基于CCD的轴径检测方法

Shaft diameter measuring method based on CCD

给出了一种CCD相机标定与亚像素边缘检测相结合的轴径测量方法。该方法在修改了张正友标定方法中的畸变模型的基础上,利用专门设计的夹具夹持标定板进行CCD相机的外部参数标定,有效地保证了被测轴的夹持状态与标定的外部参数一致。使用拟合形式的亚像素边缘检测算法确定轴的两条边缘的位置,同时给出了利用伪直径确定真实轴径的函数关系式。通过与精密量具的测量结果对比,当轴径的基准尺寸在35～75mm时,该方法测量的平均误差为0.02mm。

A non-contact, high-precision shaft diameter measuring technique was proposed combining the CCD camera calibration and sub-pixel edge detection. Based on the improved distortion model of ZHANG Zheng-you, the parameters of the CCD camera were calibrated fixing the calibration board by a specially designed fixture to ensure the agreement between the clamped state of the measure shaft and the calibrated external parameters. A fitting form of sub-pixel edge detection algorithm was used to localize the two edges in the shaft image. An expression to determine the real shaft diameter from the pseudo-diameter was derived. The comparison of the measuring results with those obtained by the traditional precision measuring tool showed that for the basic dimension of measured shaft diameter 35~75 mm the average error of the proposed technique is about 0.02 mm.