The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Julien Gaulmin - One of the best experts on this subject based on the ideXlab platform.

  • EUSIPCO - Video analysis and synthesis based on a retinal-inspired frame
    2015 23rd European Signal Processing Conference (EUSIPCO), 2015
    Co-Authors: Effrosyni Doutsi, Lionel Fillatre, Marc Antonini, Julien Gaulmin
    Abstract:

    This paper introduces a novel retinal-inspired filter which is applied on video streams. We mathematically prove that under specific assumptions the spatiotemporal Convolution turns into a Spatial Convolution with a short lifespan temporal kernel. As a consequence, the filter is applied on each image of the video stream separately. We analyze how each image is decomposed into a group of subbands, each one of which approximates the image providing different kind of information. Afterwords, we propose an algorithm to reconstruct each image by exploiting the group of subbands. Finally, we defend our mathematical proofs by providing numerical simulations which show the relevance of our study.

  • Video analysis and synthesis based on a retinal-inspired frame
    2015 23rd European Signal Processing Conference (EUSIPCO), 2015
    Co-Authors: Effrosyni Doutsi, Lionel Fillatre, Marc Antonini, Julien Gaulmin
    Abstract:

    This paper introduces a novel retinal-inspired filter which is applied on video streams. We mathematically prove that under specific assumptions the spatiotemporal Convolution turns into a Spatial Convolution with a short lifespan temporal kernel. As a consequence, the filter is applied on each image of the video stream separately. We analyze how each image is decomposed into a group of subbands, each one of which approximates the image providing different kind of information. Afterwords, we propose an algorithm to reconstruct each image by exploiting the group of subbands. Finally, we defend our mathematical proofs by providing numerical simulations which show the relevance of our study.

A. Abergel - One of the best experts on this subject based on the ideXlab platform.

  • EUSIPCO - Restoration from multispectral blurred data with non-stationary instrument response
    2017 25th European Signal Processing Conference (EUSIPCO), 2017
    Co-Authors: M. A. Hadj-youcef, F. Orieux, A. Fraysse, A. Abergel
    Abstract:

    In this paper we propose an approach of image restoration from multispectral data provided by an imaging system. We specifically address two topics: (i) Development of a multi-wavelength direct model for non-stationary instrument response that includes a Spatial Convolution and a spectral integration, (ii) Implementation of multispectral image restoration using a regularized least-square, based on a quadratic criterion and minimized by a gradient algorithm. We test our approach on simulated data of the Mid-InfraRed Instrument IMager (MIRIM) of the James Webb Space Telescope (JWST). Our method shows a clear increase of Spatial resolution compare to conventional methods.

  • Restoration from multispectral blurred data with non-stationary instrument response
    2017 25th European Signal Processing Conference (EUSIPCO), 2017
    Co-Authors: M. A. Hadj-youcef, F. Orieux, A. Fraysse, A. Abergel
    Abstract:

    In this paper we propose an approach of image restoration from multispectral data provided by an imaging system. We specifically address two topics: (i) Development of a multi-wavelength direct model for non-stationary instrument response that includes a Spatial Convolution and a spectral integration, (ii) Implementation of multispectral image restoration using a regularized least-square, based on a quadratic criterion and minimized by a gradient algorithm. We test our approach on simulated data of the Mid-InfraRed Instrument IMager (MIRIM) of the James Webb Space Telescope (JWST). Our method shows a clear increase of Spatial resolution compare to conventional methods.

Effrosyni Doutsi - One of the best experts on this subject based on the ideXlab platform.

  • EUSIPCO - Video analysis and synthesis based on a retinal-inspired frame
    2015 23rd European Signal Processing Conference (EUSIPCO), 2015
    Co-Authors: Effrosyni Doutsi, Lionel Fillatre, Marc Antonini, Julien Gaulmin
    Abstract:

    This paper introduces a novel retinal-inspired filter which is applied on video streams. We mathematically prove that under specific assumptions the spatiotemporal Convolution turns into a Spatial Convolution with a short lifespan temporal kernel. As a consequence, the filter is applied on each image of the video stream separately. We analyze how each image is decomposed into a group of subbands, each one of which approximates the image providing different kind of information. Afterwords, we propose an algorithm to reconstruct each image by exploiting the group of subbands. Finally, we defend our mathematical proofs by providing numerical simulations which show the relevance of our study.

  • Video analysis and synthesis based on a retinal-inspired frame
    2015 23rd European Signal Processing Conference (EUSIPCO), 2015
    Co-Authors: Effrosyni Doutsi, Lionel Fillatre, Marc Antonini, Julien Gaulmin
    Abstract:

    This paper introduces a novel retinal-inspired filter which is applied on video streams. We mathematically prove that under specific assumptions the spatiotemporal Convolution turns into a Spatial Convolution with a short lifespan temporal kernel. As a consequence, the filter is applied on each image of the video stream separately. We analyze how each image is decomposed into a group of subbands, each one of which approximates the image providing different kind of information. Afterwords, we propose an algorithm to reconstruct each image by exploiting the group of subbands. Finally, we defend our mathematical proofs by providing numerical simulations which show the relevance of our study.

