Study of 3D Reconstruction of Laser Welding Pool Surface Based on Shape from Shading

Abstract

Shape from shading (SFS) is one of the critical techniques in 3D shape recovery in computer vision. The task of SFS is to reconstruct 3D shape of the visible surface of an object from one single picture using its gray variation. Analyzing the 3D shape of welding pool is important to evaluate the welding quality. During the disk laser welding experiments, a high-power laser was used as the auxiliary illuminant, and a high-speed image acquisition system with infrared filter was applied to capture the welding pools in real time. The slant and tilt of illuminant source were estimated by statistics to reconstruct the 3D shape of welding pool visible surface by using the localization method of SFS. Methods of median filter and cubic spline interpolation were used to denoise images and smooth the image shapes. Experimental results showed that the proposed technique could reconstruct parts of welding pool effectively.