SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 05 Aug 2024 09:30:46 GMT2024-08-05T09:30:46ZThe parametric propagation in underwater acoustics : experimental results
http://hdl.handle.net/10985/8988
The parametric propagation in underwater acoustics : experimental results
BOUTTARD, Etienne; LABAT, Valérie; BOU MATAR, Olivier; CHONAVEL, Thierry
In underwater acoustics, detection of buried objects in sediments (cables, mines, . . . ) is a complex problem. Indeed, in order to ensure sufficient penetration depth in marine sediments, low frequencies have to be used, implying a low resolution. A solution proposed to solve this problem is the parametric emission based on the nonlinear properties of seawater. This method can generate a low frequency wave from two directional high frequencies beams. The aim of this work is to present experimental results of a parametric propagation. Experiments have been carried out in a water tank in various configurations. These experimental measurements are then compared with simulation results obtained with a numerical model based on a fractional-step method presented at the Underwater Acoustic Measurements conference in 2011.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/89882012-01-01T00:00:00ZBOUTTARD, EtienneLABAT, ValérieBOU MATAR, OlivierCHONAVEL, ThierryIn underwater acoustics, detection of buried objects in sediments (cables, mines, . . . ) is a complex problem. Indeed, in order to ensure sufficient penetration depth in marine sediments, low frequencies have to be used, implying a low resolution. A solution proposed to solve this problem is the parametric emission based on the nonlinear properties of seawater. This method can generate a low frequency wave from two directional high frequencies beams. The aim of this work is to present experimental results of a parametric propagation. Experiments have been carried out in a water tank in various configurations. These experimental measurements are then compared with simulation results obtained with a numerical model based on a fractional-step method presented at the Underwater Acoustic Measurements conference in 2011.Psi_B-energy operator and cross-power spectral density
http://hdl.handle.net/10985/8999
Psi_B-energy operator and cross-power spectral density
CHONAVEL, Thierry; CEXUS, Jean-Christophe; BOUDRAA, Abdel-Ouahab
In this paper we consider the hermitian extension of the cross-Psi_B-energy operator that we will denote by Psi_H. In addition, cross energy terms are formalized through multivariate signals representation. We investigate the connection between the interaction energy function of Psi_H and the cross-power spectral density (CPSD)of two complex valued signals. In particular, this link permits to use this operator for estimating the CPSD. We illustrate the interest of Psi_H as a similarity between a pair of signals in frequency domain on synthetic and real data.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/89992014-01-01T00:00:00ZCHONAVEL, ThierryCEXUS, Jean-ChristopheBOUDRAA, Abdel-OuahabIn this paper we consider the hermitian extension of the cross-Psi_B-energy operator that we will denote by Psi_H. In addition, cross energy terms are formalized through multivariate signals representation. We investigate the connection between the interaction energy function of Psi_H and the cross-power spectral density (CPSD)of two complex valued signals. In particular, this link permits to use this operator for estimating the CPSD. We illustrate the interest of Psi_H as a similarity between a pair of signals in frequency domain on synthetic and real data.Analysis of multicomponent LFM signals by Teager-Huang-Hough Transform
http://hdl.handle.net/10985/8919
Analysis of multicomponent LFM signals by Teager-Huang-Hough Transform; Analyse des signaux multicomposante à modulation de fréquence linéaire par la transformation de Teager-Huang-Hough
BOUCHIKHI, Abdelkhalek; CEXUS, Jean-Christophe; CHONAVEL, Thierry; BOUDRAA, Abdel-Ouahab
A novel detection approach of linear FM (LFM) signals, with single or multiple components, in the time-frequency plane of Teager-Huang (TH) transform is presented. The detection scheme that combines TH transform and Hough transform is referred to as Teager-Huang-Hough (THH) transform. The input signal is mapped into the time-frequency plane by using TH transform followed by the application of Hough transform to recognize time-frequency components. LFM components are detected and their parameters are estimated from peaks and their locations in the Hough space. Advantages of THH transform over Hough transform of Wigner-Ville distribution (WVD) are: 1) cross-terms free detection and estimation, and 2) good time and frequency resolutions. No assumptions are made about the number of components of the LFM signals and their models. THH transform is illustrated on multicomponent LFM signals in free and noisy environments and the results compared with WVD-Hough and pseudo-WVD-Hough transforms.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/89192014-01-01T00:00:00ZBOUCHIKHI, AbdelkhalekCEXUS, Jean-ChristopheCHONAVEL, ThierryBOUDRAA, Abdel-OuahabA novel detection approach of linear FM (LFM) signals, with single or multiple components, in the time-frequency plane of Teager-Huang (TH) transform is presented. The detection scheme that combines TH transform and Hough transform is referred to as Teager-Huang-Hough (THH) transform. The input signal is mapped into the time-frequency plane by using TH transform followed by the application of Hough transform to recognize time-frequency components. LFM components are detected and their parameters are estimated from peaks and their locations in the Hough space. Advantages of THH transform over Hough transform of Wigner-Ville distribution (WVD) are: 1) cross-terms free detection and estimation, and 2) good time and frequency resolutions. No assumptions are made about the number of components of the LFM signals and their models. THH transform is illustrated on multicomponent LFM signals in free and noisy environments and the results compared with WVD-Hough and pseudo-WVD-Hough transforms.A New class of multi-dimensional Teager Kaiser and higher order operators based on directional derivatives
http://hdl.handle.net/10985/8857
A New class of multi-dimensional Teager Kaiser and higher order operators based on directional derivatives; Une nouvelle classe d'opérateurs de Teager-Kaiser multidimensionnels basée sur les dérivées directionnelles d'ordre supérieur
SALZENSTEIN, Fabien; CHONAVEL, Thierry; BOUDRAA, Abdel-Ouahab
This work aims at introducing some energy operators linked to Teager-Kaiser energy operator and its associated higher order versions and expand them to multidimensional signals. These operators are very useful for analyzing oscillatory signals with time-varying amplitude and frequency (AM-FM). We prove that gradient tensors combined with Kronecker powers allow to express these operators by directional derivatives along any n-D vector. In particular, we show that the construction of a large class of non linear operators for AM-FM multidimensional signal demodulation is possible. Also, a new scalar function using the directional derivative along a vector giving the ”sign” of the frequency components is introduced. An application of this model to local n-D AM-FM signal is presented and related demodulation error rates estimates. To show the effectiveness and the robustness of our method in term of envelope and frequency components extraction, results obtained on synthetic and real data are compared to multi-dimensional energy separation algorithm and to our recently introduced n-D operator.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/88572013-01-01T00:00:00ZSALZENSTEIN, FabienCHONAVEL, ThierryBOUDRAA, Abdel-OuahabThis work aims at introducing some energy operators linked to Teager-Kaiser energy operator and its associated higher order versions and expand them to multidimensional signals. These operators are very useful for analyzing oscillatory signals with time-varying amplitude and frequency (AM-FM). We prove that gradient tensors combined with Kronecker powers allow to express these operators by directional derivatives along any n-D vector. In particular, we show that the construction of a large class of non linear operators for AM-FM multidimensional signal demodulation is possible. Also, a new scalar function using the directional derivative along a vector giving the ”sign” of the frequency components is introduced. An application of this model to local n-D AM-FM signal is presented and related demodulation error rates estimates. To show the effectiveness and the robustness of our method in term of envelope and frequency components extraction, results obtained on synthetic and real data are compared to multi-dimensional energy separation algorithm and to our recently introduced n-D operator.