Localisation de source en milieu réverbérant par Retournement Temporel

Abstract : In this thesis, the Time Reversal Process is applied in the acoustic domain, first to focus a few seconds-long random noise in a reverberant room, and second to localize impacts given at the surface of thin plates. Concerning the first application, 2D numerical simulations as well as 3D experiments show a spatial focusing of the signals. The signal to noise ratio is proved theoretically and experimentally to depend only on the number elements of the Time Reversal Mirror. The robustness of this focusing is studied while the medium reciprocity is broken between the two Time Reversal steps.
Moreover, a technique is developed to localize impacts given at the surface of reverberant plates. It is based on the pattern matching of acoustic signatures. The link between this method and Time Reversal, and the study of the waves excited by such impacts allow to predict the resolution and the signal to noise ratio of the technique. The interaction of the predominant wave (the A0 Lamb wave) with the plate's borders is studied. Besides, a finite differences simulation of A0 mode propagation in thin plates is developed. At last, the sensibility of the localization technique to temperature variations is studied in many materials, numerically, theoretically and experimentally. When temperature changes, the impulse responses are simply stretched, which can easily be compensated for.
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Contributor : Guillemette Ribay <>
Submitted on : Friday, December 29, 2006 - 4:26:36 PM
Last modification on : Thursday, July 4, 2019 - 11:00:03 AM
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  • HAL Id : tel-00122345, version 1

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Guillemette Ribay. Localisation de source en milieu réverbérant par Retournement Temporel. Acoustique [physics.class-ph]. Université Paris-Diderot - Paris VII, 2006. Français. ⟨tel-00122345⟩

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