P.m. Van Den Berg - One of the best experts on this subject based on the ideXlab platform.

  • A Weak Form of the Conjugate Gradient FFT Method for Two-Dimensional Elastodynamics
    Journal of Computational Physics, 2000
    Co-Authors: George Pelekanos, Ralph E. Kleinman, P.m. Van Den Berg
    Abstract:

    The problem of two-dimensional scattering of elastic waves by an elastic inclusion can be formulated in terms of a domain integral equation, in which the grad-div operator acts on a vector potential. The vector potential is the Spatial Convolution of a Green's function with the product of the density and the displacement over the domain of interest. A weak form of the integral equation for the unknown displacement is obtained by testing it with rooftop functions. This method shows excellent numerical performance.

  • The three dimensional weak form of the conjugate gradient FFT method for solving scattering problems
    IEEE Transactions on Microwave Theory and Techniques, 1992
    Co-Authors: P. Zwamborn, P.m. Van Den Berg
    Abstract:

    The problem of electromagnetic scattering by a three-dimensional dielectric object can be formulated in terms of a hypersingular integral equation, in which a grad-div operator acts on a vector potential. The vector potential is a Spatial Convolution of the free space Green's function and the contrast source over the domain of interest. A weak form of the integral equation for the relevant unknown quantity is obtained by testing it with appropriate testing functions. The vector potential is then expanded in a sequence of the appropriate expansion functions and the grad-div operator is integrated analytically over the scattering object domain only. A weak form of the singular Green's function has been used by introducing its spherical mean. As a result, the Spatial Convolution can be carried out numerically using a trapezoidal integration rule. This method shows excellent numerical performance.

  • An improved conjugate gradient FFT method for 2-D TE scattering problems
    Antennas and Propagation Society Symposium 1991 Digest, 1991
    Co-Authors: A.p.m. Zwamborn, P.m. Van Den Berg
    Abstract:

    It is pointed out that the problem of two-dimensional scattering of a transverse electric (TE) polarized wave by a dielectric object can be formulated in terms of a hypersingular integral equation, in which a grad-div operator acts on a vector potential. The vector potential is a Spatial Convolution of the free-space Green's function and the contrast source over the domain of interest. A weak form of the integral equation for the unknown electric flux density is obtained by testing it with roof-top functions. As the next step, the vector potential is expanded in a sequence of the roof-top functions and the grad-div operator is integrated analytically over the dielectric object domain only. Numerical results are presented for a lossy dielectric coaxially layered cylinder. The method considered shows excellent numerical performance.

  • A weak form of the conjugate gradient FFT method for two-dimensional TE scattering problems
    IEEE Transactions on Microwave Theory and Techniques, 1991
    Co-Authors: P. Zwamborn, P.m. Van Den Berg
    Abstract:

    The problem of two-dimensional scattering of a transversal electric polarized wave, by a dielectric object is formulated in terms of a hypersingular integral equation, in which a grad-div operator acts on a vector potential. The vector potential is a Spatial Convolution of the free-space Green's function and the contrast source over the domain of interest. A weak form of the integral equation for the unknown electric flux density is obtained by testing it with rooftop functions. The vector potential is expanded in a sequence of the rooftop functions and the grad-div operator is integrated analytically over the dielectric object domain only. The method shows excellent numerical performance.

M. A. Hadj-youcef - One of the best experts on this subject based on the ideXlab platform.

  • EUSIPCO - Restoration from multispectral blurred data with non-stationary instrument response
    2017 25th European Signal Processing Conference (EUSIPCO), 2017
    Co-Authors: M. A. Hadj-youcef, F. Orieux, A. Fraysse, A. Abergel
    Abstract:

    In this paper we propose an approach of image restoration from multispectral data provided by an imaging system. We specifically address two topics: (i) Development of a multi-wavelength direct model for non-stationary instrument response that includes a Spatial Convolution and a spectral integration, (ii) Implementation of multispectral image restoration using a regularized least-square, based on a quadratic criterion and minimized by a gradient algorithm. We test our approach on simulated data of the Mid-InfraRed Instrument IMager (MIRIM) of the James Webb Space Telescope (JWST). Our method shows a clear increase of Spatial resolution compare to conventional methods.

  • Restoration from multispectral blurred data with non-stationary instrument response
    2017 25th European Signal Processing Conference (EUSIPCO), 2017
    Co-Authors: M. A. Hadj-youcef, F. Orieux, A. Fraysse, A. Abergel
    Abstract:

    In this paper we propose an approach of image restoration from multispectral data provided by an imaging system. We specifically address two topics: (i) Development of a multi-wavelength direct model for non-stationary instrument response that includes a Spatial Convolution and a spectral integration, (ii) Implementation of multispectral image restoration using a regularized least-square, based on a quadratic criterion and minimized by a gradient algorithm. We test our approach on simulated data of the Mid-InfraRed Instrument IMager (MIRIM) of the James Webb Space Telescope (JWST). Our method shows a clear increase of Spatial resolution compare to conventional methods.