Radioscopic Images Segmentation by “Edge and Area” Combined Approach for Weld Geometric Characterization

Abstract The present paper deals with the geometric characterization of a circumferential weld bead by radioscopy. Weld control can only be performed by tangential irradiation. The series of images obtained by projection, for one rotation of the welded component, is then strongly degraded, as each image contains the projected section of the weld and the superposition of several other sections. The inverse problem is solved using a new image segmentation method, based on an “edge and area” combined approach. The edge approach defines the limits of the weld molten zone by minimum gradient points. The area approach uses a thresholding method based on histogram analysis to position the bottom of the bead exactly. This segmentation leads to fast and automatic control of the weld quality. A validation stage on industrial components shows the method reliability.