The main objective in ultrasonic defect evaluation is to locate and cl
assify suspect flaw indications quickly and accurately. Since the volu
me of data to be assessed can be very large, traditional forms of defe
ct evaluation involving a skilled human interpreter are often unsuitab
le. The progress in the automated evaluation of ultrasonic data has be
en considerable in recent years and this paper outlines some of the ap
proaches adopted in this area. Traditional pattern recognition techniq
ues and the currently popular neural network approaches have been wide
ly employed to process feature sets, extracted from A-scan signals. Kn
owledge-based system techniques, although not so widespread, are also
considered. A number of authors have taken the approach that such AI t
echniques should be embedded in an integrated software framework for d
efect evaluation, and this is also discussed.