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Near Field Acoustic Holography
Compressed Sensing for Near Field Acoustic Holography
What is Near Field Acoustic Holography ?
Near Field Acoustic Holography (NAH) aims at reconstructing the vibro-acoustic field of a structure from a recording of the close wave field emmited by the vibrating structure. The wave field recorded is then numerically time reversed to reconstruct the distribution of the sources on the source plan. NAH is widly used for the vibration monitoring and control within car industry and aeronautics
Two main difficulties come with this technique :
1) the necessity of using a regularization procedure (to compensate the low pass filtering effect from the propagation)
2) the high number of measures to fulfill Shannon-Whittaker sampling theorem.
Our goal in ECHANGE
We take advantage of the sparse nature of the acoustic wave to apply CS at NAH.
Recording of a vibrating structure
After building a theoretical framework and specifying the geometry of CS microphone arrays for NAH we ran experiments with a 120 microphone array.
The use of a priori information on the sparse nature of the acoustic wave increased the quality of the results, decreased the acquisition time and the number of sensors used in the experiment.
The experiments ran so focused first on a rectangular plate, then on more complex shapes (like cutted circles or a guitar board).
Imaging the modes of a guitar board with Compressive Nearfield Acoustic Holography. See also NACHOS, our reproducible code for CS applied to NAH
(photo: B. Arnaldi)
Bibliography
Journal paper
- Gilles Chardon, Laurent Daudet, Antoine Peillot, François Ollivier, Nancy Bertin, Rémi Gribonval. Nearfield Acoustic Holography using sparsity and compressive sampling principles. Journal of the Acoustical Society of America, acoustical society of america, 2012.
Simulation and algorithmic aspects(in french)
- Chardon G., Peillot A., Daudet L., and Ollivier F., Le « Compressed sensing » pour l'holographie acoustique de champ proche - I : Aspects algorithmiques et simulations, Actes du 10ème Congrès Français d'Acoustique, Lyon, France 2010.
Experimental aspects (in french):
- Peillot A., Chardon G., Daudet L., and Ollivier F. Le « Compressed sensing » pour l'holographie acoustique de champ proche - II : Mise en oeuvre expérimentale, Actes du 10ème Congrès Français d'Acoustique, Lyon, France 2010.
Code & data for reproducible research
