Search Results for author: Barbara Pascal

Found 7 papers, 3 papers with code

Point Processes and spatial statistics in time-frequency analysis

no code implementations29 Feb 2024 Barbara Pascal, Rémi Bardenet

The zeros of the spectrogram of a noisy signal are then the zeros of a random analytic function, hence forming a Point Process in $\mathbb{C}$.

Denoising Point Processes

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.

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

A covariant, discrete time-frequency representation tailored for zero-based signal detection

1 code implementation8 Feb 2022 Barbara Pascal, Rémi Bardenet

Recent work in time-frequency analysis proposed to switch the focus from the maxima of the spectrogram toward its zeros, which, for signals corrupted by Gaussian noise, form a random point pattern with a very stable structure leveraged by modern spatial statistics tools to perform component disentanglement and signal detection.

Disentanglement

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

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.

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