Parts Three-dimensional Measurement Based On Binocular Stereo Vision

Recent years stereo vision technology have been evolved fast, especially the three-dimensional measurement techniques based binocular stereo vision has been applied to a lot of industrial areas, such as the workpiece size measurement, intelligent obstacle avoidance and so on. Compared to traditional visual measurement technology, stereo vision technology has the advantages of high accuracy and speed. The research abroad in the field of stereo vision has made great breakthroughs, while the domestic research in this area is still in a relatively early stage.Therefore, this paper makes the binocular stereo vision as the subject and deeply studies current theoretical difficulties of binocular vision measurement, including camera calibration, image preprocessing, limit correction, stereo matching and three-dimensional reconstruction. This paper aims to solve existing deficiencies by studying these difficulties and be able to establish an effective measure system of binocular stereo vision. The main contents are as follow:1. Camera Calibration: The principles and theoretical model of binocular stereo camera calibration were studied in detail. The paper analyzed advantages and disadvantages of various types of methods in order to choose the most suitable one. Then the paper completed the camera calibration work of inside and outside parameters based on the Matlab computer vision tool box. The error s were analyzed to improve the calibration accuracy.2. Image Pre-processing: The paper was focused on several common image processing methods and the most suitable one was chosen. Meanwhile this paper studied the principle of polar-line correction and conducted polar-line correction experiment. The result verifies that through polar-line correction the interference of distortion, location and light has decreased significantly, thereby reducing the difficulty of the subsequent stereo matching and improving the processing speed.3. Stereo Matching: This chapter described the working principle of stereo matching and studied the selection method to choose the basic unit and constraint factors. Through analysis of the stereo vision matching principle, the paper established an effective model of binocular stereo vision, and made related experiment.4. Three-dimensional Reconstruction: The paper established the conversion relationship matrix from the world coordinate system to the image coordinate system. Then the three-dimensional coordinates formula of the actual point was deduced. After that through obtaining three-dimensional coordinate information of part feature points, the paper solved the size information of three-dimension and completed the three-dimensional reconstruction.In summary, this paper is based on the above theoretical research and compiled relevant algorithm of the feature points and stereo matching. Then the paper applied the software of Matlab to achieve the system development of binocular stereo vision measurement. Experimental results have shown that this system can effectively complete the three-dimensional measurement of the parts.