小孔孔径及同轴度精密影像测量算法的研究

Research of the Algorithm of Precision Image Measurement Algorithm of Small Hole Diameter and Coaxial Degree

针对小孔加工后采集得到噪声图像的特点,提出对提取的亚像素轮廓进行多次寻心处理及最小二乘圆拟合,以获得拟合圆的圆心坐标和直径长度的方法。通过对零件内外轮廓最小二乘圆拟合而得的圆心坐标进行数学计算,从而得出零件内外孔同轴度。该方法相比于传统接触式检验和一般非接触式检测方式,不但测量精度高,而且费时少。通过对标定板和光面环规标准件的测试结果表明,基于机器视觉的小孔孔径及同轴度测量算法,可使得小孔孔径及同轴度重复测量精度小于0.5μm。该测量方法已用于到水处理喷丝头等零件的测量。

According to the machining characteristics obtained after the noise image, put forward several heartseeker processing and least square circle fitting of sub-pixel contour extractionmethod to obtain the center coordinates and the diameter length.Through mathematical calculation of center coordinates and parts contour of least square circle fitting, it could get parts coaxial degree. Compared with the traditional contact measurement method and the general non-contact measurement method, this method not only has high accuracy, but also consumes less time. The test results of the calibration plate and smooth ring gauge standard parts show that the hole diameter and the coaxial measurement method based on machine vision can make the small hole diameter and coaxial degree of repeated measurements accuracy is less than 0.5μm. The measuring method has been used to measure the processing of the water treatment of the first part of the spray wire.