注塑件机器视觉缺陷检测的几何矫正方法研究

针对多面体注塑零件在机器视觉缺陷检测中的零件图像几何形变问题，提出了基于几何光学原理的矫正算法。在拍摄定位误差不大于1 mm的条件下，所述方法矫正误差理论上<0.1 mm，可满足注塑零件机器视觉缺陷检测的需要。首先对采集的图像进行预处理获取图像边缘；接着将轮廓线交点确定为零件顶点；根据顶点位置分割零件的不同表面并将其映射在二维平面；然后根据几何光学计算图像中每一个像素点的偏移量；最后使用基于几何光学的方法对图像中的像素点进行逐点矫正。利用一组六面体零件模拟实际工况，在不同的拍摄定位误差状态下进行实验，使用Matlab对矫正算法进行验证。实验结果表明，所述方法误差在0.1 mm以内，与理论分析相吻合，满足注塑零件在机器视觉缺陷检测中零件图像几何矫正精度的需要。

Research on geometric correction method for machine vision defect detection of injection molding parts

A correction algorithm based on the principle of geometric optics is proposed to address the geometric deformation of part images in machine vision defect detection of polyhedral injection molded parts. Under the condition that the shooting positioning error is not greater than 1 mm, the correction error of the method is theoretically <0.1 mm, which can meet the needs of machine vision defect detection for injection molded parts. Firstly, preprocess the collected images to obtain image edges; Next, the intersection points of the contour lines are determined as part vertices, and different surfaces of the part are segmented based on their positions and mapped onto a two-dimensional plane; Then, calculate the offset of each pixel in the image based on geometric optics; Finally, perform point by point correction on the pixels in the image. Using a set of hexahedral parts to simulate actual working conditions, experiments were conducted under different shooting positioning error states, and the correction algorithm was validated using Matlab. The experimental results show that the error of the proposed method is within 0.1 mm, which is consistent with theoretical analysis and meets the requirements for geometric correction accuracy of part images in machine vision defect detection of injection molded parts.