Study on Machine Vision Measurement Method for Large-Size Workpiece Screw Hole
Based on the characteristic of corner positioning commonly used in the machining of threaded circular holes in 3C product shell workpieces,a method for measuring the position and size of threaded circular holes based on linear and circular feature positioning is proposed by utilizing the continuity of sub images captured by a linear array camera.The improved Hough linear localization method based on the fitting method and improved Hough transform circular detection method based on the multiplicative congruence method were used to achieve edge localization of 3C housing workpiece images and extraction of circular coordinates and diameter dimension measurement of threaded cir-cular holes.Based on the continuity of the image,the sub images were detected one by one and the starting pixels of adjacent sub images are accumulated to achieve the global detection of threaded round hole size in large size images.The above method ultimately achieves a measurement accuracy of±0.2220mm for the position and size of the threa-ded circular hole on large-sized 3C shell workpieces,and±0.0904mm for the aperture size.The detection time for a single workpiece is 33.737s.
Machine visionLarge size workpieceStraight line inspectionRound hole inspection
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