Laurent Risser, PhD
Research engineer with CNRS
Institut de mathématiques de Toulouse (IMT)
Statistics and Probability team (ESP)
Learning, Optimization, Complex data (AOC) team-project

1R1 building, office 107
Université Paul Sabatier
118 route de Narbonne
31062, Toulouse Cedex 9
+33 (0)561 557 477

Picture: Patrick Dumas



Welcome to my website! Below is a brief summary of my career and studies. More details are given in the rest of the website.

Main interests:

Research: Medical image analysis and data mining. More specifically, I'm interested in medical image registration and complex data analysis, i.e. the analysis of small data sets in which each observation has a very high dimension. In both cases, data representation and regularisation models are of particular interest.

Engineering: Image and graphs analysis in general. Program development using C++ and Python. GPU computing using OpenCL.

Career:

2012-.: Fellow research engineer at CNRS - Toulouse Mathematics Institute (IMT), France.

2011: Research fellow at the Biomedical Image Analysis Laboratory with Julia A. Schnabel (Invited fellow until end 2014). Institute of Biomedical Engineering, University of Oxford, UK.

2009-2010: Research assistant at the Biomedical Image Analysis Group and the Institute for Mathematical Sciences with Daniel Rueckert and Darryl Holm. Imperial College, London, UK.

2007-2008: Researcher/Engineer at the Computer Assisted Neuroimaging Laboratory with Philippe Ciuciu. Neurospin, CEA Saclay, France.

2003-2006: Junior lecturer in Fluid Mechanics. Department of Mathematics and Computer science, Paul Sabatier University, Toulouse, France.

Studies - qualifications:

2011: Teaching qualification in Applied mathematics and applications of mathematics (CNU 26)

2007: Teaching qualification in Mechanics, mechanical engineering, civil engineering (CNU 60)

2003-2007: PhD at the Fluid Mechanics Institute of Toulouse with Franck Plouraboué. Paul Sabatier University, Toulouse, France.

2002-2003: Master 2 in Computer Science. Major in Image analysis. Paul Sabatier university, Toulouse, France.

2000-2002: Licence 3, Master 1 in Mathematical Engineering. Major in Scientific Computing (PDEs and optimization). Paul Sabatier university, Toulouse, France.

1998-2000: Licence 1,2 in Mathematics, Computer Science and applications. Paul Sabatier university, Toulouse, France.

Awards and Grants:

2016: Grant for a PhD thesis Regression models for non-Euclidean and high-dimensional data founded by Region Midi-Pyrénées (now Occitanie). Obtained with J.-M. Loubes (IMT, Univ. Toulouse) and P. Balaresque (AMIS, CNRS).

2016: Member of the ANR granted project Voice4PD-MSA (Differential diagnosis between Parkinson's disease and Multiple System Atrophy using digital speech analysis) with K. Daoudi (INRIA Bordeaux, PI), J. Mauclair (IRIT, Univ. Toulouse), W. Meissner (CHU Bordeaux), A. Pavy-Le-Traon (CHU Toulouse), S. Déjean (IMT - Univ. Toulouse). Co-responsible for statistical analyses with S. Déjean.

2015: Member of the project Fluidbrain founded by the Midi-Pyrénées region and INSERM with E. Schmidt (PI, INSERM 825 - CHU Toulouse), P. Celsis (INSERM 825 - CHU Toulouse), P. Payoux (INSERM 825 - CHU Toulouse), P. Swider (IMFT), P. Besse (IMT - INSA), S. Déjean (IMT - UPS). Responsible for the work package dealing with data integration.

2015: Member of the project SysBio founded by INSERM with E. Dupré (PI, INSERM 1043 - CHU Toulouse), L. Ysebaert (CHU Toulouse), E. Chatelut (Institut Claudius Regaud), F. Courbon (CHU Toulouse), F. Malgouyres (UPS - IMT), S. Gadat (UT1/TSE - associate IMT). Responsible for the development of image analysis strategies on 3D Slicer.

2014: Member of the ANR granted project Numerical Schemes using Lattice Basis Reduction with J.-M. Mirebeau (PI, Univ. Paris Dauphine), L. Cohen (Univ. Paris Dauphine) and J. Fehrenbach (Univ. Paul Sabatier, Institut de Mathématiques de Toulouse) (website).

2014: Travel grant CNRS / University of Oxford collaboration scheme. Grant obtained in collaboration with Julia A. Schnabel.

