为了有效地检测印刷电路板(PCB)圆孔光电图像同心圆的圆心与边缘,在Hough变换的基础上提出了一种新的同心圆检测方法。利用同心圆的几何特点对点Hough变换边缘点的点组选取方法和搜索点组的图像扫描方向进行了改进:首先由累加阵列确定同心圆的圆心,然后由圆心到各个有效边缘点距离的均值求出半径,从而检测出同心圆的圆心与边缘。对实际采集的PCB定位圆孔光电图像进行对比实验,在提高检测精度、降低内存空间、减少计算时间方面,该检测方法的优势明显。

In order to detect the center and radius of concentric circles of photoelectric image of circular hole effectively in printed circuit board (PCB),a novel method for the detection of concentric circles based on Hough transform was proposed. The method for the point sets selection of point Hough transform and the scan direction for image of searching the point sets were improved by using the geometrical characteristic of the concentric circles:The center of the concentric circles was obtained in the accumulative array firstly,radius was obtained by the mean of distance between the circle center and every edge points afterwards,both the circle center and the edge of the concentric circles were detected accordingly. After the contradistinctive experiments for the detection of photoelectric image of PCB positioning circlular hole obtained in reality,the detection method proposed in this paper has obvious advantage in the aspects of increasing detection precision,reducing memory space and time.