Influence of the three-dimensional effects on the simulation of landscapes in thermal infrared

International audienceThe paper deals with the modelling of landscapes for the simulation of very high spatial resolution images in the thermal infrared range, from 3 to 14 μm. It focuses on the influence of the 3-D effects on the simulation. The major relevant physical processes are described. Examples are made, comparing simulations obtained with 2-D and 3-D representation of the landscape. They help in classifying the relative influence of each process. The necessity to take into account a 3-D landscape representation for the simulation of very high spatial resolution images in the infrared range is also demonstrated

Specifications and conceptual architecture of a thermal infrared simulator of landscapes

International audienceThis paper deals with the simulation of very high spatial resolution images in the thermal infrared range, from 3 to 14 m. It focuses on the conceptual architecture of a simulator of 3-D landscapes; its specifications are described and discussed. A new methodology is proposed for the simulation to best reproduce the properties of the infrared imagery. Particularly, this methodology enables a very accurate simulation of the signal coming from each object constituting the landscape. The interactions between the radiations and objects and between objects themselves are considered. Their changes in time, and the recent past of the temperature and the humidity for each object, are taken into account. To reproduce these physical phenomena, the computation is performed on elements, which are defined as homogeneous entities with respect to the physical processes. This concept of element leads to a new methodology in design and realization of simulators. It permits to reproduce efficiently the behavior of the landscape in this spectral range at very high spatial resolution

Outdoor Scene Synthesis in the Infrared Range for Remote Sensing Applications

International audienceThis paper deals with a method of representation of landscape for the simulation of the behavior of an outdoor scene in the thermal infrared range, from 3 to 14 μm. The scene and objects are modeled in 3-D at very high spatial resolution of half a meter or so. The mesh is adapted to reproduce all the physical phenomena and their variations, according to their relative importance. The classical facet is no longer appropriate. A new quantity is introduced: the element. The element is defined as a part of an object. It is homogeneous with respect to material constitution and energy flux balance at a given instant. The mesh representing the scene is made of the union of the elements for the period of simulation of the temperature. All computations of fluxes and temperature are made on this mesh. Sufficient accuracy can be achieved by considering the most important physical phenomena to generate the elements. Shadow effect is the most important one. Influences of other phenomena are modeled by the mean of texture synthesis. In this paper, the method to define and generate elements is exposed, and an example is given, showing the efficiency of such a method to predict surface temperature, and afterward the irradiance of the scene

Simulation d'images dans l'infrarouge thermique par une approche synthétique : spécifications et architecture fonctionnelle

International audienceon présente les spécifications et l'architecture fonctionnelle d'un simulateur de scènes dans l'infrarouge thermique pour des longueurs d'onde variant de 3 14 micron. Ce simulateur doit être capable de générer des scènes avec une trés haute résolution spatiale et de gérer l'ensemble des interactions entre les objets composant le paysage. Les phénomènes physiques sont brièvement rappelés ; une méthodologie originale de simulation basée sur la gestion d'entités homogènes spatialement et temporellement vis à vis des processus physiques est proposée. Elle permet de traduire efficacement l'histoire récente de la scène, toujours nécessaire la simulation d'une image infrarouge

OSIrIS: a physically based simulation tool to improve training in thermal infrared remote sensing over urban areas at high spatial resolution

International audienceThis paper describes an infrared image simulator for remote sensing applications, called OSIrIS (outdoor scene and infrared image simulation). It has been developed partly for training and reproduces with great details the physical phenomena that play a major role in complex urban environment. OSIrIS performs a synthesis of scene based on a 3-D description of the landscape with a high spatial resolution (0.5 – 10 m). The physical processes are briefly described and their importance with respect to the objectives are discussed. Thermal emission depends on temperature and generally dominates the signal. Temperature is governed by heat equation and is solved by the means of boundary conditions such as in-depth temperature and flux balance at surface. Main parameters are solar and atmospheric radiations, wind, heat conduction and changes in humidity. An innovative approach was developed to take into account variations in time of the interactions between the landscape and the physical processes. OSIrIS aims at simulating situations that are encountered in reality. It enables users self-formation, helping them understanding changes in image radiance as a function of the input parameters and their own simulation requirements. Examples are given that illustrate specific aspects of infrared images

