The detection of flaws that involve 5&percent; or more of the pipe wall thickness is not easy to achieve for internal defects inspected from the outside. In this work we focus on a relatively straightforward technique, based on obtaining the characteristic signature of relevant defects, and projecting the actual signals on these “standard” defect configurations, thus increasing the signal‐to‐noise ratio and providing an alternative way to determine the nature of the defect. Several options are discussed, including some that are computationally less demanding, and are susceptible of being implemented on‐line. © 2003 American Institute of Physics