改进Canny算子下的工件尺寸测量

Workpiece size measurement under improved Canny operator

针对人工用游标卡尺测量手工捏花尺寸效率低下的问题,提出一种改进的自适应Canny算子测量手工捏花尺寸的方法。首先,引入均值漂移法分割图像,图像颜色变得渐变、细纹纹理平缓;其次,用大致轮廓的平均像素值选择性的替代边缘检测的高阈值,以达到较好的自适应提取边缘的目的;再次,scharr算子代替sobel算子,增强了弱边缘的提取能力;最后,去掉小型连通域并且用主成分分析方法(PCA)获取轮廓的主方向,求取主方向直线方程,通过轮廓点在该直线上的最大投影距离获得捏花的长度,轮廓点在该直线的垂直方向上的最大投影距离获得捏花的宽度。实验表明,在对不规则物体的识别率上,本文方法比其他方法有着显著的提升,准确率达到97%,与真实值误差2 mm左右,并且通过强光、弱光、侧面光实验对比分析,该方法受光照影响较小,满足工业自动化需求。

Aiming at the low efficiency of measuring the size of a manual pinch with a vernier caliper, an improved adaptive Canny operator is proposed to measure the size of a manual pinch. Firstly, the mean shift method is introduced to segment the image, and the image color becomes gradual and the fine grain texture is gentle. Secondly, the average pixel value of approximate contour is selectively used to replace the high threshold of edge detection, to achieve the purpose of better adaptive edge extraction. Thirdly, Scharr operator replaces Sobel operator to enhance the ability of weak edge extraction. Finally, the small connected domain is removed, and the principal direction of the contour is obtained by principal component analysis(PCA), and the straight-line equation of the principal direction is obtained. The length of the pinch is obtained by the maximum projection distance of the contour point on the straight line, and the width of the pinch is obtained by the maximum projection distance of the contour point in the vertical direction of the straight line. Experiments show that this method has significantly improved the recognition rate of irregular objects more than other methods, with an accuracy of 97% and an error of about 2 mm from the real value. Through the comparative analysis of strong light, weak light and sidelight experiments, this method is less affected by light and meets the needs of industrial automation.