Motion tubes for the representation of images sequences

International audienceIn this paper, we introduce a novel way to represent an image sequence, which naturally exhibits the temporal persistence of the textures. Standardized representations have been thoroughly optimized, and getting significant improvements has become more and more difficult. As an alternative, Analysis-Synthesis (AS) coders have focused on the use of texture within a video coder. We introduce here a new AS representation of image sequences that remains close to the classic block-based representation. By tracking textures throughout the sequence, we propose to reconstruct it from a set of moving textures which we call motion tubes. A new motion model is then proposed, which allows for motion field continuities and discontinuities, by hybridizing Block Matching and a low-computational mesh-based representation. Finally, we propose a bi-predictional framework for motion tubes management

Estimation de mouvement par maillages et lignes de rupture pour le codage de séquences vidéo

Dans le cadre de l'analyse et du codage de séquences vidéo, nous présentons ici une nouvelle structure de maillage pour la représentation du mouvement dans les zones d'occlutation. Nous proposons l'utilisation de la notion de lignes de rupture qui permet de représenter une discontinuité dans le champ de mouvement and nous créons un maillage non-manifold permettant d'estimer le mouvement dans les zones d'occultations sans entraîner de dégénérations des mailles. Le maillage non-manifold représente de façon satisfaisante les discontinuités du mouvement introduites par les objets en mouvement et améliore l'estimation du mouvement dans les zones d'occultation. Les résultats montrent une meilleure prédiction de la texture dans ces zones, améliorant ainsi les performances de codage

Codage video scalable par maillages et ondelettes t+2D

The subject of this PhD thesis is Scalable Video Coding Using Deformable Meshes and t+2D Wavelets TransformCette thèse s'inscrit dans le cadre de la transmission de données vidéo sur réseaux. L'objectif de notre étude est d'étudier des technologies innovantes permettant d'offrir un codage vidéo hautement scalable et compétitif en terme de compression avec les standards de codage vidéo actuels non scalables. Pour cela, nous utilisons un schéma de codage vidéo basé sur une approche analyse-synthèse qui utilise une représentation du mouvement par maillages et un codage par ondelettes t+2D. La première partie de notre étude s'intéresse à l'exploitation du mouvement dans la transformée en ondelettes temporelles et à la définition des trajectoires de mouvement le long desquelles est appliquée la transformation temporelle. La deuxième partie de notre étude propose une amélioration de ce schéma en gérant le problème des occlusions engendrés par les discontinuités du mouvement

Codage vidéo scalable par maillages et ondelettes t+2D

Cette thèse s'incrit dans le cadre de la transmission de données vidéo sur réseaux. L'objectif de notre étude est d'étudier des technologies innovantes permettant d'offrir un codage vidéo hautement scalable et compétitif en terme de compression avec les standards de codage vidéo actuels non scalables. Pour cela, nous utilisons un schéma de codage vidéo basé sur une approche analyse-synthèse qui utilise une représentation du mouvement par maillages et un codage par ondelettes t+2D. La première partie de notre étude s'intéresse à l'exploitation du mouvement dans la transformée en ondelettes temporelles et à la définition des trajectoires de mouvement le long desquelles est appliquée la transformation temporelle. La deuxième partie de notre étude propose une amélioration de ce schéma en gérant le problème des occlusions engendrés par les discontinuités du mouvement.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Fully Scalable Object Based Video Coder Based on Analysis-Synthesis Scheme

In this paper we present a novel object based video coder. This coder is based on an analysis-synthesis approach which allows for decoupling shape, motion and texture informations. These informations are then coded using wavelets decomposition and progressive coding allowing to have full scalability (object, SNR, temporal, and bitstream scalabilities). Experimental results show the benefits of proposed scheme providing performances close to state of the art video coders while providing scalability

Nanoprecipitation of Biocompatible Poly(malic acid) Derivative, Its Ability to Encapsulate a Molecular Photothermal Agent and Photothermal Properties of the Resulting Nanoparticles

International audienceBiocompatible nanoparticles (NPs) of hydrophobic poly(benzyl malate) (PMLABe) were prepared by nanoprecipitation. The influence of nanoprecipitation parameters (initial PMLABe, addition rate, organic solvent/water ratio and stirring speed) were studied to optimize the resulting formulations in terms of hydrodynamic diameter (Dh) and dispersity (PDI). PMLABe NPs with a Dh of 160 nm and a PDI of 0.11 were isolated using the optimized nanoprecipitation conditions. A hydrophobic near infra-red (NIR) photothermally active nickel-bis(dithiolene) complex (Ni8C12) was then encapsulated into PMLABe NPs using the optimized nanoprecipitation conditions. The size and encapsulation efficiency of the NPs were measured, revealing that up to 50 weight percent (wt%) of Ni8C12 complex can efficiently be encapsulated with a slight increase in Dh of the corresponding Ni8C12-loaded NPs. Moreover, we have shown that NP encapsulating Ni8C12 were stable under storage conditions (4 °C) for at least 10 days. Finally, the photothermal properties of Ni8C12-loaded NPs were evaluated and a high photothermal efficiency (62.7 ± 6.0%) waswas measured with NPs incorporating 10 wt% of the Ni8C12 complex

