Search Results for author: Nelly Pustelnik

Found 16 papers, 4 papers with code

Equivariant plug-and-play image reconstruction

no code implementations4 Dec 2023 Matthieu Terris, Thomas Moreau, Nelly Pustelnik, Julian Tachella

Plug-and-play algorithms constitute a popular framework for solving inverse imaging problems that rely on the implicit definition of an image prior via a denoiser.

Denoising Image Reconstruction

PNN: From proximal algorithms to robust unfolded image denoising networks and Plug-and-Play methods

no code implementations6 Aug 2023 Hoang Trieu Vy Le, Audrey Repetti, Nelly Pustelnik

In particular, proximal neural networks (PNNs) have been introduced, obtained by unrolling a proximal algorithm as for finding a MAP estimate, but over a fixed number of iterations, with learned linear operators and parameters.

Deblurring Image Deblurring +2

Covid19 Reproduction Number: Credibility Intervals by Blockwise Proximal Monte Carlo Samplers

1 code implementation17 Mar 2022 Gersende Fort, Barbara Pascal, Patrice Abry, Nelly Pustelnik

The originality of the devised algorithms stems from combining a Langevin Monte Carlo sampling scheme with Proximal operators.

Alternative design of DeepPDNet in the context of image restoration

no code implementations20 Feb 2022 Mingyuan Jiu, Nelly Pustelnik

Preliminary experiments illustrate the good behavior of such a deep primal-dual network in the context of image restoration on BSD68 database.

Image Restoration

Temporal evolution of the Covid19 pandemic reproduction number: Estimations from proximal optimization to Monte Carlo sampling

no code implementations11 Feb 2022 Patrice Abry, Gersende Fort, Barbara Pascal, Nelly Pustelnik

Yet, the assessment of the pandemic intensity within the pandemic period remains a challenging task because of the limited quality of data made available by public health authorities (missing data, outliers and pseudoseasonalities, notably), that calls for cumbersome and ad-hoc preprocessing (denoising) prior to estimation.

Denoising

Hyperparameter selection for Discrete Mumford-Shah

1 code implementation28 Sep 2021 Charles-Gérard Lucas, Barbara Pascal, Nelly Pustelnik, Patrice Abry

This work focuses on a parameter-free joint piecewise smooth image denoising and contour detection.

Contour Detection Image Denoising +1

Nonsmooth convex optimization to estimate the Covid-19 reproduction number space-time evolution with robustness against low quality data

no code implementations20 Sep 2021 Barbara Pascal, Patrice Abry, Nelly Pustelnik, Stéphane G. Roux, Rémi Gribonval, Patrick Flandrin

The present work aims to overcome these limitations by carefully crafting a functional permitting to estimate jointly, in a single step, the reproduction number and outliers defined to model low quality data.

Epidemiology

A deep primal-dual proximal network for image restoration

no code implementations2 Jul 2020 Mingyuan Jiu, Nelly Pustelnik

In this work, we design a deep network, named DeepPDNet, built from primal-dual proximal iterations associated with the minimization of a standard penalized likelihood with an analysis prior, allowing us to take advantage of both worlds.

Image Classification Image Restoration +1

Automated data-driven selection of the hyperparameters for Total-Variation based texture segmentation

no code implementations20 Apr 2020 Barbara Pascal, Samuel Vaiter, Nelly Pustelnik, Patrice Abry

This work extends the Stein's Unbiased GrAdient estimator of the Risk of Deledalle et al. to the case of correlated Gaussian noise, deriving a general automatic tuning of regularization parameters.

Solving NMF with smoothness and sparsity constraints using PALM

1 code implementation31 Oct 2019 Raimon Fabregat, Nelly Pustelnik, Paulo Gonçalves, Pierre Borgnat

Non-negative matrix factorization is a problem of dimensionality reduction and source separation of data that has been widely used in many fields since it was studied in depth in 1999 by Lee and Seung, including in compression of data, document clustering, processing of audio spectrograms and astronomy.

Astronomy Clustering +1

Sparse hierarchical interaction learning with epigraphical projection

1 code implementation22 May 2017 Mingyuan Jiu, Nelly Pustelnik, Stefan Janaqi, Mériam Chebre, Lin Qi, Philippe Ricoux

This work focuses on learning optimization problems with quadratical interactions between variables, which go beyond the additive models of traditional linear learning.

Additive models

Bayesian selection for the l2-Potts model regularization parameter: 1D piecewise constant signal denoising

no code implementations27 Aug 2016 Jordan Frecon, Nelly Pustelnik, Nicolas Dobigeon, Herwig Wendt, Patrice Abry

Piecewise constant denoising can be solved either by deterministic optimization approaches, based on the Potts model, or by stochastic Bayesian procedures.

Denoising

On-the-fly Approximation of Multivariate Total Variation Minimization

no code implementations22 Apr 2015 Jordan Frecon, Nelly Pustelnik, Patrice Abry, Laurent Condat

In the context of change-point detection, addressed by Total Variation minimization strategies, an efficient on-the-fly algorithm has been designed leading to exact solutions for univariate data.

Change Point Detection

A Proximal Approach for Sparse Multiclass SVM

no code implementations15 Jan 2015 G. Chierchia, Nelly Pustelnik, Jean-Christophe Pesquet, B. Pesquet-Popescu

In this paper, we propose a convex optimization approach for efficiently and exactly solving the multiclass SVM learning problem involving a sparse regularization and the multiclass hinge loss formulated by Crammer and Singer.

A Non-Local Structure Tensor Based Approach for Multicomponent Image Recovery Problems

no code implementations21 Mar 2014 Giovanni Chierchia, Nelly Pustelnik, Beatrice Pesquet-Popescu, Jean-Christophe Pesquet

In this paper, we extend the NLTV-based regularization to multicomponent images by taking advantage of the Structure Tensor (ST) resulting from the gradient of a multicomponent image.

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