基于视觉特征的厚板机器人焊接焊缝轮廓的有效提取  

Effective Weld Seam Profile Extraction via Visual Features for Robotic Welding with Thick Steel Plates

作　　者：何银水[1] 余卓骅[2] 李健[1] 马国红[1] HE Yinshui;YU Zhuohua;LI Jian;MAGuohong(Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province,Nanchang University, Nanchang 330031;Institute of Technology. East China Jiao Tong University, Nanchang 330100)

机构地区：[1]南昌大学江西省轻质高强结构材料重点实验室,南昌330031 [2]华东交通大学理工学院,南昌330100

出　　处：《机械工程学报》2019年第17期56-60,共5页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51665037)

摘　　要：基于结构光的主动视觉传感技术是用于厚板机器人自动焊接中检测焊缝信息的一种有效途径。针对焊接过程中采集的焊缝图像包含或不包含电弧区域的两种情形,提出了一种基于视觉特征的适用于典型接头的激光条纹提取的通用算法。该算法利用Gabor滤波生成方向特征图,阈值分割后利用最近邻聚类算法对激光条纹和干扰数据进行聚类,根据聚类结果获得各类数据点在图像中的空间跨度,且只保留跨度值大于平均跨度的类,实现激光条纹的粗略提取;在从粗略提取结果中获取首个激光条纹分段的前提下,利用后续待识别的类与前一次已提取的激光条纹分段的欧式距离和类的自身跨度,设计了一个能提取激光条纹后续分段的竞争策略,从而实现激光条纹主体轮廓的准确提取;根据激光条纹视觉投射特点,设计了一个提取主体轮廓各分段之间的激光条纹细节的有效规则,实现激光条纹细节的提取。利用厚板T形接头和对接接头焊接中采集的焊缝图像验证了文中激光条纹提取算法的有效性,为厚板机器人自主焊接智能系统面向多种接头焊接应用的集成提供了可能。The active visual sensor system based on structured-light is an effective method to detect weld seam profiles used in robotic automatic welding with thick steel plates. A general algorithm is presented to extract the typical laser stripes via visual features from the images with or without entire arc regions, which contains three steps as follows. Gabor filtering with appropriate filtering angles is used to produce the orientation feature map, which is segmented by Otsu algorithm and clustered via nearest neighbor clustering. The clusters whose lengths are over the average one are kept whereas those clusters with small lengths are eliminated, through which the approximate major parts of the laser stripe are first extracted. The first part of the laser stripe is discerned through the visual features of the laser stripe from the above approximate extraction result. By using the discerned part a competitive strategy that can guide how to discern subsequent parts of the laser stripe step by step, is developed. The strategy depends on two factors一the Euclidean distance between the candidate clusters and the last discerned cluster, and the lengths of every cluster, through which the major parts of the laser stripe can be then extracted. A rule of how to identify the small parts that lie between two adjacent major parts of the laser stripe is investigated. To verify the effectiveness of the proposed method, two types of images that are captured in the welding process with T-joints and butt joints, are applied to the tests. The proposed method affords the possibility of integrating different functions into an intelligent robotic welding system for weld profile extraction with different joints.

关 键 词：激光条纹提取 视觉特征 厚板焊接 聚类 方向特征图 

分 类 号：TG409[金属学及工艺—焊接]