Weld pool edge detection for automated control of welding

A vision system that determines the edges of the weld pool in sequences of gas-tungsten-arc welding images acquired by a coaxial viewing system is described. The vision system uses a transformation that maps the edge of a weld pool into a vertical line. The weld pool edge is detected in the transform domain by using a directional filter, which retains only intensity changes of interest, and a one-dimensional edge detector. The edge of the weld pool, in the physical domain, is determined using the inverse transformation. The transformation uses parameters that are updated when processing a sequence of images, and are initially determined by analyzing the first image frame in the physical domain