Contrats post-doctoraux

Fast computational hyperspectral imaging
Duration 18 months

Description: We are actively seeking a postdoctoral fellow or an engineer to spearhead the development of a high-speed computational imaging system tailored for hyperspectral imaging. This cutting-edge camera need to be developed to detect Protoporphyrin fluorescence signal, specifically in the context of  glioma resection. The role, funded by ANR, will encompass the full spectrum of responsibilities, from conceptualization of an optical experimental setup, its characterization, the acquisition of hypercubes from ex-vivo and in-vivo glioma and the post-procesing of theses hypercubes.
Challenge: Currently, the total acquisition time is suitable for biopsy samples but impractical for in vivo imaging. In response, our group has developed compressive imaging strategies aimed at reducing the number of patterns required for acquisition, thereby reducing the total acquisition time. While this is a significant advance, it is still insufficient for clinical in vivo applications. Hardware development is needed to increase speed by developing a second experimental setup. Read more

Work location:
CREATIS
Bâtiment Léonard de Vinci
21 avenue Jean Capelle
69621 Villeurbanne cedex FRANCE

Application procedure (CV and motivation letter): Laurent Mahieu-Williame (mahieu@creatis.insa-lyon.fr), Bruno Montcel (bruno.montcel@univ-lyon1.fr)

Ingénieur/Chercheur en physique - Développement logiciel de représentation et de traitement de spectre de la LIBS : de Reconnaissance Automatique et de Simulation (CDD 12 mois H/F)

Description : Le projet de recherche L2-R.A.S. associe le C2RMF (Centre de recherche et de conservation des musées de France), le laboratoire SATIE de Cergy Paris université et le LAPA (CEA). La technique LIBS (Laser-induced breakdown spectroscopy) ou spectrométrie d’émission plasma induit par laser a été mise en évidence dès 1962 juste après l’invention du laser par Théodor Maiman. Il s’agit de focaliser un laser sur un matériau afin de créer un plasma thermique pour en recueillir l’émission atomique. Ainsi la composition élémentaire peut en être déduite voire identifier des fragments moléculaires d’origine de matière organique ou de recombinaison. Sa mise en œuvre est simple, et quasi instantanée mais l’analyse du spectre d’émission optique peut s’avérer rapidement complexe, sensible aux éléments traces et sa quantification difficile si le matériau analyser est multi-structuré ou pollué. L’objectif de ce travail de recherche vise, en intégrant les bases de données spectroscopiques existantes (théoriques et expérimentales), à poursuivre trois objectifs encore aujourd’hui mal maîtrisés. Le premier est de trouver des solutions techniques et mathématiques multimodales efficaces pour identifier, quel que soit le matériel de spectroscopie utilisé, les atomes ou fragments de molécules contenus dans le matériau issu de l’émission du plasma allant des éléments majeurs aux éléments traces (ppm environ). Le second sera de déterminer sur la base de cette identification les conditions de température du plasma généré sur la base d’un outil de simulation visant à vérifier les résultats obtenus. Et, enfin, le dernier est de se rapprocher, au travers de méthode d’intelligence artificielle, réseaux de neurones ou méthodes chimio-métriques et spectroscopiques, d’une nouvelle approche de quantification. Le contexte visé doit pouvoir s’appliquer aux matériaux complexes et multi-structurés du patrimoine afin de pouvoir les décrire en deux ou trois dimensions de façon quantitative, tels les matériaux en aluminium du patrimoine aéronautique ou les aciers archéologiques issus des problématiques patrimoniaux. Lire la suite

Adresse du poste :
Centre de Recherche et de Restauration des Musées de France
14 Quai François Mitterrand
75001 Paris

Contacts : Xueshi Bai (xueshi.bai@culture.gouv.fr), Vincent Detalle (vincent.detalle@cyu.fr) 

Doctoral position on image reconstruction for ultrasound modulated optical tomography (3 years)
Starting: september 2024

