Ecole Navale

Brest, France

Ecole Navale

Brest, France
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Khaldi K.,National Engineering School of Tunis | Boudraa A.-O.,Ecole Navale
IEEE Transactions on Audio, Speech and Language Processing | Year: 2013

In this paper a new adaptive audio watermarking algorithm based on Empirical Mode Decomposition (EMD) is introduced. The audio signal is divided into frames and each one is decomposed adaptively, by EMD, into intrinsic oscillatory components called Intrinsic Mode Functions (IMFs). The watermark and the synchronization codes are embedded into the extrema of the last IMF, a low frequency mode stable under different attacks and preserving audio perceptual quality of the host signal. The data embedding rate of the proposed algorithm is 46.9-50.3 b/s. Relying on exhaustive simulations, we show the robustness of the hidden watermark for additive noise, MP3 compression, re-quantization, filtering, cropping and resampling. The comparison analysis shows that our method has better performance than watermarking schemes reported recently. © 2006-2012 IEEE.

Drira A.,Ecole Navale | Guillon L.,Ecole Navale | Boudraa A.-O.,Ecole Navale
Journal of the Acoustical Society of America | Year: 2014

This letter presents an improvement of the image source method for geoacoustic inversion. The algorithm is based on the Teager-Kaiser energy operator which amplifies the discontinuities in signals while the soft transitions are reduced. This property is exploited for accurate detection of time arrivals and thus for location of the image sources. The effectiveness of the method is shown on both synthetic and real data and the inversion results are, overall, in good agreement with ground truth and other inversion results with a significant reduction of computation time. © 2014 Acoustical Society of America.

Khaldi K.,Ecole Navale | Boudraa A.O.,Ecole Navale
Electronics Letters | Year: 2012

A new signals coding framework based on empirical mode decomposition (EMD) is introduced. EMD breaks down any signal into a reduced number of oscillating components called intrinsic modes functions (IMFs). Based on IMF properties, different coding strategies are presented. No assumptions concerning the linearity or the stationarity are made about the signal to be coded. Results obtained on ECG signals are presented and compared to those of wavelet coding. © 2012 The Institution of Engineering and Technology.

Komaty A.,Ecole Navale | Boudraa A.-O.,Ecole Navale | Augier B.,Ecole Navale | Dare-Emzivat D.,Ecole Navale
IEEE Transactions on Instrumentation and Measurement | Year: 2014

This paper introduces a new signal-filtering, which combines the empirical mode decomposition (EMD) and a similarity measure. A noisy signal is adaptively broken down into oscillatory components called intrinsic mode functions by EMD followed by an estimation of the probability density function (pdf) of each extracted mode. The key idea of this paper is to make use of partial reconstruction, the relevant modes being selected on the basis of a striking similarity between the pdf of the input signal and that of each mode. Different similarity measures are investigated and compared. The obtained results, on simulated and real signals, show the effectiveness of the pdf-based filtering strategy for removing both white Gaussian and colored noises and demonstrate its superior performance over partial reconstruction approaches reported in the literature. © 1963-2012 IEEE.

Boudraa A.-O.,Ecole Navale
Electronics Letters | Year: 2011

The ΨB energy operator is an extension of the cross-Teager-Kaiser energy operator which is a nonlinear energy tracking operator to deal with complex signals and its usefulness for non-stationary signals analysis has been demonstrated. Two new properties of ΨB are established. The first property is the link between ΨB and the dynamic signal which is a generalisation of the instantaneous frequency (IF). The second property obtained for frequency modulated (FM) signals is a simple way to estimate the IF. These properties confirm the interest of the ΨB operator to track the non-stationarity of a signal. Results of IF estimation in a noisy environment of a nonlinear FM signal are presented and comparison to the Wigner-Ville distribution and the Hilbert transform-based method is provided. © 2011 The Institution of Engineering and Technology.

