TCI Team

Head : Lotfi CHAARI

The research activity of the TCI team focuses on Images, as spatial, temporal, and/or spectral representation of physical phenomena. The team is interested in models and methods for image processing and interpretation in three different domains: medical imaging, remote sensing, and the French sign language (LSF). The Image (the team’s main research topic) is addressed by formulating image processing problems such as:

  • reconstruction, restoration, super-resolution
  • segmentation, classification
  • registration, change detection, motion analysis, fusion

Throughout these problems, members for the team are interested in a set of shared challenges inherent to the image formation process and to the underlying physical phenomena, particularly:

  • data quality and variability: 1) noise, aretfacts, missing data; 2) inter-region, inter-patient, inter-scene variability
  • multiple constraints: 1) spatial, temporal, spectral; 2) regularity, singularity, sparsity
  • dimensionality curse: very large number of parameters, insufficient datasets
  • multi-modality: 1) coherence and complementarity; 2) incompatibility in spatial, temporal and spectral scales

To handle these challenges, the team develops methodological tools for modeling and computing, particularly:

  • modeling: statistics, geometry, graphs, PDE, Bayesian methods
  • computing: optimization, sampling, parallel computing, regularization

The specific aspect of the TCI research lies in the unified approach adopted throughout the three domains. Precisely, a consistent scientific approach is considered for medical imaging, remote sensing and LSF, where models and methods are developed based on the underlying physical phenomena. Consequently, the team aims at developing shared methodological tools for the three domains. This specific aspect is illustrated through the following current research topics:

  • Bayesian methods and stochastic simulation methods, variational approaches and convex optimization for medical image processing and remote sensing
  • Parallel iterative methods for dynamic medical image filtering with strongly non-linear EDP models for convection-diffusion
  • Information geometry for preconditioning optimization problems applied to parameter estimation and medical image segmentation
  • Optical and radar (satellite, embedded sensors) image processing for automated guidance of groups of vehicles (cars, drones…)
  • Elaboration of domain specific sign-lexicon and gesture recognition for LSF

Medical imaging

In medical imaging, the team is interested in anatomic (CT, MRI, HFUS, OCT, Confocal microscopy) and functional (PET, fMRI, MrsI, EEG) images. Two application domains are the most frequently addressed: oncology and brain activity. For oncology, the team currently studies subjects such as tissue heterogeneity for tumor characterization, organs and tumors segmentation and evolution, therapeutic assessment and follow-up, tumor response and relapse prediction, and physiological motion compensation. For brain activity, the team conducts research projects on epilepsy and prediction of awakening in traumatized comatose. The team is particularly interested in dynamic images (3D + t) and multi-modal functional images.

Remote sensing

In remote sensing, the team is interested in multi-modality for change detection, unmixing, and guidance of groups of vehicles. Image modalities currently under study include radar (SAR, GPR), hyperspectral, optics and infrared.

French sign language

The French sign language makes a large research field that covers different and complementary domains, such as illustrated in the following figure :

In this domain, TCI is interested in the analysis and interpretation of communication gestures and attitudes made by persons observed with a vision system. The aim is to detect and track body components (hands, face, chest), to reconstruct the persons’ 3D posture, to analyze expressions, to finally make the linguistic interpretation of this information by recovering the semantics. To account for the variability of the human body and the complexity of the sign language, prior knowledge and constraints are incorporated throughout the process. Accordingly, the team’s research activity concentrates on dynamic models for gestures and face expression, and models of the sign language; while exploiting these models in interpretation methods. The team works also on designing and analyzing sign lexicons for specific domains, such as mathematics.


Medical imaging and Remote sensing
Machine learning, Inverse problems and multimodal fusion
Modelling and statistical image processing
Simulation and intensive computing

Members team

Permanent members
Non-permanent members

publications team

International journals articles
  • Thierry Garcia, Pierre Spitéri, Lilia Ziane Khodja, Raphael Couturier

    Coupling parallel asynchronous multisplitting methods with Krylov methods to solve pseudo-linear evolution 3D problems

    Journal of computational science, Elsevier, 2021, 51, pp.101303. ⟨10.1016/j.jocs.2021.101303⟩


