Visual recognition of the initial and end points of lap joint for welding robots

This paper describes a recognition method for the initial and end points of lap joints based on the image processing techniques. The edge detection technique is used in order to find the edges of the image. And the image processing techniques are employed in order to link the broken edges and find T-junctions of the image which are determined as candidates for the initial and end points of the weld seam. The T-junctions that match the conditions of angles checking and coordinate comparing will be detected as initial and end points of weld seam. The proposed method mainly insists of the 4 steps namely 1) smoothing the image and extracting edges of the image by using Canny operator 2)linking broken edges 3)detecting T-junctions and 4)analysing the initial and end points of weld seams. The experimental results showed that the initial and end points of the lap joints can be precisely recognized using the methods proposed in this paper.