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LE PUITS À RETOURNEMENT TEMPOREL DANS LE DOMAINE AUDIBLE : UN OUTIL DE FOCALISATION ET D'IMAGERIE À HAUTE RÉSOLUTION DE SOURCES SONORES ET VIBRATOIRES

Abstract : Developing new high resolution focusing and imaging techniques for audible vibrational and acoustic sources is an important problem to solve in acoustics. Methods of this kind are notably useful to locally excite and analyse complex vibroacoustic structures with high resolution capabilities, which is particularly important when the size of the studied objects is smaller than the wavelength. The desired technique should be fast, accurate, flexible, and non-invasive. This technique must be used to study both vibrational and acoustic sources. This work shows the development of such a technique, based on the time reversal sink, which has been sofar only implemented for ultrasonic and electromagnetic waves focusing (not for imaging). The time reversal sink method is extended to hyper-resolution focusing for low frequency acoustic sources. This method provides a way to excite locally a structure with high intensity and high resolution capabilities, even at low frequency. However, we show that this method is difficult to implement in real world cases becauses it is an invasive focusing technique. Nevertheless, we present in this manuscript a new imaging technique of vibrational and acoustic sources, based on the time reversal sink. This is a new non-invasive technique, with high resolution capabilities. This technique uses the same array measurement techniques than beamforming and near-field acoustic holography, and provides an elegant and powerful way to obtain high resolution images of vibrational and acoustic sources at low frequency. This new method is extensively described and analysed, and applied to impact sources on a clamped plate, acoustic sources in a free field configuration and underwater acoustic sources in a deep water channel. This method has also been applied to the imaging of acoustic sources on a classical guitar. The results presented show high resolution, fast and reliable capabilities of this new powerfull imaging technique, that shows similar capabilities than those of nearfield acoustic holography and better results than those of beamforming and time reversal backpropagation at low frequency.
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https://tel.archives-ouvertes.fr/tel-00811601
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Submitted on : Wednesday, April 10, 2013 - 5:06:26 PM
Last modification on : Wednesday, February 10, 2021 - 10:32:07 AM
Long-term archiving on: : Thursday, July 11, 2013 - 4:17:25 AM

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  • HAL Id : tel-00811601, version 1

Citation

Eric Bavu. LE PUITS À RETOURNEMENT TEMPOREL DANS LE DOMAINE AUDIBLE : UN OUTIL DE FOCALISATION ET D'IMAGERIE À HAUTE RÉSOLUTION DE SOURCES SONORES ET VIBRATOIRES. Acoustique [physics.class-ph]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨NNT : 2008PA066395⟩. ⟨tel-00811601⟩

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