Guillaume Lauga

I'm a postdoctoral researcher at ENS Lyon, where I defended my thesis in December 2024, supervised by Paulo Gonçalves, Elisa Riccietti and Nelly Pustelnik. I was a member of the Inria OCKHAM team. Starting from July 2025, I will be at Université Côte d'Azur with Samuel Vaiter.

During my PhD, I worked on multilevel optimization methods for proximal based algorithms, with applications to image restoration problems.

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Research

I'm interested in optimization for imaging applications. Since the start of my PhD I investigate the convergence of proximal algorithms tailored for large-scale problems. Such algorithms can take the form of multilevel algorithms but also block-coordinate descent algorithms, which are often used in imaging applications. I also try to apply these algorithms to as many challenging imaging problems I can.

IML FISTA: A Multilevel Framework for Inexact and Inertial Forward-Backward. Application to Image Restoration
Guillaume Lauga, Elisa Riccietti, Nelly Pustelnik, Paulo Gonçalves
SIAM Journal on Imaging Sciences, 2024
Matlab code / arXiv / HAL

IML FISTA: An Inexact Multilevel FISTA. Optimal convergence guarantees on non-smooth convex optimization problems and ability to handle inexact computation of the proximity operator. Some applications to restoration of color and hyperspectral images.

A multilevel framework for accelerating uSARA in radio-interferometric imaging
Guillaume Lauga, Audrey Repetti, Elisa Riccietti, Nelly Pustelnik, Paulo Gonçalves, Yves Wiaux
EUSIPCO, 2024   (Poster)
BASP Group project page / arXiv / HAL

Application of IML FISTA to solve radio-interferometric imaging problems. Hierarchy of approximations built in the observation space rather than in the parameter space.


Website source code from here.