第6期 2016年6月
组合机床与自动化加工技术
ModularMachineTool&AutomaticManufacturingTechnique
文章编号：10012265(2016)06003005
DOI;10. 13462/j. cnki, mmtamt. 2016. 06. 008
PCB基准点的探针式鲁棒定位方法
曾友高健岑誉
No.6 Jun.2016
（广东工业大学机电工程学院机械装备制造与控制技术教育部重点实验室，广州510006）
摘要：为了提高印刷电路板(PCB)基准点的定位鲁棒性与定位精度，减少因基准点损坏而定位不准或者不能定位现象，提出了探针式基准点定位方法。该方法分粗定位与精定位两步，粗定位阶段首先采用区域增长法进行图像分割，通过圆度阔值筛选出圆形区域，运用所提出的探针定位方法建立探针法数学模型，实现基准点的粗定位。基于粗定位所得基准点区域图像，提取其图像亚像素边缘，提出基于稳健估计算法的几何距离法圆拟合方法，实现基准点的精定位。实验结果表明：在复杂背景下该探针式定位法的基准点识别结果的正确率达100%，可有效降低基准点误定率；定位方法对基
准点污损不敏感，在基准点损坏50%的情况下定位精度还能达到0.021个像素。关键词：PCB基准点；计算机视党定位；探针法；边缘检测；几何法圆拟合
中图分类号：TH16；TG506
文献标识码：A
RobustProbeTypePositioningMethodforthePCBMarkPoint
ZENGYou,GAO Jian,CENYu
(School of Electromechanical Engineering, Key Laboratory of Mechanical Equipment Manufacturing & Control Technology of Ministry of Education, Guangdong University of Technology, Guangzhou 510006, China)
Abstract: In order to improve the robustness of localization and positioning accuracy of PCB(Printed circuit board)，reducethephenomenon of wrong location or unable location forthedamaged mark point,a probe method is proposed. The method is divided into the coarse positioning and the accurate positioning, About the coarse stage: First, using the region growing algorithm to segment the image. Then choose the circular re gion with roundness threshold. At last the probe detection method is proposed and a mathematical model is set up to complete the coarse positioning. At the accurate positioning stage,the sub-pixel edge of the image should be obtain first. Then using the geometry method and combining the robust estimation method,the cir-cle of the mark point is fitted,so the accurate positioning is completed. The experimental results show that the probe method is effective,its right positioning rate is as high as 100% under the complicated background. This means that the wrong positioning rate is highly decreased. The results also shows that the circle fitting method is not sensitive with the damage and stains. The positioning accuracy can reach 0. 021 pixel even though the mark point is damaged 50% . Its effect is far superior to the other method described in this paper. The requirements of mark point positioning of stable,reliable,high accuracy and low sensitivity of damage and stains are reached
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引言 0
基准点是PCB板上的定位标识，常见形状有圆形、菱形、三角形和十字形等，其中以圆形居多"]。在表面贴装技术中，PCB板上各元件位置都以基准点为基准，因此怎样快速准确的找到基准点位置成为表贴
装工艺中一个极其关键环节。这一任务由贴片机机器视觉系统实现。定位的精确度、稳定性以及定位速度等是衡量视觉定位系统好坏的性能指标。对于圆形基准点，传统定位方式主要有：Hough变换、曲线拟合、边缘检测以及模板匹配等(3)。这些方法各有其特点，如
收稿日期：20150527
+基金项目：国家重点基础研究发展计划项目(973计划)(2011CB013104)；广东省高等学校科技创新重点项目(2012CXZD0020）；广东省战略性新
兴产业专项资金（2012A080303004,2011A081301001)
作者简介：曹友（1990—），男，期南邵阳人，广东工业大学硕士研究生，研究方向为图像处理，（E-mail)1123838773@q9-com；高健（1964—），女，
山东青岛人，广东工业大学教授，博士生导师，研究方向为在线检测和机器视觉技术。
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