Noniterative Methods for Real Time Imaging of Conducting Materials

Real-time imaging is a either a mandatory or an attractive feature in practical applications of Nondestructive Evaluation of structures and materials. To date, real-time imaging in commercial systems is achieved only by means of calibration charts or pre-computed databases containing the "signatures" corresponding to a finite number of defect configurations and inspection parameters. Situations beyond these sets of signatures cannot be treated and may cause misinterpretations of the data. This paper is a review on the electromagnetic imaging of defects in conducting materials by Noniterative Imaging methods. The class of Noniterative Imaging methods has attracted considerable interest because is suitable for real-time imaging. The paper discuss in detail the Monotonicity Imaging Method (MIMe), that is a specific Noiterative Imaging method successfully applied in Electrical Resistance Tomography and Eddy Current Tomography.