中文摘要：

针对旋转电弧窄间隙熔化极活性气体保护焊多层单道焊焊缝跟踪需要，提出一种基于被动视觉传感的焊缝偏差识别方法．首先通过旋转电弧位置传感器和处于触发工作模式的CCD摄像机获取电弧旋转到坡口左侧和坡口右侧时的焊接图像，然后根据图像灰度直方图特点，构建了自适应双阈值获取算法．大阈值用于获取电弧区域进而得到电弧中心位置；小阈值用于获取坡口工件区域，进而通过计算水平方向一阶差分得到坡口边缘．通过对比一个电弧旋转周期内获取的两幅图像，可计算电弧旋转中心和坡口中心的偏差，得到焊缝偏差．该偏差检测算法高效、可靠且可避免坡口底部改变带来的误差，同时可用于不同偏差算法的比较和融合．

英文摘要：

Aimed at welding seam tracking of multi-layer single pass welding by narrow gap rotating arc MAG, a passive vision sensing based welding deviation detection algorithm was proposed. First,the weld- ing image was obtained by the welding position sensor and the CCD camera in trigger mode when the rota- ting arc was on the left or right side of the groove. Second, two adaptive thresholds were computed accord- ing to the grayseale histogram of the welding image. The large threshold was used to obtain the are region and the arc central location. The small threshold was used to obtain the base metal area of the groove, and the edges of the groove were obtained by calculating the horizontal direction first-order difference in special horizontal positions. Finally, by comparing the image process result of two images in each rotation arc cy- cle, the welding deviation, i.e. the difference between the center of arc rotating and the center of the groove, were obtained. The deviation detection algorithm is efficient and reliable. It can avoid the interfer-ence of the variation of the groove bottom, and be used for comparison or integration with other deviation detection algorithms.