通过分析由三色LED环形结构光源和3-CCD彩色相机获取的印刷电路板(PCB)焊点图像特征,设计了一种PCB无铅焊点假焊的检测方法,以提高自动光学检测系统检测焊点质量的准确率,降低误判.该方法通过对焊点及其元器件的定位,采用重心法检测假焊;根据焊点及元器件的边缘确定焊点区域及元器件区域,采用面积法二次检测假焊;最后,采用提出的色彩梯度法,检测剩余的假焊焊点.基于以上三步骤,实现对整张PCB焊点假焊的检测.实验结果表明,采用重心法、面积法及色彩梯度法相结合的方法,可检测出PCB焊点的假焊,检测准确率为99.2%.%In order to improve the inspection accuracy and reduce misjudgment rate for the solder joint quality inspection in an automatic optical inspection system, a pseudo solder joint inspection method for lead-free solder joints in a Printed Circuit Board(PCB) was proposed based on analyzing the solder joint image acquired by a 3-color LED structure illuminator and a color 3-CCD camera. Three steps were used to detect the pseudo solder joints. Pseudo solder joints were inspected firstly by the center of gravity method after positioning the solder joints and its components. Then, the regions of solder joints and components were figured out based on their edge, and the area method was used to inspect pseudo solder joints. Finally, the missed pseudo solder joints were inspected by the proposed color grad method. The experiment results show that the proposed method composed of the center of gravity method, area method and the color grad method can inspect the pseudo solders effectively, and the inspection accuracy can reach 99.2 ％.
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