ISEN Brest

Brest, France

ISEN Brest

Brest, France
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Leonard I.,ISEN Brest | Alfalou A.,ISEN Brest | Alam M.S.,University of South Alabama | Arnold-Bos A.,Thales Alenia
Optical Engineering | Year: 2012

An optimized technique, based on the fringe-adjusted joint transform correlator architecture, is proposed and validated for rotation invariant recognition and tracking of a target in an unknown input scene. To enhance the robustness of the proposed technique, we used a three-step optimization. First, we utilized the fringe-adjusted filter (HFAF) in the Fourier plane, then we added nonlinear processing in the Fourier plane, and, finally, we used a new decision criterion in the correlation plane by considering the correlation peak energy and the highest peaks outside the desired correlation peak. Several tests were conducted to reduce the number of reference images needed for fast tracking, while ensuring robust discrimination and efficient tracking of the desired target. Test results, obtained using the pointing head pose image database, confirm robust performance of the proposed method for face recognition and tracking applications. Thereafter, we also tested the proposed technique for a challenging application such as underwater mine detection and excellent results were obtained. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Alfalou A.,ISEN Brest | Brosseau C.,University of Western Brittany | Abdallah N.,ISEN Brest | Jridi M.,ISEN Brest
Optics Express | Year: 2013

We introduce a double optimization procedure for spectrally multiplexing multiple images. This technique is adapted from a recently proposed optical setup implementing the discrete cosine transformation (DCT). The new analysis technique is a combination of spectral fusion based on the properties of DCT, specific spectral filtering, and quantization of the remaining encoded frequencies using an optimal number of bits. Spectrally multiplexing multiple images defines a first level of encryption. A second level of encryption based on a real key image is used to reinforce encryption. A set of numerical simulations and a comparison with the well known JPEG (Joint Photographic Experts Group) image compression standard have been carried out to demonstrate the improved performances of this method. The focus here will differ from the method of simultaneous fusion, compression, and encryption of multiple images (SFCE) [Opt. Express 19, 24023 (2011)] in the following ways. Firstly, we shall be concerned with optimizing the compression rate by adapting the size of the spectral block to each target image and decreasing the number of bits required to encode each block. This size adaptation is achieved by means of the root-mean-square (RMS) time-frequency criterion. We found that this size adaptation provides a good tradeoff between bandwidth of spectral plane and number of reconstructed output images. Secondly, the encryption rate is improved by using a real biometric key and randomly changing the rotation angle of each block before spectral fusion. By using a real-valued key image we have been able to increase the compression rate of 50% over the original SFCE method. We provide numerical examples of the effects for size, rotation, and shifting of DCT-blocks which play noteworthy roles in the optimization of the bandwidth of the spectral plane. Inspection of the results for different types of attack demonstrates the robustness of our procedure. © 2013 Optical Society of America.

Alfalou A.,ISEN Brest | Brosseau C.,University of Western Brittany | Alam M.S.,University of South Alabama
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The purpose of this paper is to test correlation methods for pattern recognition applications. A broad overview of the main correlation architectures is first given. Many correlation data are compared with those obtained from standard pattern recognition methods. We used our simulations to predict improved decisional performance from correlation methods. More specifically, we are focused on the POF filter and composite filter family. We present an optimized composite correlation filter, called asymmetric segmented phase-only filter (ASPOF) for mobile target recognition applications. The main objective is to find a compromise between the number of references to be merged in the correlation filter and the time needed for making a decision. We suggest an all-numerical implementation of a VanderLugt (VLC) type composite filter. The aim of this all-numerical implementation is to take advantage of the benefits of the correlation methods and make the correlator easily reconfigurable for various scenarios. The use of numerical implementation of the optical Fourier transform improves the decisional performance of the correlator. Further, it renders the correlator less sensitive to the saturation phenomenon caused by the increased number of references used for fabricating the composite filter. Different tests are presented making use of the peak-to-correlation energy criterion and ROC curves. These tests confirm the validity ofour technique. Elderly fall detection and underwater mine detection are two applications which are considered for illustrating the benefits of our approach. The present work is motivated by the need for detailed discussions of the choice of the correlation architecture for these specific applications, pre-processing in the input plane and post processing in the output plane techniques for such analysis. © 2013 SPIE.

Leonard I.,ISEN Brest | Alfalou A.,ISEN Brest | Alam M.S.,University of South Alabama
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

In this paper, we propose a new technique for rotation invariant recognition and tracking of the face of a target person in a given scene. We propose an optimized method for face tracking based on the Fringe-adjusted JTC architecture. To validate our approach, we used the PHPID data base containing1 faces with various in-plane rotations. To enhance the robustness of the proposed method, we used a three-step optimization technique by: (1) utilizing the fringe-adjusted filter (HFAF) in the Fourier plane, (2) adding nonlinearity in the Fourier plane after applying the HFAF filter, and (3) using a new decision criterion in the correlation plane by considering the correlation peak energy and five largest peaks outside the highest correlation peak. Several tests were made to reduce the number of reference images needed for fast tracking while ensuring robust discrimination and efficient of the desired target. © 2011 SPIE.

