Study On Automatic Measuring Technology Of Universal Tool Maker's Microscope Based On Machine Vision

To survey geometric dimension of the object precisely is applied widespread and valuable in the detection technology. Regarded as the traditional 2-D coordinate measuring system, universal tool maker's microscope is widely used in the optical metrological instruments for the sake of performance stabilization, high measurement accuracy and convenient operation. But the inherent weakness of the traditional optical metrological instruments is one restriction for the use in some cases, such as uneasy aiming, eye reading and high intension for long-time work, and it cannot keep up with the demand of the increasing digitization and the IT age. Therefore, the dissertation proposes an improvement method to make up the above disadvantages of universal tool maker's microscope.On the basis of summarizing the current study of size measurement and relative technologies both in domestic and abroad, this dissertation develops a universal tool maker's microscope measuring system based on machine vision. The system mainly consists of the optical grating length measuring system, optical system, servo drive system, image collection system and host computer. The dissertation introduces the structure and the measuring principle of the system, develops step motor controller and blending step motor driver based on L297/L298 chip. The image processing technology is dealt with detailedly. In the image preprocessing, the dissertation analyzes results of several kinds of smoothing filter. Median filter stands out for its good edge maintenance and adaptability. The dissertation takes median filter as the way to process the collected image. Also, it uses histogram thresholding arithmetic to segment image. Analyses the classical edge detectors, and puts forward the edge detection method based on binary connected component. It not only makes use of segmentation image, but also enhances the detection speed. In the given application situation, this method completely satisfies demand and has superiority. In order to resolve the problem of edge lost and directions difference, the dissertation puts forward the annular arithmetic of profile trace and matches the direction of profile so that the measurement can fulfill successfully. Programs and debugs with C++ builder advanced language for the measurement of small accessory. Finally, makes some experiments on this system, and analyzes the systematic error.