Research On The Size Measurement Of Parts Based On Computer Vision

With the development of computer technology and photoelectricity, a new inspection technology based on computer vision has been presented. This technology is a non-contacted method for the dimensional measure using image processing and CCD as the picture sensor , which is now widely applied to the precision measure of the part dimension. In this article, a measure device for the part dimension was designed by means of matrix CCD as sensor and the sub-pixel position of picture of the part dimension was realized. The application of matrix CCD to high precision measure was explored and discussed, which laying the foundation of the precision measure of matrix CCD for complex parts.This device is the alteration of an universal tool microscope in our lab, which consists of a CCD picture sensor, an optical image formation system, a data capture system, a picture capture system, and an optical CCD non-contacted two-dimensional measurement consisting of computer and interrelated mechanical structure. The main content of the thesis is as follows: the theory of picture measurement and the system design; the optical image formation and picture capture system. The measure position precision of part's edge was discussed. The picture sub-pixel edge was detected, which processed the part picture in the computer and obtained high position precision of the picture edge.In the part of theory, several common computational algorithms of the edge measurement were discussed combining with an image preprocess method—Middle filter from two key factors, such as measure speed and measure precision, and circle's Hough transformation are studied and discussed. And the method of the polynomial interpolation for sub-pixel edge measure was also studied elementarily. CCD is very fit for the precision measurement of industry. This technology has large practical value and wide application prospect.