Alfalou A.,ISEN Brest | Brosseau C.,European University of Brittany | Katz P.,ISEN Brest | Alam M.S.,University of South Alabama
Optics Letters | Year: 2012

We consider a new approach for enhancing the discrimination performance of the VanderLugt correlator. Instead of trying to optimize the correlation filter, or propose a new decision correlation peak detection criterion, we propose herein to denoise the correlation plane before applying the peak-to-correlation energy (PCE) criterion. For that purpose, we use a linear functional model to express a given correlation plane as a linear combination of the correlation peak, noise, and residual components. The correlation peak is modeled using an orthonormalized function and the singular value decomposition method. A set of training correlation planes is then selected to create the correlation noise components. Finally, an optimized correlation plane is reconstructed while discarding the noise components. Independently of the filter correlation used, this technique denoises the correlation plane by lowering the correlation noise magnitude in case of true correlation and decreases the false alarm rate when the target image does not belong to the desired class. Test results are presented, using a composite filter and a face recognition application, to verify the effectiveness of the proposed technique. © 2012 Optical Society of America.

Alfalou A.,ISEN Brest | Brosseau C.,European University of Brittany | Abdallah N.,ISEN Brest | Jridi M.,ISEN Brest
Optics Express | Year: 2011

We report a new spectral multiple image fusion analysis based on the discrete cosine transform (DCT) and a specific spectral filtering method. In order to decrease the size of the multiplexed file, we suggest a procedure of compression which is based on an adapted spectral quantization. Each frequency is encoded with an optimized number of bits according its importance and its position in the DC domain. This fusion and compression scheme constitutes a first level of encryption. A supplementary level of encryption is realized by making use of biometric information. We consider several implementations of this analysis by experimenting with sequences of gray scale images. To quantify the performance of our method we calculate the MSE (mean squared error) and the PSNR (peak signal to noise ratio). Our results consistently improve performances compared to the wellknown JPEG image compression standard and provide a viable solution for simultaneous compression and encryption of multiple images. © 2011 Optical Society of America.

Napoleon T.,ISEN Brest | AlFalou A.,ISEN Brest
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

The face recognition tasks can be divided into two categories: verification (i.e. compare two images in order to know if they represent the same person) and identification (i.e. find the identity of a person into the database). Several powerful face recognition methods exist, in literature, for controlled environments: constrained illumination, frontal pose, neutral expression... However, there are few reliable methods for the uncontrolled case. Optical correlation has shown its interest through relevant architectures for controlled and uncontrolled environments. Based on this architecture, we propose a novel method for verification and identification tasks under illumination variation conditions. More specifically, we optimize the performances of a correlation method against illumination changes by using and adapting the Local Binary Patterns (LBP) description. This later is widely used in the literature to describe the texture of an image using 8 bits words. For both, target image and reference image, we begin by using a specific-Gaussian function as first step of LBP-VLC correlator. This function filters the considered image with a band-pass filter in order to extract the edges. Then we applied the adapted LBP-VLC method. To validate our new approach, we used a simple POF filter (others correlation filters can be used). The simulations are done using the YaleB and YaleB Extended databases that contain respectively 10 and 38 identities with 64 illuminations. The results obtained reach more than 94% and 92% for the verification and 93% and 90% for the identification case. These results show the good performances of our approach of LBP-correlation methods against illumination changes. © 2014 Copyright SPIE.

Bouvet P.-J.,ISEN Brest | Helard M.,INSA Rennes
Annales des Telecommunications/Annals of Telecommunications | Year: 2014

In this paper, we deal with the design of a full-rate space-time block coding (STBC) scheme optimized for linear iterative decoding over fast fading multiple-input multiple-output (MIMO) channel. A general and simple coding scheme called diagonal threaded space-time (DTST) code is presented for an arbitrary number of transmit and receive antennas. Theoretical analysis shows that DTST code associated with linear iterative decoding tends towards full diversity performance while providing maximum MIMO multiplexing gain. Simulation results confirm the ability of DTST to outperform the state-of-the-art STBC and conventional spatial data multiplexing schemes under iterative processing. © 2013 Institut Mines-Télécom and Springer-Verlag France.

Rezgui W.,University of Batna | Mouss L.-H.,University of Batna | Mouss K.N.,University of Batna | Mouss M.D.,University of Batna | And 2 more authors.
International Review on Modelling and Simulations | Year: 2014

In this paper, we presented a new methodology for the mathematical modeling of the photovoltaic generator's characteristics based on known electrical laws. This proposed new methodology in this work consists of a three new algorithms, each one presents the characteristic of the cell, group of cells, module, string and generator, when one or more of its components: cells, bypass diodes and blocking diodes subjected to these types of defaults: reversed polarity, open circuit, short circuit or impedance. The three new algorithms obtained can facilitate the prediction for the prognosis or the detection for the diagnosis of these photovoltaic generator's defaults. © 2014 Praise Worthy Prize S.r.l. - All rights reserved.

Alfalou A.,ISEN Brest | Ben-Haj-Yahia N.,ISEN Brest | Elbouz M.,ISEN Brest | Alam M.S.,University of South Alabama
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

For face recognition applications, it is necessary to have a robust discrimination system. In this paper, a new method for denoising the correlation plane and removing the zero-order term associated with alternate joint transform correlator (JTC) architectures such as the nonlinear JTC (NJTC) and nonlinear non-zero-order JTC (NNJTC) is proposed. The proposed technique is called nonlinear denoised JTC (NDJTC) which incorporates the attractive features of NJTC and NNJTC to ensure good compromise between discrimination and robustness while denoising the correlation plane. To investigate the performance of the proposed technique, various tests are performed using the PHPID face database and the results demonstrate excellent behavior of the proposed NDJTC. In this technique, the zero-order term and the impact of noise in the correlation plane were removed leading to increased robustness and discrimination ability of the NJTC. To confirm these results, different comparisons were performed using a NJTC and a NNJTC. Finally, a study using different levels of nonlinearity was conducted to find the best compromise between robustness and discrimination ability of the proposed method. © 2012 SPIE.

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