Data fusion: taking into account the modulation transfer function in ARSIS-based pansharpening methods

International audienceMultispectral images provided by satellite have a poor spatial resolution while panchromatic images (PAN) exhibit a spatial resolution two or four times better. Data fusion is a mean to synthesize MS images at higher spatial resolution than original by exploiting the high spatial resolution of the PAN. This process is often called pan-sharpening. The synthesized multispectral images should be as close as possible to those that would have been acquired by the corresponding sensors if they had this high resolution. The methods based on the concept “Amélioration de la Résolution Spatiale par Injection de Structures” (ARSIS) concept are able to deliver synthesized images with good spectral quality but whose geometrical quality can still be enhanced. We propose to consider the characteristics of the sensor to improve the geometrical quality. We take explicitly into account the modulation transfer function (MTF) of the sensor in the fusion process. Though this study is limited in methods and data, we observe a better restitution of the geometry and an improvement in the majority of quality indices classically used in pan-sharpening. The communication also presents a means to assess the respect of the synthesis property from a MTF point of view

A method to better account for modulation transfer functions in ARSIS-based pansharpening methods

International audienceMultispectral (MS) images provided by Earth observation satellites have generally a poor spatial resolution while panchromatic images (PAN) exhibit a spatial resolution two or four times better. Data fusion is a means to synthesize MS images at higher spatial resolution than original by exploiting the high spatial resolution of the PAN. This process is often called pansharpening. The synthesis property states that the synthesized MS images should be as close as possible to those that would have been acquired by the corresponding sensors if they had this high resolution. The methods based on the concept Amélioration de la Résolution Spatiale par Injection de Structures (ARSIS) are able to deliver synthesized images with good spectral quality but whose geometrical quality can still be improved. We propose a more precise definition of the synthesis property in terms of geometry. Then, we present a method that takes explicitly into account the difference in modulation transfer function (MTF) between PAN and MS in the fusion process. This method is applied to an existing ARSIS-based fusion method, i.e., A trou wavelet transform-model 3. Simulated images of the sensors Pleiades and SPOT-5 are used to illustrate the performances of the approach. Although this paper is limited in methods and data, we observe a better restitution of the geometry and an improvement in all indices classically used in quality budget in pansharpening. We present also a means to assess the respect of the synthesis property from an MTF point of view

DESIRE Simulation tool to demonstrate data products for security applications

International audienceThe Simulation Tool to demonstrate Data Products for Security Applications (DESIRE) is a simulation tool aimed at demonstrating the added value of including a thermal infrared (TIR) imager within different space-borne architecture options comprising different capabilities i.e. SAR and optical. The simulator has been developed considering as end users system designers that need to assess the added value of infrared data when they are combined with other data. The DESIRE Tool development has been based on mission scenarios that address the priority areas identified in the GMES services for security e.g. Border security, Maritime Surveillance and Support to EU External Action. Particular relevant scenarios taken into account for the simulator user requirements analysis have been Oil Spill Detection, Maritime Ship Surveillance, Industrial Site Monitoring and Urban Heat Islands.The simulator is composed of an external interface capable of ingesting different input products at different processing levels (from L0 to L2, depending of the data type), a processing chain for each data type to bring the products up to L3, a co-registration module, different data combination and data fusion techniques (in order to generate merged maps or maps with information extracted from different products), and a set of modules to customize and validate the data-fusion products depending on the scenario under investigation.DESIRE has been implemented as a flexible, configurable and modular simulation tool, to be used for existing and firmly planned in-orbit capability and to combine these with real or synthetic TIR data products. DESIRE is based on the simulation framework OpenSF.The modular design of DESIRE allows the future extension of the simulator functionality with additional processing modules in order to deal with a wider range of scenarios and in-orbit architectures

Cohesin Protects Genes against γH2AX Induced by DNA Double-Strand Breaks

Chromatin undergoes major remodeling around DNA double-strand breaks (DSB) to promote repair and DNA damage response (DDR) activation. We recently reported a high-resolution map of γH2AX around multiple breaks on the human genome, using a new cell-based DSB inducible system. In an attempt to further characterize the chromatin landscape induced around DSBs, we now report the profile of SMC3, a subunit of the cohesin complex, previously characterized as required for repair by homologous recombination. We found that recruitment of cohesin is moderate and restricted to the immediate vicinity of DSBs in human cells. In addition, we show that cohesin controls γH2AX distribution within domains. Indeed, as we reported previously for transcription, cohesin binding antagonizes γH2AX spreading. Remarkably, depletion of cohesin leads to an increase of γH2AX at cohesin-bound genes, associated with a decrease in their expression level after DSB induction. We propose that, in agreement with their function in chromosome architecture, cohesin could also help to isolate active genes from some chromatin remodelling and modifications such as the ones that occur when a DSB is detected on the genome

HIV-1 Residual Viremia Correlates with Persistent T-Cell Activation in Poor Immunological Responders to Combination Antiretroviral Therapy

