Optimal imaging band selection mechanism of weld pool vision based on spectrum analysis

Based on the spectrum of self-emitted radiation of weld pool and the quantum efficiency of the camera, we deduce the relative response intensity of the camera to the self-emitted radiation of the weld pool and verify it with the spectrometer. Combined with arc spectrum properties, we propose the theoretical criteria for optimal imaging band selection, which is suitable to multiple welding processes and materials. Through analyzing the relationship between welding current and light intensity, we design a trigger method for weld pool image acquisition. Based on the theory, we select 850 nm high-pass filter and 660 nm band-pass filter to capture weld pool images of stainless steel GMAW plate welding. The captured images have clear texture, high signal-to-noise ratio, and abundant details, which verifies the feasibility of our theory. This paper provides theoretical guidance for the imaging bands selection in weld pool vision.