贴片电阻生产过程中的缺陷主要依靠人工在显微镜下检测, 速度慢、长期成本高、误检率高.针对贴片电阻单元具有排列整齐、结构简单、图像灰度级少的特点, 在贴片电阻图像二值化、边缘提取、直线检测基础上, 以相邻电阻单元的相关系数作为电阻缺陷判别依据, 提出基于子图投影匹配的快速缺陷检测方法.采用主分量分析法压缩图像数据量, 提取缺陷特征, 以基于支持向量机对贴片电阻缺陷进行分类并建立实验系统.缺陷检测及识别实验表明, 缺陷检测正确率为92.5%, 算法的快速性和识别准确度满足系统快速高精的要求.

Simple structure, orderliness and few gray level of SMD (surface mounted device) resistor image are the prominent feature of SMD resistor units array, through binary resistor image, edge detection, line detection, with the correlation coefficient as a criterion for defects. A method for resistor flaw detection was proposed based on subgraph projection matching. The feature of resistor flaw was extracted on basis of the method of PCA (principal component analysis). Then the resistor flaw would be classified by SVM (support vector machine). At last, an experimental platform was built and the result verifies that the detection rate employed the proposed method is 92.5%, and the method meets the requirements on high accuracy and speed.