Abstract: A novel method of seam center detection based on the welding visual image centroid is presented. Based on the weld pool image centroid arithmetic and CCD work principle, a centroid model whose characteristic corresponds with the centroid value, workpieces temperature field and the seam center position is established. The model numerical solution under a certain welding condition can be acquired after the welding temperature field is numerically simulated. The analysis result of model influence factors indicates that the factors such as welding current, traveling velocity and seam width influence the model apparently. Experiment formula is obtained accord-ing to the tendency analysis of model solution. Also, the least-square method is employed to build the specimen spatial data according to various welding parameters. Then the par-ticular parameters of model are obtained according to multi-linear regressive analysis. Therefore, the centroid-offset formula with actual welding parameters is acquired. It is shown by actual welding experiments that the welding position can be detected by using the image centroid arithmetic.

Key words: Detection, Seam center, Image centroid, Model