BACKGROUND:The clinical significance and cellular sources of residual human immunodeficiency virus type 1 (HIV-1) production despite suppressive combination antiretroviral therapy (cART) remain unclear and the effect of low-level viremia on T-cell homeostasis is still debated. METHODOLOGY/PRINCIPAL FINDINGS:We characterized the recently produced residual viruses in the plasma and short-lived blood monocytes of 23 patients with various immunological responses to sustained suppressive cART. We quantified the residual HIV-1 in the plasma below 50 copies/ml, and in the CD14(high) CD16(-) and CD16+ monocyte subsets sorted by flow cytometry, and predicted coreceptor usage by genotyping V3 env sequences. We detected residual viremia in the plasma of 8 of 10 patients with poor CD4+ T-cell reconstitution in response to cART and in only 5 of 13 patients with good CD4+ T-cell reconstitution. CXCR4-using viruses were frequent among the recently produced viruses in the plasma and in the main CD14(high) CD16(-) monocyte subset. Finally, the residual viremia was correlated with persistent CD4+ and CD8+ T-cell activation in patients with poor immune reconstitution. CONCLUSIONS:Low-level viremia could result from the release of archived viruses from cellular reservoirs and/or from ongoing virus replication in some patients. The compartmentalization of the viruses between the plasma and the blood monocytes suggests at least two origins of residual virus production during effective cART. CXCR4-using viruses might be produced preferentially in patients on cART. Our results also suggest that low-level HIV-1 production in some patients may contribute to persistent immune dysfunction despite cART

Fusion de données : prise en compte des caractéristiques liées à l'imageur lors de la synthèse d'images multispectrales à haute résolution spatiale

Maître de thèse : Philippe BlancEarth observation satellites (Quickbird, Ikonos, SPOT-5, PLÉIADES) provide two types of images: the panchromatic image at high spatial resolution with a poor spectral resolution, and the multispectral image with a good spectral resolution but at a spatial resolution 2 or 4 times lower than each of the panchromatic. Image fusion methods for this to types of images already exist, whereas we still can add/provide amelioration that aim to improve the quality of synthesized images. My work look for improving the quality of synthesized images thanks to a better consideration of the sensor characteristics like the Modulation Function Transfer (MTF), and the sampling. The work on the evaluation of the effect of the aliasing of the MS on the synthesized MS show that the suppression of aliasing suppress visual artifact but it reveal that it not significant with actual quality analysis. MTF express the sensor capacities to represent a contrast in function of the spatial frequency. Based on an existing method we proposed two new methods that allowed to better take into account the MTF difference that exist between PAN and MS images. Two new methods had been proposed that are based on existing method and allowed to better take into which take into account the difference of MTF between PAN and MS images.Les satellites d'observation de la Terre (Quickbird, Ikonos, SPOT-5, PLÉIADES) fournissent des images de deux types : soit une image panchromatique à haute résolution spatiale mais basse résolution spectrale, soit une image multispectrale dont la résolution spatiale est inférieure d'un rapport 2 ou 4, mais avec une bonne résolution spectrale. Des méthodes permettant la fusion de ces deux types d'images existent, cependant il est encore possible d'améliorer la qualité des images synthétisées. Nos travaux visent à améliorer la qualité des images synthétisées par une meilleure prise en compte des caractéristiques de l'imageur comme ; la Fonction de Transfert de Modulation (FTM) et l'échantillonnage. Les travaux que nous avons menés sur l'impact du repliement de spectre présent dans les images MS ont mis en évidence que l'absence de repliement permet la suppression des artefacts visuels importants, mais les outils usuels d'évaluation de la qualité des images de fusion ne permettent pas la quantification des performances. La FTM caractérise la capacité de l'instrument à représenter un contraste en fonction de la fréquence spatiale. Celle-ci diffère entre les images PAN et MS. Nous avons proposé à partir de méthodes existantes, deux méthodes de fusion permettant de mieux prendre en compte la FTM et ainsi d'améliorer la qualité et les caractéristiques de l'image synthétisée

Fusion de données (prise en compte des caractéristiques liées à l'imageur lors de la synthèse d'images multispectrales à haute résolution spatiale)

PARIS-MINES ParisTech (751062310) / SudocSudocFranceF

Feline infectious peritonitis, proteins of plasma and ascitic fluid

Electrophoreses of sera, plasma and ascitic fluids of cats with natural or experimental infectious peritonitis show important modifications. Special stainings of electrophoreses and chromatographic and immunoelectrophoretic technics characterized some of the modified proteins. In the experimental disease, fibrinogen, haptoglobin, transferrin, and probably orosomucoid are increased; in the natural disease, in addition to these modifications, the y-globulins are strongly increased; the immunoglobulins found in the often abundant ascitic fluid belong to the IgG class. Increased proteins such as fibrinogen, haptoglobin and orosomucoid and decreased albumin are aspecific aspects of inflammatory processes, whereas hyperganimaglobulinemia appears in the course of immunological response. The rapid evolution of the experimental disease explains the fact that immunoglobulins do not increase