Automatic image processing in radioscopic testing

The 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 for one rotation of the welded component is then strongly degraded. 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 exactly position the bottom of the bead. This segmentation leads to fast and automatic control of the weld quality.