处：《电脑与电信》2021年第12期42-46,共5页Computer & Telecommunication

基　　金：广东省市场监督管理局科技项目“AOI(自动光学检测)的校准;检测”,项目编号:2020ZJ03。

摘　　要：为了实现对印制电路板线路线宽的精密测量,以同轴光源为AOI系统的照明装置,采用图像处理技术,提取边缘区域的灰度梯度特征并进行最小二乘曲线拟合,精确定位线路的边缘位置,进而计算得到线路线宽值。在此基础上,分析光照对线宽测量造成的影响,提出基于熵的最佳光照强度调节方法以保证线路线宽的测量精度。通过实验证明,在最佳的光照条件下,该方法可有效地保证测量精度,在成像比例为55.7um/像素条件下,平均误差为13um,约1/4像素。本文提出的方法极具实用价值,对于同类型的、基于图像处理技术的精密测量研究具有参考价值。In order to realize precise measurement for printed circuit board linewidth, Coaxial light is selected as AOI lighting system. Through image processing technology, the gradient feature around boundary region is extracted. And least squares curve fitting is performed on gradient data, the precise position of boundary is located, so the measuring value of linewidth is calculated. Furthermore, for ensuring measuring accuracy, the research also analyzes relation between illuminator and measuring accuracy. And an illumination adjustment method based on entropy is proposed. After the method is implemented to achieve the best illuminator, the measuring result is pleasant, the average measuring error can be reduced to 13 um, about 1/4 pixel on the condition that the image ratio is 55.7 um per pixel. The method is very practical, and provides referent value to precise measuring work based on image processing technology.

关 键 词：印制电路板 线宽 精密测量 同轴光 图像处理 最佳光照 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]