State-of-the-Art of Weld Seam Inspection by Radiographic Testing: Part I ΠImage Processing

Over the last 30 years, there has been a large amount of research attempting to develop an automatic (or semiautomatic) system for the detection and classification of weld defects in continuous welds examined by radiography. There are basically two large types of research areas in this field: image processing, which consists in improving the quality of radiographic images and segmenting regions of interest in the images, and pattern recognition, which aims at detecting and classifying the defects segmented in the images. Because of the complexity of the problem of detecting weld defects, a large number of techniques have been investigated in these areas. This paper represents a state-of-the-art report on weld inspection and is divided into the two parts mentioned above: image processing and pattern recognition. The techniques presented are compared at each basic step of the development of the system for the identification of defects in continuous welds. This paper deals with the first part.