Ultrasonic flaw classification: Focusing on features

All ultrasonic flaw classifiers require input features. Unfortunately, in many previous cases the choice of features in a particular domain has been done in a heuristic or purely statistical manner, resulting in less than optimal performance. We will review some of the domains and features that have been previously used, with special emphasis on ultrasonic weld flaw classification problems. We will also describe some of the issues involved in choosing and using features in classification problems.