  • Mohamed Fakhfakh, Bassem Bouaziz, Faiez Gargouri, Lotfi Chaâri

    ProgNet: COVID-19 Prognosis Using Recurrent and Convolutional Neural Networks

    The Open Medical Imaging Journal, 2020, 12 (1), pp.11-12. ⟨10.2174/1874347102012010011⟩


  • Walma Gharbi, Lotfi Chaâri, Amel Benazza-Benyahia

    Unsupervised Bayesian change detection for remotely sensed images

    Signal, Image and Video Processing, Springer Verlag, 2020, 14, pp.1-8. ⟨10.1007/s11760-020-01738-9⟩


  • Lotfi Chaari, Olga Golubnitschaja

    Covid-19 pandemic by the “real-time” monitoring: the Tunisian case and lessons for global epidemics in the context 3PM strategies

    EPMA Journal : Journal of Predictive, Preventive and Personalized Medicine – PPPM, 2020, 11 (2), pp.133-138. ⟨10.1007/s13167-020-00207-0⟩


  • Mohamed Fakhfakh, Lotfi Chaâri, Nizar Fakhfakh

    Bayesian curved lane estimation for autonomous driving

    Journal of Ambient Intelligence and Humanized Computing, Springer, 2020, 11, pp.4133-4143. ⟨10.1007/s12652-020-01688-7⟩


  • Achraf Ammar, Michael Brach, Khaled Trabelsi, Hamdi Chtourou, Omar Boukhris, Liwa Masmoudi, Bassem Bouaziz, Ellen Bentlage, Daniella How, Mona Ahmed, Patrick Müller, Notger Müller, Asma Aloui, Omar Hammouda, Laisa Liane Paineiras-Domingos, Annemarie Braakman-Jansen, Christian Wrede, Sofia Bastoni, Carlos Soares Pernambuco, Leonardo Mataruna, Morteza Taheri, Khadijeh Irandoust, Aïmen Khacharem, Nicola Bragazzi, Karim Chamari, Jordan Glenn, Nicholas Bott, Faiez Gargouri, Lotfi Chaari, Hadj Batatia, Gamal Mohamed Ali, Osama Abdelkarim, Mohamed Jarraya, Kais El Abed, Nizar Souissi, Lisette van Gemert-Pijnen, Bryan Riemann, Laurel Riemann, Wassim Moalla, Jonathan Gómez-Raja, Monique Epstein, Robbert Sanderman, Sebastian Schulz, Achim Jerg, Ramzi Al-Horani, Taiysir Mansi, Mohamed Jmail, Fernando Barbosa, Fernando Ferreira-Santos, Boštjan Šimunič, Rado Pišot, Andrea Gaggioli, Stephen Bailey, Jürgen Steinacker, Tarak Driss, Anita Hoekelmann

    Effects of COVID-19 Home Confinement on Eating Behaviour and Physical Activity: Results of the ECLB-COVID19 International Online Survey

    Nutrients, MDPI, 2020, 12 (6), pp.1583. ⟨10.3390/nu12061583⟩


  • Farida Achemine, Abdelkader Merakeb, Moussa Larbani, Philippe Marthon

    Z-equilibria in Bi-matrix Games with Uncertain Payoffs

    RAIRO Operations Research, 2020, 54 (2), pp.393–412. ⟨10.1051/ro/2019007⟩


  • Antonio Quintero Rincón, Carlos d’Giano, Hadj Batatia

    A quadratic linear-parabolic model-based EEG classification to detect epileptic seizures

    The Journal of Biomedical Research, 2020, 34 (3), pp.203-210. ⟨10.7555/JBR.33.20190012⟩


  • Valentin de Bortoli, Alain Durmus, Marcelo Pereyra, Ana Fernandez Vidal

    Efficient stochastic optimisation by unadjusted Langevin Monte Carlo. Application to maximum marginal likelihood and empirical Bayesian estimation

    Statistics and Computing, Springer Verlag (Germany), In press


  • Siwar Chaabene, Lotfi Chaâri, Abdelaziz Kallel

    Bayesian sparse regularization for parallel MRI reconstruction using Complex Bernoulli-Laplace mixture priors

    Signal, Image and Video Processing, Springer Verlag, 2019, 14, pp.445-453. ⟨10.1007/s11760-019-01567-5⟩


