Tracking a defect in the multiple scattering regime

Thomas Planes (1) , Éric Larose (1) , Vincent Rossetto (2) , Ludovic Margerin (3)

1 Ondes et Structures
2 LPM2C - Laboratoire de physique et modélisation des milieux condensés
3 IRAP - Institut de recherche en astrophysique et planétologie

We describe a time-resolved monitoring technique for heterogeneous media, especially multiply scattering media. Our approach is based on the spatial variations of the cross-coherence of diffuse waves acquired at fixed positions but at different dates. The technique applies to all kind of waves, but a particular attention will be paid to ultrasound propagating in concrete. To locate and characterize a defect occurring between successive acquisitions, we use a maximum likelihood approach combined with a diffusive propagation model. We quantify the performance of this technique called LOCADIFF with numerical simulations. In several illustrative examples, we show that the change can be located with a precision of a few wavelengths and that its effective scattering cross-section can be retrieved. We investigate how the accuracy and precision of the method depends on the number of source-receiver pairs, on the time window used to compute the cross-correlation and on the errors in the propagation model. Applications can be found in nondestructive testing (civil engineering), seismology, radar, and sonar location.

Domains: Geomorphology

Thomas Planes, Éric Larose, Vincent Rossetto, Ludovic Margerin. Tracking a defect in the multiple scattering regime. Journal of the Acoustical Society of America, 2011, 130 (4), p.2378. ⟨10.1121/1.3654534⟩. ⟨insu-00682000⟩