基于最小外接梯形的透视畸变圆心位置校正

Minimum external trapezoidal correction of perspective distortion circle center position based on machine vision

针对机器视觉检测中出现的圆形透视畸变导致圆心出现偏差的现象,提出一种基于最小外接梯形校正方法。以畸变圆最小外接梯形对角线交点坐标确定畸变圆圆心位置。以选定零件内孔尺寸为试验对象,研究比较了利用霍夫变换法、最小外接矩形法及最小外接梯形法确定圆心位置坐标的不同。结果表明,运用最小外接梯形确定相比最小外接矩形确定与霍夫变换确定圆心坐标的相对误差有明显降低,并且利用最小外接梯形的校正误差稳定在1%~2%,有着更高的精确度和稳定性,为圆心位置的检测以及圆形透视畸变的校正提供了有效的方法。

Aiming at the phenomenon that the circular perspective distortion in machine vision inspection leads to the deviation of the center of the circle,a minimum external trapezoidal correction method is proposed in machine vision.The position of the distortion circle is determined by the coordinates of the smallest external trapezoidal diagonal intersection.The coordinates of the inner hole positions with the Hough transformation method and the minimum outer rectangular method were compared.The experimental results show that the use of the minimum external trapezoid than the minimum external rectangle and hoff transform determine the relative error is significantly reduced,and the correction error using the minimum external trapezoid is stable at 1%-2%,which has higher accuracy and stability,the detection of the center position and circular perspective distortion correction provides an effective method.