A low-cost vision system for open arc welding based on multi-exposure

Abstract

In order to get real-time visual information about the extremely bright weld arc and the neighboring dark areas in the open arc welding process, a low-cost vision system is proposed. The vision system contains three main components: a single off-the-shelf CCD/CMOS digital camera, a welding glass and an IPC (Industrial Personal Computer). A software-based method of capturing multiexposure images is investigated; it changes exposure gain and shutter time by sending exposure parameters through PC program. By using software trigger method, the system captures sets of two exposures, such as “dark”, “light”, repeatedly. To obtain an image with sufficient details of the weld process, a simple and little time-consuming algorithm which adds every two continuous multi-exposure images is discussed. The approach can render videos of 640 by 480 pixel resolution at up to 22 frames per second.