Automatic inspection techniques by real time radiography for weld defects

The technical level of present real time radiography inspection system was analyzed with the evaluation of real time radiography techniques for weld defects. Image preprocessing methods were introduced for image enhancement and noise elimination. Defect extraction techniques were studied with an effective weld boundary extracting algorithm developed based on gray level. A DSA method based on background fitting for isolated weld seams was proposed for feature extraction with the concept of correlativity modification put forward for the extraction results. Automatic recognition techniques for weld defects were also studied. These techniques were then combined into a real time radiographic inspection system for weld defects.