27 research outputs found

    Heterogeneous Multidimensional Data Deblurring

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    International audienceWe present a new scheme for deconvolution of heterogeneous multidimensional data (\eg spatio-temporal or spatio-spectral). It is derived, in a very general way, following an inverse problem approach. This method exploits the continuity of both object and PSF along the different dimensions to elaborate separable constraints. This improves the effectiveness and the robustness of the deconvolution technique. We demonstrate these improvements by processing real X-ray video sequences (x,y,t)(x,y,t) and astronomical multi-spectral images (x,y,λ)(x,y,\lambda)

    Ramial wood amendments (Piliostigma reticulatum) mitigate degradation of tropical soils but do not replenish nutrient exports

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    Restoring degraded soils to support food production is a major challenge for West African smallholders who have developed local innovations to counter further degradation. The objective of this study was to evaluate a local farmer's technique that uses ramial wood (RW) as soil amendment (Piliostigma reticulatum shrub). Three treatments were applied in an experimental plot in Burkina Faso: control (no amendment), low RW (3 Mg fresh mass·ha−1·yr−1), and high RW (12 Mg fresh mass·ha−1·yr−1). RW was chipped to <5‐cm pieces and either buried or mulched. Topsoil carbon (C), nitrogen (N), and phosphorus (P) in control and low‐RW treatments declined after 7 years of continuous sorghum cultivation. Use of high‐RW amendment stabilized soil C content while N and P declined, thus not replenishing nutrient exports. Net contribution to soil C in the layer measuring 0–15 cm was 15% of the applied C in the high‐RW amendments. Although biomass and grain yields were higher in high‐RW treatments, crop productivity declined throughout the experiment for all treatments. Termite casts on RW treatments evidenced the potential role of wood‐foraging termites in diluting the impact of RW on soil fertility build‐up and soil water content. We conclude that mitigating soil degradation under semiarid conditions in Burkina Faso would require large amounts of woody amendments, particularly if the level of termite activity is high. Additional nutrient sources would be needed to compensate for removal in exported products so that biomass and grain production can be stabilized or increased.EstaciĂłn Experimental Agropecuaria BarilocheFil: FĂ©lix, Georges F. Wageningen University. Farming Systems Ecology; HolandaFil: Clermont-Dauphin, Cathy. Montpellier SupAgro- Centre de CoopĂ©ration Internationale en Recherche Agronomique pour le DĂ©veloppement-Institut National de la Recherche Agronomique. Eco&Sols; FranciaFil: Hien, Edmond. Laboratoire Mixte International. Intensification Ecologique des Sols CultivĂ©s en Afrique de l'Ouest; Burkina FasoFil: Groot, Jeroen C.J. Wageningen University. Farming Systems Ecology; HolandaFil: Penche, Aurelien. Laboratoire Mixte International. Intensification Ecologique des Sols CultivĂ©s en Afrique de l'Ouest; Burkina FasoFil: BarthĂšs, Bernard G. Universidad Montpellier; FranciaFil: Manlay, RaphaĂ«l J. AgroParisTech; FranciaFil: Tittonell, Pablo Adrian. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Agropecuaria Bariloche; ArgentinaFil: Cournac, Laurent. Montpellier SupAgro- Centre de CoopĂ©ration Internationale en Recherche Agronomique pour le DĂ©veloppement-Institut National de la Recherche Agronomique. Eco&Sols; Franci

    Recherche d'indices prédictifs de succÚs de la resynchronisation cardiaque (à partir d'une série prospective de 83 patients)

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    LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

    BLIND DECONVOLUTION OF VIDEO SEQUENCES

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    International audienceWe present a new blind deconvolution method for video sequence. It is derived following an inverse problem approach in a Bayesian framework. This method exploits the temporal continuity of both object and PSF. Combined with edge-preserving spatial regularization, a temporal regularization constrains the blind deconvolution problem, improving its effectiveness and its robustness. We demonstrate these improvements by processing various real video sequences obtained by different imaging techniques

    Blind deconvolution of video sequences

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    ProblĂšme traitĂ© - Nous proposons ici une mĂ©thode pour la dĂ©convolution aveugle de sĂ©quences d'images bio-mĂ©dicales. OriginalitĂ© - A notre connaissance peu de recherches ont Ă©tĂ© accomplies dans le domaine de la dĂ©convolution aveugle de donnĂ©es multi- dimmensionnelles hĂ©tĂ©rogĂšnes, c'est-Ă -dire dont les dimensions n'ont pas toutes les mĂȘme significations physiques, comme les sĂ©quences vidĂ©o. Dans une approche maximum a posteriori (MAP), nous proposons une rĂ©gularisation sĂ©parable pour prendre en compte les corrĂ©lations suivants les diffĂ©rentes dimensions tant pour la PSF que pour l'objet. RĂ©sultats - Cette mĂ©thode a Ă©tĂ© testĂ©e avec succĂšs dans diffĂ©rentes applications bio-mĂ©dicale: la coronarographie, la microscopie confocale et la microscopie classique

    Déconvolution aveugle de séquences vidéo

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    National audienceNous proposons ici une méthode pour la déconvolution aveugle de séquences d'images. Dans une approche maximum a posteriori (MAP), nous proposons une régularisation séparable pour prendre en compte les corrélations suivants les différentes dimensions tant pour la PSF que pour l'objet. La combinaison d'une régularisation spatiale préservant les bords avec une regularisation temporelle sur l'objet permet de contraindre efficacement le problÚme de la déconvolution aveugle. Cela aboutit à une restauration importante des détails de l'objet observé. Cette méthode a été testée avec succÚs pour différentes applications bio-médicales : la coronarographie, la microscopie confocale et la microscopie classique
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