Analysis of 3D reconstruction algorithm of laser welding molten pool image

The molten pool in high-power disk laser welding is related to the welding quality.The welding molten pool images were captured by a laser welding monitoring system.In order to reconstruct 3D shapes of the welding molten pools and further analyze the relationship between the shape features such as weld bead height,weld bead width and the welding quality,the shape from shading (SFS) technology based on single welding molten pool image was researched.3D molten pool shapes could be recovered by the gray variations of welding molten pool image.The experimental apparatus included an auxiliary diode illuminant and a high-speed camera with near infrared filter to capture the welding molten pools in real time.The slant and tilt of illuminant source were estimated by the statistical algorithm.The 3D shape of welding molten pool surface was reconstructed by using the localization method of SFS.Also,the methods of median filter and cubic spline interpolation were applied to remove the noise and smooth the shape of molten pool.Experimental results showed that the proposed method can reconstruct the welding molten pool surface effectively.The 3D molten pool shape can be estimated by the molten pool image during high-power disk laser welding.