Salzenstein F.,ICube | Montgomery P.,ICube | Boudraa A.O.,Ecole Navale
Optics Express | Year: 2014

In this work, a new method for surface extraction in white light scanning interferometry (WLSI) is introduced. The proposed extraction scheme is based on the Teager-Kaiser energy operator and its extended versions. This non-linear class of operators is helpful to extract the local instantaneous envelope and frequency of any narrow band AM-FM signal. Namely, the combination of the envelope and frequency information, allows effective surface extraction by an iterative re-estimation of the phase in association with a new correlation technique, based on a recent TK crossenergy operator. Through the experiments, it is shown that the proposed method produces substantially effective results in term of surface extraction compared to the peak fringe scanning technique, the five step phase shifting algorithm and the continuous wavelet transform based method. In addition, the results obtained show the robustness of the proposed method to noise and to the fluctuations of the carrier frequency. © 2014 Optical Society of America.

Khaldi K.,National Engineering School of Tunis | Boudraa A.-O.,Ecole Navale | Komaty A.,Ecole Navale
Journal of the Acoustical Society of America | Year: 2014

In this paper a speech denoising strategy based on time adaptive thresholding of intrinsic modes functions (IMFs) of the signal, extracted by empirical mode decomposition (EMD), is introduced. The denoised signal is reconstructed by the superposition of its adaptive thresholded IMFs. Adaptive thresholds are estimated using the Teager-Kaiser energy operator (TKEO) of signal IMFs. More precisely, TKEO identifies the type of frame by expanding differences between speech and non-speech frames in each IMF. Based on the EMD, the proposed speech denoising scheme is a fully data-driven approach. The method is tested on speech signals with different noise levels and the results are compared to EMD-shrinkage and wavelet transform (WT) coupled with TKEO. Speech enhancement performance is evaluated using output signal to noise ratio (SNR) and perceptual evaluation of speech quality (PESQ) measure. Based on the analyzed speech signals, the proposed enhancement scheme performs better than WT-TKEO and EMD-shrinkage approaches in terms of output SNR and PESQ. The noise is greatly reduced using time-adaptive thresholding than universal thresholding. The study is limited to signals corrupted by additive white Gaussian noise. © 2014 Acoustical Society of America.

Flores Cortez D.,Federal University of Santa Catarina | Waltrich G.,Federal University of Santa Catarina | Fraigneaud J.,Ecole Navale | Miranda H.,Ecole Navale | Barbi I.,Federal University of Santa Catarina
IEEE Transactions on Industrial Electronics | Year: 2015

Automotive embedded electronic systems have been increasing in power and complexity and, therefore, more advanced power electronic converters are necessary in these vehicles. Several dual-voltage (42 V/14 V) bidirectional converter architectures have been proposed for automotive systems in recent years. However, most of them have low efficiency or are based in series and parallel configurations with large number of semiconductors and magnetics devices. Therefore, in this paper, we propose a bidirectional high-efficiency converter with lower number of components. This converter was created by merging a switched-capacitor converter and a conventional bidirectional converter, resulting in a hybrid topology. The voltage across the semiconductors of the proposed converter is equal to half of the highest voltage source value. Furthermore, the topology is composed of only one inductor to control the power flow between the two voltage sources. To verify all the mentioned features, a prototype was implemented experimentally, reaching a maximum efficiency of 97.5%. © 1982-2012 IEEE.

Bouchikhi A.,Ecole Navale | Boudraa A.-O.,Ecole Navale | Cexus J.-C.,ENSTA Bretagne | Chonavel T.,Telecom Bretagne
IEEE Transactions on Aerospace and Electronic Systems | Year: 2014

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. © 2014 IEEE.

Komaty A.,Ecole Navale | Boudraa A.,Ecole Navale | Dare D.,Ecole Navale
2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012 | Year: 2012

This paper introduces a new signal-filtering method, which combines the empirical mode decomposition (EMD) and the Hausdorff distance (HD). A noisy signal is adaptively broken down into oscillatory components called intrinsic mode functions (IMFs) by EMD followed by an estimation of the probability density function (pdf) of each extracted mode. The filtered signal is obtained by performing a partial reconstruction using a selected set of empirical modes (termed relevant modes). The article focuses on an intuitive geometrical approach to identify the relevant modes based on the HD between the pdf of the noisy signal and that of each mode. Obtained results of the new filtering are compared to those of the EMD-CMSE (Consecutive Minimum Square Error) [1], the White Noise characteristics approach EMD-WN [2] and the Selection Criterion approach EMD-SC [3]. Dn different signals with varying signal-to-noise ratio values are used to validate the obtained results. The study is limited to signals corrupted by additive white Gaussian noise. © 2012 IEEE.

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