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ECOLE SUPÉRIEURE D'ÉLECTRICITÉ Une grande école d'ingénieurs au cœur des sciences de l'information,de l'énergie et des systèmes |
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Eddy current testing of anomalies in conductive materials. II. Quantitative imaging via deterministic and stochastic inversion techniques
Abstract : This analysis of eddy current testing of defects in conductive materials is divided in two parts. Part I [l]was devoted to reflection-mode diffraction tomography imaging tech- niques. Part I1 discusses application of deterministic and sto- chastic quantitative inversion techniques to similar configurations, and heavily draws upon Part I for physics and calculations of the eddy currents. The defects are modeled as cy- lindrical inhomogeneities concealed within a homogeneous non- magnetic metallic half-space. Values of the conductivity within the anomaly cross section have to be retrieved from multifrequency anomalous fields observed on a line above and parallel with the surface on the damaged block when a known time-harmonic source illuminates the block. Such quantitative imaging involves the ill-posed inversion of a Fredholm first-kind integral equation with exponentially damped kernel and requires some kind of regularization. Two approaches are fo- cused upon. In a deterministic context, an iterative algorithm provides a regularized generalized inverse, with the inconvenient that the stopping parameter should be appropriately chosen. In a stochastic context, Kalman filtering rapidly yields a good estimate of the conductivities, which could be the start- up of a more precise but costlier solution.
https://hal-supelec.archives-ouvertes.fr/hal-00643934
Contributor : Dominique Lesselier <>
Submitted on : Wednesday, November 23, 2011 - 12:07:53 PM
Last modification on : Friday, December 20, 2019 - 11:48:07 AM
Contributor : Dominique Lesselier <>
Submitted on : Wednesday, November 23, 2011 - 12:07:53 PM
Last modification on : Friday, December 20, 2019 - 11:48:07 AM
