Advances in the field have enabled ultrasonic C-scan imaging to go bey
ond its classical application of detecting large single flaws to meet
the challenge of non-destructive evaluation for modern engineered stru
ctures and new materials. Increased frequency of operation and novel t
ransducer designs have led to micrometre resolution limits for both su
rface and subsurface imaging. Improved image processing and analysis m
ethods allow more information to be extracted from the classical and c
ontemporary application of the C-scan technique. Important results and
developments are discussed with references made to industrial applica
tions.