2013: PI of an AO1/Université Paul Sabatier grant. Grant obtained in collaboration with CerCo Toulouse (in particular M. Mescam and C. Fonta).

2012: Travel grant CNRS / University of Oxford collaboration scheme. Grant obtained in collaboration with Julia A. Schnabel.

2010: Co-author with Darryl D. Holm (Principal Investigator) and François-Xavier Vialard of the ERC projet: Five Grand Challenges in Computational Anatomy.

2008: French national prize "La recherche" 2008 - human health mention. Prize obtained with the team members Franck Plouraboué, Caroline Fonta, Peter Cloetens and Xavier Descombes on my PhD work. This prize rewards pluridisciplinary research works.

2006: PI of a grant to fund an extension of one year to my PhD work. Grant from the Fondation pour la Recherche Médicale (French Foundation for Medical Research) with F. Plouraboué and C. Fonta.


Softwares / Structuring projects:

uTIlzreg: Diffeomorphic registration of 3D images available on sourceforge. Explanations about uTIlzreg are given here.

CampuStat: Establishing the link between pluridisciplinary labs/companies and the team of statistics at Institut de Mathématiques de Toulouse: here.

Responsibilities / organizating committees:

2016: Co-organiser of the MASCOT-NUM 2016 meeting, dealing with stochastic methods for the analysis of numerical codes.

12/2015 - .: Representative of the technical and administrative personnel at the Mathematics Institute of Toulouse laboratory Council. Elected for 4 years with I. Guichard.

2015 : Co-organiser of the French conference Journées de probabilités 2015, dealing with probability.

2014 - .: Member of the editorial board of AIMS Medical Science (link).

2014: Co-organiser of the French conference Journées MAS 2014, dealing with stochastic modelling and statistics. Proceedings are here.


Journal papers:

Roque T., Risser L., Kersemans V., Smart S., Allen D., Kinchesh P., Gilchrist S., Gomes A., Schnabel J.A., Chappell M.: An image-Driven 3-D Model of Tumour Growth IEEE Transactions on Medical Imaging (submitted)

Gadat S., Gavra I., Risser L.: How to calculate the barycenter of a weighted graph. Informs: Mathematics of Operations Research (submitted)

Braga J., Bouvier P., Dherbey J. R., Balaresque P., Risser L., Loubes J.-M., Dumoncel J., Duployer B., Tenailleau C.: Echoes from the past: new insights into the early hominin cochlea from a phylo-morphometric approach. Comptes Rendus Palevol, 2017

Schmah T., Risser L., Vialard F.X.: Diffeomorphic image matching with left-invariant metrics. Book chapter in Fields Institute Communications 73 - Geometry, Mechanics, and Dynamics: The Legacy of Jerry Marsden (book), 2015

Ribes S., Didierlaurent D., Decoster N., Gonneau E., Risser L., Feillel V. and Caselles O.: Automatic segmentation of breast MR images through a Markov random field statistical model. IEEE Transactions on Medical Imaging (link), 2014

Papież B.W., Heinrich M.P., Fehrenbach J., Risser L., Schnabel J.A.: An implicit sliding-motion preserving regularisation via bilateral filtering for deformable image registration. Medical Image Analysis (link), 2014

Fiot J.B., Raguet H., Risser L., Cohen L.D., Fripp J., Vialard F.X., ADNI: Longitudinal deformation models, spatial regularizations and learning strategies to quantify Alzheimer's disease progression. NeuroImage: Clinical, 2014 (link).

Vincent T., Badillo S., Risser L., Chaari L., Bakhous C., Forbes F., Ciuciu P.: Flexible multivariate hemodynamics fMRI data analyses and simulations with PyHRF. Frontiers in Neuroscience. DOI:10.3389/fnins.2014.00067, 2014 (link)

Cifor A., Risser L., Chung D., Anderson E.M., Schnabel J.A.: Hybrid Feature-based Diffeomorphic Registration for Tumour Tracking in 2-D Liver Ultrasound Images. IEEE Transactions on Medical Imaging, 2013 (link).

Baluwala H.Y., Risser L., Schnabel J.A., Saddi K.A.: Towards a Physiologically Motivated Registration of Diagnostic CT and PET/CT of Lung Volumes. Medical Physics 40(02), 2013 (link).

