“网格式平行线法”在螺纹参数测量中的应用

在计算机视觉理论基础上发展起来的视觉检测(vision inspection)技术具有非接触、速度快、精度适中、可实现在线等优点，已广泛地应用于工业产品的在线检测。在计算机视觉检测技术中CCD摄像机是一个最关键的器件，其参数是否准确决定了检测的精度。所以，摄像机标定是视觉检测技术中最基本的也是最重要的一步。在比较其他标定方法的基础上，为了解决传统标定方法对螺纹图像测量系统所带来的一系列问题，采用了一种新的图像测量系统的标定方法——网格式平行线标定方法，该方法运用了CCD亚像素细分技术及调焦技术，可直接得到纵横2个方向的像素，经过理论分析及实验结果均表明，采用该方法具有标定简单、精度高、重复性好等优点，是一种较好的螺纹图像测量系统标定方法。

Application of the gridded-parallel-line calibrating method in tubing thread metrology

The visual inspection technique based on the automated vision has many advantages,such as non-contact,high speed,accurate and online etc. It is widely used in the on-line examination of the industrial product. CCD camera is the key part in the Automated Visual Inspection. The accuracy of the examination is based on the CCD's parameter. So the calibration of CCD is critical for the process. In order to resolve the problems caused by traditional calibration methods,a new method is introduced to calibrate the tubing thread measurement system. The new gridded-parallel line calibration method adopts CCD subpixel technique.Theoretical analysis and experimental results show this method has the advantages of high accuracy,easy operation and good repeatability.