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Research


1) Main interests

My main interest is focused on developing Bayesian, variational and hybrid methods for solving inverse problems in application to medical imaging and remote sensing.

Methods

Applications

  1. Image reconstruction (MRI, pMRI, MRSI)
  2. Tumor relapse prediction (MRSI, MRI)
  3. Brain activity analysis (fMRI, detection-estimation)
  4. EEG source localization
  5. Drowsiness detection (EEG, ECG)
  1. Change detection (multi-temporal and hyperspectral data)
  2. Hyperspectral unmixing
  3. Anomaly detection

2) Projects


  • Assessment of the risks of disorders in physiological signals (2019-2020).
        Funding : 12 000 €- Toulouse Tech Transfer (pré-maturation)
  • Colored coded aperture design for compressive spectral unmixing in farming product images (2015-2016)
        Funding : ECOS Nord (C16M01)
        Partners : IRIT, Universidad Industrial de Santander

  • Analysis of multi-temporal images by joint detection-estimation: detection of changes in multi-temporal optical images (2015-2016)
        Funding : 50 000 € - CNES (# 0010105785, R & T : R-S14-OT-0004-075)
        Partners : Tésa, IRIT, CNES

  • OPTIMISME Bis:( 2016) 
        Funding : 15 000 €- CNRS
        Partners : LIGM, LJLL, IRIT, Laboratoire de Physique de l’ENS de Lyon, INT, I2M

  • OPTIMISME : design of a new generation of parallel algorithms exploiting recent advances in stochastic optimization for processing large amounts of data (2015)
        Funding : 30 000 € - CNRS
        Partners : LIGM, LJLL, IRIT, Laboratoire de Physique de l’ENS de Lyon, INT, I2M

  • Telemetry analysis for diagnosis: analysis of satellite telemetry data for anomaly detection (2014-2015)
        Funding : 50 000 € - CNES (# 141531, R &T14 : BS-0003-048)
        Partners : Tésa, IRIT, CNES, Université de Nice Sophia Antipolis (Lab. J.L. Lagrange )

  • DynBrain :Reconstruction of Brain Dynamic EEG images (2012 - 2013)
        Funding : 22 253 €- STIC -AmSUd Program
        Partners : IRIT-INPT, Univ. Sanata Catarina - Brazil, ITBA- Buenos Aires

3) Students

Current PhD. Students
Former PhD. Students

4) Collaborations

5) Thesis

Topic: Parallel Magnetic Resonance Imaging reconstruction problems using wavelet representations
Supervisors: Jean-Christophe PESQUET and Philippe CIUCIU
Team: Signal and Communications, IGM LabInfo, UMR8049, University of Marne la Vallee.
Research context:
To reduce scanning time or improve spatio-temporal resolution in some MRI applications, parallel MRI acquisition techniques with multiple coils have emerged since the early 90's as powerful methods. In these techniques, MRI images have to be reconstructed from acquired undersampled "k-space" data. To this end, several reconstruction techniques have been proposed such as the widely-used SENSitivity Encoding (SENSE) method. However, the reconstructed images generally present artifacts due to the noise corrupting the observed data and coil sensitivity profile estimation errors. In this work, we present novel SENSE-based reconstruction methods which proceed with regularization in the complex wavelet domain so as to promote the sparsity of the solution. These methods achieve accurate image reconstruction under degraded experimental conditions, in which neither the SENSE method nor standard regularized methods (e.g. Tikhonov) give convincing results. The proposed approaches relies on fast parallel optimization algorithms dealing with convex but non-differentiable criteria involving suitable sparsity promoting priors. Moreover, in contrast with most of the available reconstruction methods which proceed by a slice by slice reconstruction, one of the proposed methods allows 4D (3D + time) reconstruction exploiting spatial and temporal correlations. The hyperparameter estimation problem inherent to the regularization process has also been addressed from a Bayesian viewpoint by using MCMC techniques. Experiments on real anatomical and functional data show that the proposed methods allow us to reduce reconstruction artifacts and improve the statistical sensitivity/specificity in functional MRI.