Risser L., Vialard F.X., Baluwala H.Y., Schnabel J.A.: Piecewise-Diffeomorphic Image Registration: Application to the Motion Estimation between 3D CT Lung Images with Sliding Conditions Medical Image Analysis 2012, (link).

Bruveris M., Risser L., Vialard F.X.: Mixture of Kernels and Iterated semidirect Product of Diffeomorphisms Groups. SIAM Multiscale Modeling and Simulation 10 (4), pp: 1344-1368, 2012, (link).

Guibert R., Fonta C., Risser L., Plouraboué F.: Coupling and robustness of intra-cortical vascular territories NeuroImage. Accepted 13.04.12 (link).

Vialard F.X., Risser L., Rueckert D., Holm D.: Diffeomorphic Atlas Estimation using Geodesic Shooting on Volumetric Images Annals of the British Machine Vision Association, 2012, (link).

Risser L., Vialard F.X., Wolz R., Murgasova M., Holm D., Rueckert D., ADNI: Simultaneous Multiscale Registration using Large Deformation Diffeomorphic Metric Mapping. IEEE Transactions on Medical Imaging DOI: 10.1109/TMI.2011.2146787, 2011, (link).

Vialard F.X., Risser L., Rueckert D., Cotter C.J.: Diffeomorphic 3D Image Registration via Geodesic Shooting using an Efficient Adjoint Calculation. International Journal of Computer Vision DOI: 10.1007/s11263-011-0481-8, 2011, (link).

Risser L., Vincent T., Forbes F., Idier J., Ciuciu P. Min-max extrapolation scheme for fast estimation of 3D Potts field partition functions. Application to the joint detection-estimation of brain activity in fMRI. Journal of Signal Processing Systems. 60(1), DOI:10.1007/s11265-010-0505-6, 2010 (link)

Ciuciu P., Vincent T., Risser L., Donnet S. A joint detection-estimation framework for analysing within-subject fMRI data. Journal de la Société Française de Statistique. 151(1):58-89, 2010 (link)

Vincent T., Risser L., Ciuciu P., Idier J. Unsupervised spatial mixture modelling for within-subject analysis of fMRI data. IEEE Transactions on Medical Imaging 29(4):1059-1075, 2010 (link)

Risser L., Plouraboué F., Cloetens P., Fonta C. A 3D-investigation shows that angiogenesis in primate cerebral cortex mainly occurs at capillary level. International Journal of Developmental Neuroscience. 27(2), pp. 185-196, 2008, (link).

Risser L., Plouraboué F., Descombes X. Gap Filling in Vessel Networks by Skeletonization and Tensor Voting. IEEE Transactions on Medical Imaging. 27(5), pp. 674-687, 2008, (link).

Risser L., Plouraboué F., Steyer A., Cloetens P., Le Duc G, Fonta C. From homogeneous to fractal normal and tumorous micro-vascular networks in the brain. Journal of Cerebral Blood Flow and Metabolism. 27, pp. 293-303, May 2006, (link).

Conference and workshops with proceedings:

Fort G., Risser L., Ollier E., Samson A.: Algorithmes Gradient-Proximaux Stochastiques. GRETSI 2017. Juan-les-Pins, France 2017.

Bates R., Risser L., Irving B., Papiez B., Kannan P., Kersemans V., Schnabel J.A.: Filling Large Discontinuities in 3D Vascular Networks using Skeleton- and Intensity-based Information. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'15) - LNCS. Munich, 2015, (link).

Vialard F.X., Risser L.: Spatially-varying metric learning for diffeomorphic image registration. A variational framework. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'14) - LNCS. Boston, 2014, (link).


Risser L., Dolius L., Fonta C., Mescam M.: Diffeomorphic registration with self-adaptive spatial regularization for the segmentation of non-human primate brains. International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC'14). Chicago, 2014, (link).

Schmah T., Risser L., Vialard F.X.: Left-invariant metrics for diffeomorphic image registration with spatially-varying regularisation. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'13) - LNCS. Nagoya, 2013, (link).

Papież B.W., Heinrich M.P., Risser L., Schnabel J.A.: Complex lung motion estimation via adaptive bilateral filtering of the deformation field. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'13) - LNCS (Papież B.W. received a Young Scientist award for this paper). Nagoya, 2013, (link).