  • National journals articles
  • Antonio Quintero Rincón, Máximo Flugelman, Jorge Prendes, Carlos d’Giano

    Study on epileptic seizure detection in EEG signals using largest Lyapunov exponents and logistic regression

    Revista Argentina de Bioingeniería, 2019, 23 (2), pp.17-24


  • National journals articles
    Special issues of journal
    International conferences articles
  • Antonio Quintero Rincón, Carlos D’giano, Hadj Batatia

    Mu-suppression detection in motor imagery electroencephalographic signals using the generalized extreme value distribution

    International Joint Conference on Neural Networks (IJCNN 2020), Jul 2020, Glasgow, United Kingdom. pp.1-5, ⟨10.1109/IJCNN48605.2020.9206862⟩


  • Sana Zorgui, Siwar Chaabene, Hadj Batatia, Lotfi Chaâri

    Lentigo detection using a deep learning approach

    International Conference On Smart Living and Public Health (ICOST 2020), Jun 2020, Hammamet, Tunisia. pp.1-5, ⟨10.1007/978-3-030-51517-1_8⟩


  • Walma Gharbi, Lotfi Chaari, Amel Benazza-Benyahia

    Joint Bayesian Hyperspectral Unmixing for change detection

    Mediterranean and Middle-East Geoscience and Remote Sensing Symposium (M2GARSS 2020), Mar 2020, Tunis, Tunisia. pp.37-40, ⟨10.1109/M2GARSS47143.2020.9105275⟩


  • Pierre Spiteri, Liane Ziane-Khodja, Raphaël Couturier

    Asynchronous parallel multi-splitting mixed methods

    6th International Conference on Parallel, Distributed, GPU and Cloud Computing for Engineering (PARENG 2019), Jun 2019, Pécs, Hungary. pp.1-11, ⟨10.4203/ccp.112.15⟩


  • P. Gonzalez, Thierry Garcia, Pierre Spiteri, C. Tauber

    Simultaneous filtering and sharpening of vector-valued images with numerical schemes

    10th International Conference on Pattern Recognition Systems (ICPRS-2019), 2019, Tours, France. pp.11 (58-63), ⟨10.1049/cp.2019.0249⟩


  • Itebeddine Ghorbel, Walma Gharbi, Lotfi Chaari, Amel Benazza-Benyahia

    Bayesian compressed sensing for IoT : application to EEG recording

    1st International Conference on Digital Health Technologies – ICDHT 2018, Oct 2018, Sfax, Tunisia. pp.53-60


  • Raphaël Smith, Adrian Basarab, Bertrand Georgeot, Denis Kouamé

    Adaptive transform via quantum signal processing: application to signal and image denoising

    IEEE International Conference on Image Processing (ICIP 2018), Oct 2018, Athènes, Greece. ⟨10.1109/ICIP.2018.8451044⟩


  • Kahina Louadj, Fethi Demim, Abdelkrim Nemra, Philippe Marthon

    An Optimal Control Problem of Unmanned Aerial Vehicle

    5th International Conference on Control, Decision and Information Technologies (CoDIT 2018), Apr 2018, Thessaloniki, Greece. pp.751–756, ⟨10.1109/CoDIT.2018.8394830⟩


  • Kahina Louadj, Fethi Demim, Abdelkrim Nemra, Mohamed Aidene, Philippe Marthon, Hocine Iddir

    Optimization of Electricity Consumption in a Building

    5th International Conference on Control, Decision and Information Technologies (CoDIT 2018), Apr 2018, Thessaloniki, Greece. pp.865–869, ⟨10.1109/CoDIT.2018.8394953⟩


  • Siwar Chaabene, Lotfi Chaâri, Abdelaziz Kallel

    Sparse Bayesian pMRI Reconstruction With Complex Bernoulli-Laplace Mixture Priors

    4th IEEE Middle East Conference on Biomedical Engineering (MECBME 2018), Mar 2018, Tunis, Tunisia. pp.193-197


  • National conferences articles
  • Amal Boudaya, Bassem Bouaziz, Siwar Chaabene, Lotfi Chaâri, Achraf Ammar, Anita Hökelmann

    EEG-based Hypo-vigilance detection using convolutional neural network

    18th International Conference Smart Homes and Health Telematics (ICOST 2020), Jun 2020, Hammamet, Tunisia. pp.69-78


