Electromagnetic Non Destructive Evaluation and Inverse Problems

This thesis is focused on Eddy Current Testing (ECT), a technique for the Non Destructive Testing of conductive materials. In particular we study the quantitative imaging (inverse problem) of defects in conductive materials. By quantitative imaging we means imaging methods based on numerical models of the interaction between the probe and the defect(s). The imaging methods attempt to provide an image of the defect at variance of commercial instruments that, generally, detect the defect and may have limited capabilities of extracting its major sizes by means of calibration curves obtained in predened conditions. In addition, numerical models of the probe-defect interaction (direct problem) play a relevant role for the computer aided design of the probe, where commercial codes typically fail to treat this kind of problems. In this thesis we present methods for the solution of both the direct and the inverse problems in ECT. The methods have been developed ad-hoc for ECT and have been optimized for accuracy and speed in view of real-time applications.