On attenuation-matched inversion methods of diffusive wavefields

Amelie Litman (1) , Dominique Lesselier (1)

1 L2S - Laboratoire des signaux et systèmes

The non-destructive evaluation of a defect affecting a metal half-space from the observation of electromagnetic diffusive wavefields observed from above in air is considered within a linearizing assumption of the wave phenomenon. Emphasis is on appropriately solving a coupled Fourier-Laplace transform in order to map the conductivity contrast of the damaged block. To do so, two related `optimal' solution methods are developed. The first one makes use of an exponential sampling both of the observation frequency bandwidth and of the depth extent of the search domain, and the second is based on an appropriate calculation of a weighted generalized solution. Synthetic results illustrate the features of these two solution methods for a variety of defect configurations, in particular they show that support information acquired in an iterative fashion allows zooming onto the defect. Comparisons with known diffraction tomographic schemes are also carried out. Extensions of the solution methods are proposed and the fact that nonlinearized inversion schemes may benefit from a sampling matched to the attenuation is underlined.

Amelie Litman, Dominique Lesselier. On attenuation-matched inversion methods of diffusive wavefields. Inverse Problems, 1999, 15 (1), pp.99-111. ⟨10.1088/0266-5611/15/1/014⟩. ⟨hal-00438281⟩