多引脚类贴装器件的炉前检测算法

Inspection algorithm of before-furnace for multi-leads surface mounted devices

为了适应多引脚类贴装器件炉前检测的实时性要求,提出了一种针对引脚特征的检测算法。首先分析了多引脚类器件在结构光下的特征;然后设计了一种差分算子,提取引脚的水平和垂直差分,接着对差分值作积分投影,从而避免了设置边缘阈值的困难,在此基础上,利用最大邻域梯度法和滑动滤波窗算法定位引脚位置;最后提取引脚的面积特征并引入模式匹配方法。实验结果表明:本文算法可有效的检测多引脚类器件缺件、错件、偏移、歪斜和翘脚等缺陷,整体准确率为97.7%,检测单个器件的时间约为28ms,能满足在线检测系统高准确率和实时性的要求。

According to the real-time inspection requirements of before-furnace for the multi-leads surface mounted devices, an inspection algorithm based on the lead features was presented. Firstly, the features of the devices under the structure light sources were analyzed. Secondly, the horizontal and vertical differences were extracted with the difference arithmetic operator. Then the differences were projected in order to avoid the difficulty of right thresholding. Based on the integral projections of the differences, the horizontal and vertical borders of the leads were obtained by the maximum neighbor gradient and the sliding filter window algorithm, respectively. Finally, the area features in the leads were ex- tracted and the pattem matching method was applied. The experiment results show that the proposed method can identify the defects such as missing devices, wrong devices, shifts, skews and leads lift effectively, the total success rate was 97.7%, and the time consuming for single device was about 28 ms. Therefore it can satisfy the requests of high accuracy and real-time character for on-line inspection system.