Eddy current testing of anomalies in conductive materials. I. Qualitative imaging via diffraction tomography techniques

The authors consider the analysis of eddy current testing of defects in conductive materials. The authors investigate the application of reflection-mode diffraction tomography (DT) imaging techniques. First, exact synthetic data are calculated for various canonical configurations using a method of moments, and they are compared with those calculated by a finite-element code and with experimental data. Analysis of these data in particular evidences interest and some limitations of the Born approximation. Second, two imaging algorithms are proposed and investigated from numerical simulations; the first directly originates from ultrasonic DT where most of the attenuation is neglected, and the other approximately accounts for the skin effect