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This paper presents a physics-based filtering scheme for passive underwater acoustics. The algorithm focuses on moving ship noise and single receiver configuration. It allows to denoise the received spectrogram and to separate the contributions of two different moving ships. The proposed method considers filtering the 2D Fourier transform of the received spectrogram. The filter design is based on the waveguide invariant principle and on some a priori knowledge on the oceanic waveguide. The noise nature on the spectrogram is taken into account by introducing a non-linearity to the filtering scheme. The algorithm thus corresponds to a nonlinear homomorphic filter. The method is validated on both simulated data and experimental marine data.
RÉSUMÉ
Cet article présente une méthode de filtrage adaptée à l’écoute passive monocapteur du bruit rayonné par des navires en mouvement dans un environnement océanique petit fond. Elle permet d’améliorer le rapport signal à bruit et de séparer les contributions de deux navires dans le plan temps-fréquence. La méthode exploite le principe de l’invariant océanique ainsi qu’une faible connaissance a priori des célérités du canal océanique pour réaliser le filtrage dans le domaine de la transformée de Fourier 2D du spectrogramme. La nature du bruit sur le spectrogramme est également prise en compte en incorporant une non-linéarité au filtrage. Les performances du filtrage sont évaluées sur données simulées respectivement pour le dé-bruitage et pour la séparation de navires. Les résultats obtenus mettent en évidence les bonnes performances du débruitage et de la séparation. Des exemples de résultats sur données réelles attestent de l’efficacité du filtrage.
underwater acoustics, ship noise, spectrogram, filtering, 2D Fourier transform, signal separation, denoising, homomorphic filter
MOTS-CLÉS
acoustique sous-marine, bruit de bateau, spectrogramme, filtrage, transformée de Fourier 2D, séparation de sources, débruitage, filtre homomorphique
Aviyente S., Williams W. (2006). Multitaper marginal time–frequency distributions. Signal Processing, vol. 86, n° 2, p. 279-295.
Boashash B. (2003). Time frequency signal analysis and processing: a comprehensive reference. Elsevier Science.
Chuprov S. (1982). Interference structure of a sound field in a layered ocean. Ocean Acoustics, Modern State, p. 71-91.
Cockrell K., Schmidt H. (2010). Robust passive range estimation using the waveguide invariant. The Journal of the Acoustical Society of America, vol. 127, p. 2780.
Cockrell K., Schmidt H. (2011). A modal wentzel-kramers-brillouin approach to calculating the waveguide invariant for non-ideal waveguides. The Journal of the Acoustical Society of America, vol. 130, p. 72.
Cockrell K., Schmidt H. et al. (2010). Understanding and utilizing waveguide invariant rangefrequency striations in ocean acoustic waveguides. Thèse de doctorat non publiée, Massachusetts Institute of Technology.
Djuric P., Kay S., Vijay K., Douglas B. (1999). Spectrum estimation and modeling. Digital Signal Processing Handbook.
Gervaise C., Kinda B., Bonnel J., Stéphan Y., Vallez S. (2012). Passive geoacoustic inversion with a single hydrophone using broadband ship noise. The Journal of the Acoustical Society of America, vol. 131, n° 3, p. 1999-2010.
Heaney K. (2004). Rapid geoacoustic characterization using a surface ship of opportunity. Oceanic Engineering, IEEE Journal of, vol. 29, n° 1, p. 88-99.
Hildebrand J. (2009). Anthropogenic and natural sources of ambient noise in the ocean. Marine Ecology Progress Series, vol. 395, n° 5.
Jensen F., Kuperman W., Porter M., Schmidt H. et al. (2011). Computational ocean accoustics, second edition.
Kay S. (1988). Modern spectral estimation: theory and application (vol. 29). Prentice Hall Englewood Cliffs, NJ.
Mari J., Coppens F. (2000). Sismique de puits, chapitre 4. Institut Français du Pétrole, Editions Technip.
Ogden G., Zurk L., Jones M., Peterson M. (2011). Extraction of small boat harmonic signatures from passive sonar. The Journal of the Acoustical Society of America, vol. 129,p. 3768.
Oppenheim A., Schafer R., Stockham Jr T. (1968). Nonlinear filtering of multiplied and convolved signals. Audio and Electroacoustics, IEEE Transactions on, vol. 16, n° 3, p. 437-466.
Pekeris C. (1945). Theory of propagation of explosive sound in shallow water. Office of Scientific Rechearch and Development, National Defence Research Committee.
Pitas I., Venetsanopoulos A. (1986). Nonlinear mean filters in image processing. Acoustics, Speech and Signal Processing, IEEE Transactions on, vol. 34, n° 3, p. 573-584.
Ross D. (1976). Mechanics of underwater noise. Rapport technique. DTIC Document.
Simard Y., Lepage R., Gervaise C. (2010). Anthropogenic sound exposure of marine mammals from seaways: Estimates for lower st. lawrence seaway, eastern canada. Applied Acoustics, vol. 71, n° 11, p. 1093-1098.
Sorensen E., Ou H., Zurk L., Siderius M. (2010). Passive acoustic sensing for detection of small vessels. Proceedings of MTS/IEEE OCEANS 2010 Seattle, p. 1-8.
Stergiopoulos S. (2000). Advanced signal processing handbook: theory and implementation for radar, sonar, and medical imaging real time systems. CRC Press.
Turgut A., Orr M., Rouseff D. (2010). Broadband source localization using horizontal-beam acoustic intensity striations. The Journal of the Acoustical Society of America, vol. 127,p. 73.