Image pos-processing and inversion for eddy current crack detection problems

This paper describes how field invariances due to the geometrical properties of the excitation coil enhance the determination of different parameters of defects. Two probes, one circular and another with a parallelepiped shape, are used to detect and analyze cracks in an aluminum plate. The geometrical characteristics of these probes are used to improve the interpretation of the image signals obtained when a plate is scanned. A quite simple direct model based on a conformal mapping is obtained and used to seek for the solution of the inversion problem, when the parallelepiped probe is under use. The image processing algorithms results are compared with the experimental data acquired when a linear defect in a conductive plate is scanned.

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