QUANTITATIVE EVALUATION OF WELD DEFECTS BASED ON OVERALL SHAPE THREE-DIMENSIONAL RECONSTRUCTION

The evaluation of the size of weld defects is crucial in assessing the quality of weld structures. In this study, a novel quantitative evaluation method for weld defects was proposed based on 3D reconstruction using slices. The method includes two significant contributions. First, the supervised defect segmentation method was introduced, which uses the results of the previous slice to supervise the segmentation of the current slice based on slight changes in adjacent defect slices. This ensures accurate segmentation of all defects. Second, the subpixel edge extraction method combining the Canny operator and cubic spline interpolation was proposed to improve the accuracy of edge detection. The proposed method was evaluated using 15 defects. The experimental results showed that the average errors of inclusion defects, incomplete-penetration defects, and incomplete-fusion defects were 13.6%, 8.18%, and 13.9%, respectively. Compared with the other methods, the proposed method not only had higher accuracy but also provided the volume value of defects.