Simultaneous imaging and measurement of weld pool surface and metal transfer from weld pool reflected laser lines

Precision control of gas metal arc welding process requires both weld pool surface and developed/detached droplet be simultaneously measured from the same sensor. To this end, laser lines are projected onto the weld pool surface and the reflected laser lines are intercepted and imaged. It is found from the images that the reflected laser lines are intercepted periodically by the droplets. While this interception adds complexity to the clustering of laser lines but it also provides sources to simultaneously detect the geometry of the droplet. This paper aims at extracting the laser lines from images that contain the reflected laser lines and extracting the droplet from the interception points. Experimental results verified the effectiveness of both the proposed image processing algorithms and modelling methods. Since the weld pool surface and droplet are extracted from the same image, a method thus has been developed to simultaneously image and measure the weld pool surface and metal transfer process.