Abstract: The welding seam image gathered by an optical system composed of charge-coupled device(CCD) camera and composite filter technology for pipe-line back welding of metal active gas(MAG) is analyzed in a bid to extract the weld pool edge. Considering the effect of initial contour on Chan-Vese model, extract the rectangle representing the coarse location of molten weld pool by using the gray information after Gaussian smoother, and set the initial contour of Chan-Vese model at the center of the rectangle, then use the Chan-Vese model to extract the edge of the weld pool. Compared with the traditional methods, the experimental results show the precision of weld pool extraction is greatly improved.

Key words: Active contour, Chan-Vese model, Edge extraction, Weld pool control