Interleukin-18 produced by bone marrow- derived stromal cells supports T-cell acute leukaemia progression

International audienceDevelopment of novel therapies is critical for T-cell acute leukae-mia (T-ALL). Here, we investigated the effect of inhibiting the MAPK/MEK/ERK pathway on T-ALL cell growth. Unexpectedly, MEK inhibitors (MEKi) enhanced growth of 70% of human T-ALL cell samples cultured on stromal cells independently of NOTCH activa-tion and maintained their ability to propagate in vivo. Similar results were obtained when T-ALL cells were cultured with ERK1/ 2-knockdown stromal cells or with conditioned medium from MEKi-treated stromal cells. Microarray analysis identified interleu-kin 18 (IL-18) as transcriptionally up-regulated in MEKi-treated MS5 cells. Recombinant IL-18 promoted T-ALL growth in vitro, whereas the loss of function of IL-18 receptor in T-ALL blast cells decreased blast proliferation in vitro and in NSG mice. The NFKB pathway that is downstream to IL-18R was activated by IL-18 in blast cells. IL-18 circulating levels were increased in T-ALL-xeno-grafted mice and also in T-ALL patients in comparison with controls. This study uncovers a novel role of the pro-inflammatory cytokine IL-18 and outlines the microenvironment involvement in human T-ALL development

Synthèse de paysages dans l'infrarouge thermique pour la simulation d'images de télédétection

Companies have already developed simulators of the image acquisition system in the thermal infrared range. Operating these simulators requires the knowledge of numerous parameters, including the landscape to observe. This landscape has to be simulated, a great difficulty because of the complexity of its behaviour. It follows that few simulators of landscapes were developed. This thesis palliates this shortcoming. A method is proposed that simulates images having high spatial resolution in the infrared range. A simulator has been designed and developed. Using a thermal and spectral modelling of the behaviour of the landscape, a classification of the different physical phenomena intervening in the signal was made. A very high accuracy in simulation is obtained by the means of the analysis and the computation of physical phenomena occurring at small scale (heat conduction, wind flow disturbance,...) and in three dimensions (shadows, reflections,...). A fine modelling of such processes is required. The originality of the thesis is the design of a method adapted to the synthesis of image in the infrared range. The method is based on radiosity. The landscape is modelled by the means of elements, that are entities permitting the prediction of the signal coming from the landscape. These elements are consistent with computational resource requirements: computation time and memory performance. They come from the concatenation of all constraints due to the geometry of the objects, their constitution (material), and the impact of the evolution of all physical phenomena in the landscape behaviour. These elements are a volume and temporal extension of facets, entity usually used in image synthesis for shorter wavelengths. Images obtained using such elements and the simulator are presented in the thesis.Dans l'infrarouge thermique, des simulateurs de systèmes d'acquisition d'images existent déjà chez les industriels. Leur fonctionnement nécessite la connaissance de nombreux paramètres, dont celle du paysage à observer. Or, ce paysage doit lui-même être simulé. Du fait de la complexité de son comportement, peu de simulateurs de paysages ont été développés. Cette thèse tente de pallier à ce manque, en proposant une méthode de simulation adaptée à l'imagerie à haute résolution spatiale dans l'infrarouge thermique. Un simulateur a été conçu et développé. A l'aide d'une modélisation physique du comportement thermique et spectral du paysage, une classification des contributions des différents phénomènes physiques a pu être établie. Une simulation autorisant un haut degré de détails passe notamment par l'analyse et la prise en compte des phénomènes physiques à petite échelle (conduction, perturbations de l'écoulement du vent, ...) et à trois dimensions (ombrage, réflexions, ...) et implique la modélisation fine de ces phénomènes. L'originalité de la thèse réside dans la création d'une méthode de simulation, basée sur la radiosité, et adaptée à la synthèse d'images dans l'infrarouge thermique. Le paysage est modélisé à l'aide d'entités, les éléments, permettant de prédire précisément le signal provenant du paysage. Ces éléments sont compatibles avec les exigences matérielles informatiques qui imposent des limitations de temps de calcul et de ressources mémoires. Ils résultent de la concaténation des contraintes imposées par la géométrie des objets, par leur constitution (matériaux), et par la prise en compte de l'évolution temporelle des différents phénomènes physiques qui régissent le comportement du paysage. Ces éléments constituent une extension volumique et temporelle des facettes, entités communément utilisées pour la synthèse d'images dans les courtes longueurs d'onde. Des images obtenues en utilisant les éléments et le simulateur développé sont présentées dans la thèse

