Study On The Measurement System's Machine Vision Modeling Method And Image Processing Algorithms Based On Virtual Instruments

With the development of modern advanced manufacturing technology, it requires the measurement method to be more high-precision, more high-speed. The traditional measurement method couldn't satisfy the special request in the modern manufacturing. So the non-contact measurement method, which based on the machine vision, has become the developmental direction of high-precision measurement technology since the new century.The theories of Virtual Instruments(â…¥) which have been established since 1980s was applied to actual manufacture measurement with the development of the technology of computer and electro, and have tremendous superiorities in the applicability to measurement, the facility to system building and the low cost. These make it valuable and meaning to research on the way of building a machine vision method and image processing algorithms based on â…¥.This paper is based on the military industry cooperative project- Measurement of Positions for Hole Series on Curved Surface, and - Research on Machine Vision and Image Processing technology that is the App foundation item of the Science and Technology Department in Sichuan Province. And it raised the No-contact Measurement system project of â…¥ Spherical Circular Hole Series.The precision measurement of Spherical Circular Hole Series system transformed the three-dimensional measurement on the coordinates of spherical circular hole series to planar measurement by the optical imaging technology, and applied mobile mechanism to drive CCD linear and raster sensor, which captured the images. By the LabVIEW Graphical Development Environment and computer digital image processing technology, this system software identified the center ofcircular hole in the image, and transformed the pixel coordinates to physical coordinates and ultimately reached the demand. The main contexts are as follows:Firstly, the paper introduced the elements and working principle and process of the measurement system, and how to realize the Spherical Circular Hole Series measurement system.Secondly, the paper particularly showed how to build the VI machine vision measurement system based on the Lab VIEW 7.1 and IMAQ Vision 7.1.Thirdly, considering the characteristics of the image capturing hardware, the way of building PC-DAQ VI image capturing module is raised by this paper.Finally, in the image processing and analysis module, the system software identified the hole type(through hole and blind hole) by computing the gray-level histogram; and through median filtering, edge detection, threshold selection, we found the center coordinates of spherical circular hole.After the research, we have built the machine vision measurement system model that based on VI. Only by making a little adjustment to the code diagram, can we measure other types of surface. All these bring the Vis' merit into play, such as facility, and adaptability to task.