Vision-based weld pool surface geometry measurement system for pulsed-GMAW process

Measurement of the three-dimensional weld pool surface geometry in GMAW process provides an essential approach to understand and future control of the complex welding process. In this article, a vision-based weld pool surface geometry measurement system for pulsed-GMAW process is demonstrated. A grid laser pattern is projected onto the liquid weld pool surface during the welding process. The laser reflected from the weld pool surface is intercepted by an imaging plane and the reflected pattern is captured by a high speed camera. Three-dimensional surface geometry is successfully reconstructed using an iteration-based reconstruction algorithm from captured pattern. Experiments on test target with known dimensions and in real welding processes were conducted. Reconstruction algorithm error was evaluated by comparing the measured geometry of test target and real target dimensions. The reconstruction result demonstrated that the error was within 10%.