Synthèse de paysages dans l'infrarouge thermique pour la simulation d'images de télédétection

Cette thèse propose une méthode de simulation adaptée à l'imagerie à haute résolution spatiale dans l'infrarouge thermique. Un simulateur a été conçu et développé. Une simulation fine des comportements thermique et spectral passe par la prise en compte des phénomènes physiques à petite échelle et à trois dimensions. L'originalité de la thèse réside dans la création d'une méthode de simulation basée sur la radiosité. Le paysage est modélisé à l'aide d'éléments, entités permettant de prédire précisément le signal. Ces éléments sont compatibles avec les exigences matérielles informatiques qui imposent des limitations de temps de calcul et de ressources mémoires. Ils résultent de la concaténation des contraintes imposées par la géométrie des objets, leur constitution (matériaux), et la prise en compte de l'évolution temporelle des différents phénomènes physiques. Il s'agit d'une extension volumique et temporelle des facettes utilisées en synthèse d'images courtes longueurs d'onde.This thesis proposes a method that simulates images having high spatial resolution in the infrared range. A simulator has been designed and developed. A very high accuracy, in thermal and spectral modelling of the behaviour of the landscape, is obtained by the means of the analysis and the computation of physical phenomena occurring at small scale and in three dimensions. The originality of the thesis is the design of a method based on radiosity. The landscape is modelled by the means of elements, that are entities permitting an accurate prediction of the signal. These elements are consistent with computational resource requirements: computation time and memory performance. They come from the concatenation of all constraints due to the geometry of the objects, their constitution (material), and the impact of the evolution of all physical phenomena. These elements are a volume and temporal extension of facets, entity usually used in image synthesis for shorter wavelengths.NICE-BU Sciences (060882101) / SudocSOPHIA ANTIPOLIS-Mines ParisTech (061522302) / SudocSudocFranceF

Mapping offshore wind resources : synergetic potential of SAR and scattometer data.

International audienceAn accurate evaluation of the wind potential is needed to assess the economic reliability of an offshore wind project and to site wind farms, which need high-spatial-resolution wind fields with high repetitiveness. A measurement campaign is highly expensive, and the in situ data obtained are insufficient: the data time series are too short, and only defined at a single location. Moreover, the wind-flow models usually used, are unable to accurately extrapolate the data from the mast over the entire area of interest. Fortunately, wind fields at sea can be measured by active spaceborne sensors, such as synthetic aperture radar (SAR) and scatterometer sensors. This paper aims at evaluating the adequacy of wind data from space to the data requirements of the offshore wind industry. The different types of data available from space are described. The temporal sampling of the satellite data is evaluated compared to user needs. The adequacy of this set of information for Weibull-distribution estimation is demonstrated. A study area has been selected to illustrate the approach, namely the French Gulf of Lion area

Applicability of superresolution to the vegetation sensor

International audienc