Detection of weld defects by computer-aided x-ray radiography image processing

The X-ray radiographic testing method is often used for detecting weld defects as a nondestructive testing method (NDT). Due to the difficulties in identifying small defects from the X-ray film, skilled labourers should be trained. However, recently it has been difficult to employ skilled labourers. Moreover, for the identification process, not only the labourers' skill influences the testing result, but also it is difficult for skilled labourers to assess small flaws within a short time. In comparison, computer visual image processing systems have some good characteristics, allowing objective assessment, high-speed judgment, nonhuman error, etc. Therefore, an image processing system allows weld defects to be detected using X-ray radiography in the presence of background noise. This paper deals with an image processing method for detecting defects, such as pores, slag inclusions and cracks, and discusses a system of displaying defects by computer graphics.