Cifor A., Risser L., Heinrich M.P., Chung D., Schnabel J.A.: Rigid registration of untracked freehand 2D ultrasound sweeps to 3D CT of liver tumours MICCAI Workshop on Computational and Clinical Applications in Abdominal Imaging (MICCAI-ABDI'13) - LNCS. Nagoya, 2013.

Fiot J.B., Risser L., Cohen L., Fripp J., Vialard F.X.: Local vs global descriptors of hippocampus shape evolution for Alzheimer's longitudinal population analysis MICCAI Workshop on Spatiotemporal Image Analysis for Longitudinal and Time-Series Image Data (MICCAI-STIA'12) - LNCS. Nice, 2012.

Risser L., Heinrich M.P., Matin T., Schnabel J.A.: Piecewise-diffeomorphic registration of 3D CT/MR pulmonary images with sliding conditions IEEE International Symposium on Biomedical Imaging (ISBI'12). Barcelona, 2012, (link).

Cifor A., Risser L., Chung D., Anderson E.M., Schnabel J.A.: Hybrid feature-based Log-demons registration for tumour tracking in 2-D liver ultrasound images IEEE International Symposium on Biomedical Imaging (ISBI'12). Barcelona, 2012, (link).

Bhushan M., Schnabel J.A., Heinrich M.P., Risser L., Brady M., Jenkinson M.: Motion Correction and Parameter Estimation in dceMRI sequences: Application to Colorectal Cancer. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'11) - LNCS. Toronto, 2011, (link).

Risser L., Baluwala H. Schnabel J.A.: Diffeomorphic registration with sliding conditions: Application to the registration of lungs CT images. International Conference on Medical Image Computing and Computer Assisted Intervention - Worshop on Pulmonary Image Analysis (MICCAI-PIA'11). Toronto, 2011.

Risser L., Heinrich M.P., Rueckert D., Schnabel J.A.: Multi-modal diffeomorphic registration using mutual information: Application to the registration of CT and MR pulmonary images. International Conference on Medical Image Computing and Computer Assisted Intervention - Worshop on Pulmonary Image Analysis (MICCAI-PIA'11). Toronto, 2011.

Risser L., Vialard F.X., Serag A., Aljabar P., Rueckert D.: Construction of Diffeomorphic Spatio-temporal Atlases using Kärcher means and LDDMM: Application to Early Cortical Development International Conference on Medical Image Computing and Computer Assisted Intervention - Worshop on Image Analysis of Human Brain Development (MICCAI-IAHBD'11). Toronto, 2011.

Vialard F.X., Risser L., Holm D.D., Rueckert D.: Diffeomorphic Atlas Estimation using Kärcher Mean and Geodesic Shooting on Volumetric Images. Medical Image Understanding and Analysis (MIUA'11). (Top ranked paper) London, 2011, (link)..

Risser L., Vialard F.X., Wolz R., Holm D., Rueckert D. Simultaneous Fine and Coarse Diffeomorphic Registration: Application to the Atrophy Measurement in Alzheimer's Disease. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'10) - Lecture Notes in Computer Science. Beijing, 2010, (link).

Zhang D.P., Risser, L., Vialard F.X., Friman O., Neefjes L., Mollet N., Niessen W., Rueckert D. Coronary Motion Estimation Using Probability Atlas and Diffeomorphic Registration from CTA. International Workshop on Medical Imaging and Augmented Reality (MIAR'10) - Lecture Notes in Computer Science Beijing, 2010.

Risser L., Vialard F.X., Murgasova M., Holm D., Rueckert D. Large Diffeomorphic Registration using Fine and Coarse Strategies. Application to the brain growth characterization. International Workshop on Biomedical Image Registration (WBIR'10) - Lecture Notes in Computer Science 6204, pp. 186--197. Lübeck, 2010.

Zhang D.P., Risser, L., Friman O., Neefjes L., Mollet N., Niessen W., Rueckert D. Nonrigid Registration and Template Matching for Coronary Motion Modeling from 4D CTA. International Workshop on Biomedical Image Registration (WBIR'10) - Lecture Notes in Computer Science. Lübeck, 2010.

Zhang D.P., Risser L., Metz C., Mollet N.R., Niessen W., Rueckert D. Coronary artery motion modeling from 3D cardiac CT sequences. IEEE International Symposium on Biomedical Imaging (ISBI'10). Rotterdam, 2010, (link).