Investigations of the Photothermal Properties of a Series of Molecular Gold-bis(dithiolene) Complexes Absorbing in the NIR-III Region

International audienceThe photothermal properties of a series of neutral radical gold-bis(dithiolene) complexes absorbing in the near-infrared-III window (1550 - 1870 nm) have been investigated. This class of complexes was found to be good photothermal agents (PTAs) in toluene under 1600 nm laser irradiation with photothermal efficiencies around 40 and 60% depending on the nature of the dithiolene ligand. To the best of our knowledge, these complexes are the first small molecular photothermal agents to absorb so far into the near infrared. To test their applicability in water, these hydrophobic complexes have been encapsulated into nanoparticles constituted by amphiphilic block-copolymers. Stable suspensions of polymeric nanoparticles (NPs) encapsulating the gold-bis(dithiolene) complexes have been prepared which show a diameter around 100 nm. The encapsulation rate was found to be strongly dependent on the nature of the dithiolene ligands. The photothermal properties of the aqueous suspensions containing gold-bis(dithiolene) complexes were then studied under 1600 nm laser irradiation. These studies demonstrate that water has strong photothermal activity in the NIR-III region that, cannot be overcome even with the addition of gold complexes displaying good photothermal properties

Folate-equipped pegylated archaeal lipid derivatives: synthesis and transfection properties

International audienc

Biocompatible nanoparticles containing hydrophobic nickel-bis(dithiolene) complexes for NIR-mediated doxorubicin release and photothermal therapy

International audienceBiocompatible nanoparticles (NPs) constituted by amphiphilic poly(ethylene glycol)-block-poly(benzyl malate), PEG-b-PMLABe, have been designed for site-specific PhotoThermal Controlled Release (PTCR) of drugs thanks to the presence of a near infra-red (NIR) photothermally active nickel-bis(dithiolene) complex in the inner core of the NPs, together with doxorubicin (Dox). A nanoprecipitation technique was used to prepare well-defined nickel-bis(dithiolene) and nickel-bis(dithiolene)/Dox loaded NPs, which were characterized by dynamic light scattering (DLS), zeta-potential measurements and Transmission Electron Microscopy (TEM). We have shown that the Dox release was effectively controlled by NIR irradiation (long or pulsed NIR laser irradiation). Cytotoxicity experiments on HeLa and MDA-MB-231 cells have shown that the incorporation of more than 10 w% of nickel-bis(dithiolene) complexes does not increase the intrinsic toxicity of the polymer nanoparticles. Finally, the viability of MDA-MB-231 cells was assessed after their incubation, for 24 hours, with empty NPs, Ni4C(12) loaded NPs, Dox loaded NPs or Ni4C(12)/Dox loaded NPs, without or with NIR irradiation. Above all, the results have highlighted that the Ni4C(12) loaded NPs after 5 min NIR laser irradiation can induce strong cell death up to 80% at 50 g mL(-1). These results demonstrate that these NPs are good candidates for photothermal therapy

Liposomes Containing Nickel-Bis(dithiolene) Complexes for Photothermal Theranostics

International audienceNew thermosensitive liposomes with a phase transition at 42 °C, containing nickel-bis(dithiolene) complexes as efficient and stable photothermal agents, have been formulated and characterized. These liposomes are highly stable and keep their contents at 37 °C for more than 30 days. On the contrary, the mild hyperthermia generated by the nickel-bis(dithiolene) complex under 940 nm NIR irradiation allows for the fine controlled release of the liposome contents, making such liposomes highly suitable for on-demand drug delivery in the human body under NIR laser irradiation. These liposomes can also be directly used, as shown here, as nanoagents for photothermal therapy. In fact, strong cell death can be generated under laser irradiation in the presence of these photothermally active nanocargos containing less than 10% w/w of metal complex. We also demonstrate, for the first time, that nickel-bis(dithiolene) complexes are good photoacoustic agents, generating easily detectable ultrasonic signals directly proportional to the concentration of complexes and the used laser power