  • Yessrine Abichou, Siwar Chaabene, Lotfi Chaari

    A sleep monitoring method with EEG signals

    International Conference on Digital Health Technologies (ICDHT), Dec 2019, Hammamet, Tunisia. pp.1-8


  • Mohamed Fakhfakh, Nizar Fakhfakh, Lotfi Chaari

    Robust lane Extraction using Two-Dimension Declivity

    17th International Conference on Artificial Intelligence and Soft Computing (ICAISC), Jun 2018, Zakopane, Poland. pp.14-24, ⟨10.1007/978-3-319-91262-2_2⟩


  • Houssem Khochemane, Hacène Boutabia, Pierre Spiteri, Ming Chau

    The asynchronous iterations applied to the modified porous medium equation

    Journées Scientifiques Nationales (JSN 2017), Nov 2017, Skikda, Algeria. pp.1-4


  • Rose Sfeir, Jérôme Michetti, Bilal Chebaro, Franck Diemer, Adrian Basarab, Denis Kouamé

    Dental root canal segmentation from super-resolved 3D cone beam computed tomography data

    IEEE Nuclear Science Symposium and Medical Imaging Conference (2017), Oct 2017, Atlanta, United States. pp.1-2


  • Jean-Baptiste Puel, Bérengère Mathieu, Alain Crouzil

    Une application distribuée pour l’enseignement du paysage

    Journées Géomatique, Enseignement & Apprentissage (GET 2017), Jan 2017, Toulouse, France. pp. 23-28


  • Conferences articles without published proceedings
  • Lotfi Chaari

    Digital Health Approach for Predictive, Preventive, Personalised and Participatory Medicine

    Springer, 10, pp.XVI, 88, 2019, Advances in Predictive, Preventive and Personalised Medicine, 978-3-030-11799-3. ⟨10.1007/978-3-030-11800-6⟩


  • Books edition Books parts
    Thesis and HDR
    • Ming Chau

      Itérations parallèles asynchrones et workflows de simulation numérique

      HDR, Institut National Polytechnique de Toulouse, 2016.


    • Yan Wang

      Détection des changements à partir de photographies

      Master’s Thesis, Université de Toulouse, July 2016.

      Abstract URL :

    • Andréa Laruelo


      Master’s Thesis, Université Paul Sabatier, May 2016.


    • Sawssen Jalel

      Optimisation de la navigation robotique

      Master’s Thesis, Institut National Polytechnique de Toulouse, December 2016.


    • Mohanad Y.S. Albughdadi

      Bayesian joint detection-estimation in functional MRI with automatic parcellation and functional constraints

      Master’s Thesis, Institut National Polytechnique de Toulouse, September 2016.


    • Ningning Zhao

      Deconvolution, Segmentation and Restoration of Ultrasound Images

      Master’s Thesis, Institut National Polytechnique de Toulouse, October 2016.


    • Teodora Szasz

      Advanced beamforming techniques in ultrasound imaging and the associated inverse problems

      Master’s Thesis, Université Paul Sabatier, October 2016.


    • Zhouye Chen

      Reconstruction of enhanced Ultrasound images from compressed measurements

      Master’s Thesis, Université Paul Sabatier, October 2016.


    • Adrian Basarab

      Quelques problèmes inverses en imagerie ultrasonore

      HDR, Université Paul Sabatier, November 2016.


    • Meriem Djeddi

      Modélisation multifractale et segmentation par contours actifs d’images d’ultrasons de haute fréquence. Application au mélanome de la peau.

      Master’s Thesis, Institut National Polytechnique de Toulouse, September 2015.