Risser L., Vincent T., Forbes F., Idier J., Ciuciu P. How to deal with brain deactivation in the joint detection-estimation framework? Human Brain Mapping (HBM'10) - Top ranked abstract, Barcelona, Spain, June 2010.

Risser L., Idier J., Ciuciu P. Extrapolation schemes for fast ISING field partition functions estimation. IEEE International Conference on Image Processing (ICIP'09). Cairo, Egypt, November 2009.

Risser L., Vincent T., Ciuciu P., Idier J., Robust Extrapolation Scheme for Fast Estimation of 3D Ising Field Partition Functions: Application to Within-Subject fMRI Data Analysis Internatinal Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'09). London, UK, September 2009, (link).

Risser L., Vincent T., Ciuciu P., Idier J., Schémas d'extrapolation de fonctions de partition de champs de Potts. Application à l'analyse d'image en IRM fonctionnelle. Groupe de Recherche et d'Etudes du Traitement du Signal (GRETSI'09). Dijon, France, September 2009

Fouque A.L., Ciuciu P., Risser L., Vincent T. Mélanges spatiaux gaussiens multivariés pour la classification de paramètres hémodynamiques en IRM fonctionnelle Groupe de Recherche et d'Etudes du Traitement du Signal (GRETSI'09). Dijon, France, September 2009

Risser L., Vincent T., Ciuciu P. Extrapolation Scheme For Fast 3D Ising Field Partition Function Estimation. Application to Bayesian Analysis of Within Subject fMRI Data. Human Brain Mapping (HBM'09).

Vincent T., Risser L., Ciuciu P. Spatially adaptive mixture modeling for analysis of fMRI time series. Human Brain Mapping (HBM'09).

Fouque A.L., Ciuciu P., Risser L. Multivariate spatial Gaussian mixture modeling for statistical clustering of hemodynamic parameters in functional MRI. International Conference on Acoustics, Speech, and Signal Processing (ICASSP'09). Taiwan, April 2009

Risser L., Plouraboué F., Descombes X. Vascular network topology extraction from 3D high resolution X-ray images using tensor voting. 3rd International Conference on Approximation Methods and numerical Modeling in Environment and Natural Resources (MAMERN). Pau, France, 2009

Risser L., Ciuciu P., Aso T., Le Bihan D. Brain activation detection using diffusion-weighted and BOLD fMRI: a comparative study. International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI'08). Workshop on Computational Diffusion MRI. New York, September 2008

Risser L., Plouraboué F., Fonta C. Angiogenesis in brain : a comparative study of local and organizational vascular structures. Neuroscience'08. Washington, USA, 2008.

Risser L., Plouraboué F., Fonta C. Micro-vascular maturation in cerebral cortex: a quantitative high resolution study. Forum of European Neuroscience. Geneva, Switzerland, 2008.

Risser L., Plouraboué F., Fonta C., Steyer A. Cortical micro-vascular inhomogeneities: a high resolution 3D investigation 13th Annual Meeting of the Organization for Human Brain Mapping (HBM). Chicago, USA, 2007.

Risser L., Plouraboué F., Descombes X. Gap Filling in D Vessel Like Patterns with Tensor Voting. 2nd International Conference On Computer Vision Theory and Applications (VISAPP). Barcelona, Spain, 2007.

Risser L., Plouraboué F., Cloetens P., Steyer A., Fonta C. Maturation of marmoset cortical cerebral vascular networks : high-resolution 3D investigations. 35th annual meeting Society for Neuroscience. Washington, DC, 2005, 370.17.

Risser L., Plouraboué F., Fonta C., Cloetens P., Steyer A. Volumes élémentaires représentatifs dans les réseaux microvasculaires. 7èmes Journées d'Etude sur les Milieux Poreux. Bordeaux, France, 2005.

Risser L., Plouraboué F., Cloetens P., Steyer A, Leduc G., Renaud L., Fonta C. Normal and tumoral cerebral vascular networks: high resolution 3D investigations. Novel targeting drugs and radiotherapy. Toulouse, France, 2005, p39

Fonta C., Risser L., Plouraboué F., Renaud L., Cloetens P., Steyer A. X-Ray high resolution vascular network analysis in the cerebral cortex. 4th Forum of European Neuroscience. Lisboa, Portugal, 2004, AO17.8


Misc:

Google scholar profile: here.

DBLP profile: here.

Member of the Toulouse Data Science meetup group.