Research on 3D imaging and sub pixel quantitative method of weld defects

DOI:	10.11809/bqzbgcxb2024.03.029
Keywords:	phased array ultrasonic testing; segmentation of weld defects; 3D model; subpixel edges; quantitative analysis
Abstract:	In order to achieve accurate and quantitative analysis internal defects of welds which are used in industrial equipment, a segmentation algorithm based on image’s color was proposed to process defect slices and obtain their length through rebuilding their three dimensional model, aiming at the problem of insufficient accuracy in quantitative analysis caused by over segmentation and under segmentation of the defect images when constructing a three dimensional model for defects. Then, Canny operator with cubic spline interpolation was used to obtain subpixel edges of defects. Finally, a method for obtaining area and volume of defects based on Connected Component Labelling and accumulation method is proposed. The research results show that: compared with actual data, errors in length about lacking of penetration, lack of fusion and slag defects in three dimensional model are 8.18%, 5%, and 9.62%. Regions within the subpixel edge of defects are labeled to accurately obtain their area and volume. This method can instantly show internal defects’ shape and position without damaging weld’s structures, which lay a foundation for analyzing their area and volume.
Published:	2024-03-28
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