Intelligent sensing for non-destructive testing using eddy currents

When a metallic surface is tested by the eddy-current technique, defects produce events on the electrical signal coming from the sensor whose particular signature is a function of different factors such as the shape, size and position of any defects. Thanks to the introduction of modern digital signal processing methods, the quality of detection of events in the signal may be appreciably improved. The reliability of the decision mechanism, entrusted with reducing non-detection and limiting false alarms, is then increased and allows consideration of automatic testing. The work presented here was done jointly by the Institut de Recherches de la Sidérurgie Française (IRSID) of the Usinor-Sacilor group and the aboratoire d' Automatique et de Recherche Appliquée (LARA) of the Centre de Recherche en Automatique de Nancy (CRAN).