Habilitation (HDR) defense of Loïc Denis

"Quelques contributions méthodologiques en reconstruction d'images"

Abstract

Image reconstruction is the process of estimating images from noisy and possibly indirect measurements. It requires the development of signal processing methods and efficient algorithms. Reconstruction methods are based on three fundamental ingredients : (i) a modeling of the measurements (from wave propagation to the collection by the instrument and its detector) ; (ii) a modeling of the class of images under study (image regularity, statistical distribution of natural images) ; (iii) an estimator that produces a reconstruction that is both in good agreement with the measurements, according to (i), and that fits the model of images (ii).
This last decade, I have considered image reconstruction problems that arise in several fields : remote sensing (synthetic aperture radar imaging), holographic microscopy (for 3D optical metrology and biomedical imaging) and astronomy (high angular resolution and high contrast imaging). I developed methods based on the inverse problems framework, leading to algorithms that rely on numerical optimization strategies (large scale optimization, non-smooth optimization, discrete optimization by graph-cuts), and patch-based approaches.
Image reconstruction is still a hot research topic and several directions for future research can be considered, either to address important applicative challenges, or to improve the reconstruction methods. In particular, techniques leading to fully automatic reconstruction algorithms and approaches to learn complex reconstruction models (like deep convolution networks) are very promising.

Committee

Reviewers (rapporteurs)
M. Jean-François Aujol, Professeur à l'Université de Bordeaux
M. Jérôme Idier, Directeur de Recherche CNRS au laboratoire LS2N de Nantes
M. Emmanuel Trouvé, Professeur à l'Université Savoie-Mont Blanc

Examiner (Examinateurs)
M. Andrés Almansa, Directeur de Recherche CNRS au laboratoire MAP5 de Paris
M. Jose Bioucas-Dias, Professeur à l'Université de Lisbonne (Portugal)
M. Marc Sebban, Professeur à l'Université de Saint-Etienne

Academic supervisor (tutrice)
Mme. Florence Tupin, Professeure à Télécom Paristech

Invited member (invité)
M. Eric Thiébaut, Astronome à l'Observatoire de Lyon               

The defense will be done in english