面板检测区域位置校正方法研究

Research on Position Correction Method for Panel Detection Regions

面板缺陷检测对真缺陷的检出率和假缺陷的占比有严格的要求。尤其检测区域的定位精度,对缺陷的检出率和假缺陷的占比有较大影响。因为存在检测系统硬件的固有定位偏差,检测区域有漏检或误检的潜在风险。为了提高检测区域的定位精度,增加真缺陷检出率和降低假缺陷占比,通过预先选择面板均匀分布的特征点,设置特征点模板,抓取特征点处图像,将特征点处获取的图像和它的模板图像进行模板匹配。把模板匹配后模板的中心与抓取图像中心位置的偏差作为该特征点处的x方向和y方向坐标偏移量,并用文件保存至硬盘。检测面板时,以检测区域的中心位置为坐标原点,将所有特征点坐标与检测区域中心位置的坐标差按照直角坐标系划分为4个象限,每个象限取两者距离最短的特征点作为有效邻近特征点,按照改进的双线性插值法计算检测区域的偏移量。实际测试表明,该方法能有效校正检测区域的偏差,提高定位精度,定位精度偏差在10μm以内,增加真缺陷检出率和降低假缺陷占比。

Panel defect detection has strict requirements on the detection rate of true defects and the proportion of false defects.In particular,the positioning accuracy of the detection area has a great impact on the detection rate of defects and the proportion of false defects.Because of the inherent positioning deviation of the detection system hardware,there is a potential risk of missing or misdetection in the detection area.In order to improve the positioning accuracy of the detection area,increase the detection rate of true defects and reduce the proportion of false defects,the feature points uniformly distributed in the panel are preselected,the feature point template is set,the feature point image is grabbed,and the image acquired at the feature point is matched with its template image.Taking the deviation between the center of the template and the center of the grasp image after matching the template as the x-direction and y-direction coordinate offset at the feature point,and the file is saved to the hard disk.In the panel detection,all the coordinates of the detection area are the coordinate origin,and the coordinates of the detection area are divided into four quadrants according to the rectangular coordinate system.Each quadrant takes the feature point of the shortest distance as the effective adjacent feature point,and the offset of the detection area is calculated according to the improved bilinear interpolation method.The actual test shows that the method can effectively correct the deviation of the detection area,improve the positioning accuracy,with the deviation within 10μm,increase the detection rate of true defects and reduce the proportion of false defects.