An automatic flaw classification method for ultrasonic phased array inspection of pipeline girth welds

The ultrasonic phased array (UPA) technique has rapidly become a new method in the industrial non-destructive testing (NDT) field for quality assessment and materials characterization by providing the distinct advantages of electronic beam-steering, sector scanning and dynamic focusing. The UPA testing system was composed of an auxiliary PC and a main PC. The former received parameters transferred from the latter through TCP/IP, controlled the hardware system to scan the weld and sent echo data to the main PC. The latter could be a desktop computer or a notebook and was in charge of system software settings, computation of the transmission delay law, displaying the received ultrasonic echoes and automatic identification of flaw echoes. If the echo was a test sample, the same flaw features were extracted according to the optimal flaw feature set and were input to the trained classifier. The output of the classifier was the type of the detected flaw.