Description: Local optical properties of a biological tissue can provide useful information to improve medical diagnosis. However, non-invasive optical imaging deep inside the tissue remains a challenge, because of strong light scattering. The use of the acousto-optic effect between the light and the ultrasound (US) was proposed as a solution to achieve high-resolution images of optical contrast deep inside the tissue: US modulated optical tomography (UOT). So far, UOT was developed on experimental optical bench with focus US, requiring several minutes for data acquisition. The challenge for a clinical use of UOT is the acceleration of the data acquisition by one order of magnitude without degradation of the signal-to-noise ratio. Read more

Work location:
Multimodal Biomedical Imaging Laboratory (BioMaps)
University of Paris-Saclay / French Atomic Energy Commission (CEA) / CNRS / INSERM
Orsay, France

Application procedure (CV and cover letter): Claude Comtat (claude.comtat@universite-paris-saclay.fr) and François Ramaz (francois.ramaz@espci.fr)

Novel laser sources and real-time detection for in-vivo acousto-optic imaging
Starting september/october 2024

Description: Imaging biological tissue with light is a great challenge for the detection of objects (e. g. tumors) at large depth (>cm), since multiple scattering processes prevent from a conventional imaging. The combination of ultrasound (US) and light within the medium allows to retrieve an optical information guided by the ultrasound beam, ballistic at medical application frequencies, e.g. 6MHz. Such a strategy is called Acousto-Optic Imaging (AOI), also called Ultrasound Optical Tomography (UOT), it is based on the acousto-optic effect (AO). Such an imaging is developed by many teams worldwide, in the scope to develop a bi-modal system for Medicine and Biology, in combining complementary contrast with ultrasound (e.g. conventional B-Mode imaging) and light. Many architectures have been studied up to now, but technological bottlenecks remain in order to go beyond a proof of principle. This is due to the weakness of the acousto-optic signal, itself superimposed on a strong speckle background. Among the various techniques developed at Institut Langevin, digital holography is a promising configuration for the detection, using a CMOS camera with a large number of pixels, while data treatment is optimzed with a GPU acquisition scheme. Original US-excitations are used in order to optimize the number of photons tagged by the US. Such a point will be developed by the candidate with a new fully-programmable US-system. Read more

Work location:
The work will be shared between the Institut Langevin (Paris) and the Laboratoire Charles Fabry (Palaiseau)

Contact: François Ramaz (francois.ramaz@espci.fr)

Novel laser sources and real-time detection for in-vivo acousto-optic imaging

Description: Imaging biological tissue with light is a great challenge for the detection of objects (e. g. tumors) at large depth (>cm), since multiple scattering processes prevent from a conventional imaging. The combination of ultrasound (US) and light within the medium allows to retrieve an optical information guided by the ultrasound beam, ballistic at medical application frequencies, e.g. 6MHz. Such a strategy is called Acousto-Optic Imaging (AOI), also called Ultrasound Optical Tomography (UOT), it is based on the acousto-optic effect (AO). Such an imaging is developed by many teams worldwide, in the scope to develop a bi-modal system for Medicine and Biology, in combining complementary contrast with ultrasound (e.g. conventional B-Mode imaging) and light. Many architectures have been studied up to now, but technological bottlenecks remain in order to go beyond a proof of principle. This is due to the weakness of the acousto-optic signal, itself superimposed on a strong speckle background. Among the various techniques developed at Institut Langevin, digital holography is a promising configuration for the detection, using a CMOS camera with a large number of pixels, while data treatment is optimzed with a GPU acquisition scheme. Original US-excitations are used in order to optimize the number of photons tagged by the US. Such a point will be developed by the candidate with a new fully-programmable US-system. Read more

Work location:
Institut Langevin ESPCI Paris - CNRS UMR 7587
1 rue Jussieu
75005 Paris
France

Contact: François RAMAZ (francois.ramaz@espci.fr)