    Contracts team

    AcronymeTitreResp. scDébut – fin
    [Contract completed]
    autre Communication à base de signes entre agents réels et virtuels
    2007 – 2012
    AcronymeTitreResp. scDébut – fin
    [Contract completed]
    autre Collaborative project, DICTA-SIGN, Sign Language Recognition, Generation and Modelling with application in Deaf Communication Christophe COLLET
    2009 – 2012
    AcronymeTitreResp. scDébut – fin
    [Contract completed]
    Suite logicielle pemettant de communiquer et travailler en langage des signes
    2011 – 2012
    Monday 20 December 2021 – Wednesday 22 December 2021
    ICDHT 2021 – International Conference on Digital Health Technologies
    Hammamet (Tunisie) (Tunisie)
    #congres Know more
    Tuesday 16 October 2018, 10h00
    Cardiac Motion Estimation In Ultrasound Images using a Sparse Representation and Dictionary Learning
    Nora Leïla OUZIR – Team MINDS – IRIT INP-ENSEEIHT, Salle des thèses
    Wednesday 25 April 2018, 14h00
    Calcul haute performance pour la simulation d’interactions fluide-structure
    Vincent PARTIMBENE – Team TCI – IRIT INP-ENSEEIHT, Salle des thèses
    Friday 8 December 2017, 10h00
    Modélisation et traitement statistique d’images de microscopie confocale : application en dermatologie
    Abdelghafour HALIMI – Team TCI – IRIT INP-ENSEEIHT, Salle des thèses
    Wednesday 15 November 2017, 14h00
    Segmentation interactive multiclasse d’images par classification de superpixels et optimisation dans un graphe de facteurs
    Bérengère MATHIEU – Team TCI – IRIT UT3 Paul Sabatier, IRIT, Salle des Thèses
    Tuesday 17 October 2017, 10h00
    Modeling spatial and temporal variabilities in hyperspectral image unmixing
    Pierre-Antoine THOUVENIN – Team SC – IRIT INP-ENSEEIHT, Salle des thèses
    Thursday 2 March 2017, 10h00
    Bayesian M/EEG Source Localization with possible Joint Skull Conductivity Estimation
    Facundo COSTA – Team TCI – IRIT INP-ENSEEIHT, Salle des thèses
    Friday 16 December 2016, 14h00
    Optimisation de la navigation robotique
    Sawssen JALEL – Team TCI – IRIT ENSEEIHT, Salle F501
    Friday 21 October 2016, 10h00
    Reconstruction of enhanced ultrasound images from compressed measurements
    Zhouye CHEN – Team TCI – IRIT UT3 Paul Sabatier, IRIT, Auditorium J. Herbrand
    Thursday 20 October 2016, 10h00
    Inverse problems in ultrasound imaging – Applications in image deconvolution, segmentation and super-resolution
    Ningning ZHAO – Team SC, Team TCI – IRIT INP-ENSEEIHT, Salle des thèses
    Friday 14 October 2016, 10h00
    Advanced beamforming techniques in ultrasound imaging and the associated inverse problems
    Teodora SZASZ – Team TCI – IRIT UT3 Paul Sabatier, IRIT, Auditorium J. Herbrand
    Monday 20 December 2021 – Wednesday 22 December 2021
    ICDHT 2021 – International Conference on Digital Health Technologies
    Hammamet (Tunisie) (Tunisie)
    #congres Know more
    Tuesday 30 June 2015 – Friday 3 July 2015
    Les Journées nationales du DEVeloppement logiciel 2015 de l’Enseignement Supérieur et de la Recherche
    #congres Know more
    Friday 16 February 2018, 14h00 – 16h00
    Patch-based regularization in multiband imaging inverse problems
    José BIOUCAS – University of Lisboa (Portugal) TéSA, 7 Boulevard de la Gare, Toulouse
    Tuesday 28 March 2017, 10h00
    Approches bayésiennes, variationnelles et hybrides pour le traitement d’images médicales
    Lotfi CHAARI – Team TCI – IRIT INP-ENSEEIHT, Salle des thèses
    Friday 25 November 2016, 10h00
    Quelques problèmes inverses en imagerie ultrasonore
    Adrian BASARAB – Team TCI – IRIT UT3 Paul Sabatier, IRIT, Auditorium J. Herbrand
    Tuesday 12 May 2015, 10h00
    Modélisation statistique, problèmes variationnels et inférence bayésienne en traitement d’images médicales
    Hadj BATATIA – Team TCI – IRIT INP-ENSEEIHT, Salle des theses
    Monday 8 April 2019
    ado2019 : Journée thématique sur les autorités de données
    Meteo-France, Toulouse
    Monday 4 December 2017
    Journée sur l’appel COGITER – InfraMED 2017 – COGITER – INFRAMED 2017 – COGITER – INFRAMED 2017
    UT3 Paul Sabatier, IRIT, Auditorium J. Herbrand