Search results for " Image processing"
showing 10 items of 2323 documents
In Vitro Arrhythmia Generation by Mild Hypothermia - a Pitchfork Bifurcation Type Process
2015
International audience; The neurological damage after cardiac arrest (CA) constitutes a big challenge of hospital discharge. The therapeutic hypothermia (34°C-32°C) has shown its benefit to reduce cerebral oxygen demand and improve neurological outcomes after the cardiac arrest. However, it can have many adverse effects, among them the cardiac arrhythmia generation represents an important part (up to 34%, according different clinical studies). Monolayer cardiac culture is prepared with cardiomyocytes from new-born rat directly on the multi-electrodes array, which allows acquiring the extracellular potential of the culture. The temperature range is 37°C - 30°C - 37°C, representing the coolin…
Détection d'Anomalie dans les Signaux Physiologiques
2015
International audience; Les signaux physiologiques sont des séries temporelles riches en informations. Analyser ces signaux pour extraire ces informations, pour établir un diagnostic ou encore pour prédire une évolution, nécessite des outils performants et adaptés à leurs caractéristiques intrinsèques. En effet le comportement d'un système biologique dépend des variations de très nombreux paramètres, ce qui le rend alors presque imprévisible. Les méthodes issues de la théorie du chaos et de la dynamique non linéaire apportent des éléments qui permettent de comprendre ce type de comportements, et d'établir ainsi un lien qualitatif avec des modèles mathématiques bio-inspirés ou phénoménologiq…
Retrievals of soil moisture and optical depth from CAROLS
2011
International audience; We propose in this paper to evaluate a method to retrieve soil moisture (SM) and vegetation optical thickness, in areas of unknown roughness and unknown vegetation water content in view of operational applications, by using airborne Tb measurements acquired in South-West of France. Results are compared to in situ measurements, manual and automatic ones included in SMOSmania network, in the South-West of France.
Translucent medium
2013
8 pages; article in McGraw-Hill Science & Technology Encyclopedia; International audience; A medium allowing light to pass through partially or diffusely. An object cannot be seen clearly through translucent matter. In the most accepted meaning, translucency is used to describe a medium transmitting most of the light but scattering it more or less so that objects seen through it are blurry with soft contours and without details. The closer the object is to the medium the sharper its image through it. There are many examples of such media among natural or manufactured artifacts, including wax paper, milky water, colloidal and hydrogel materials, aerogels, smoke, fog, clouds, optical ceramics…
A Study on the Impact of Spectral Characteristics of Filters on Multispectral Image Acquisition
2013
International audience; In every aspect, filter design plays an important role in an image acquisition system based on a single image sensor and a colour filter array (CFA) mounted onto the sensor. Complementary CFAs are used by some colour cameras in the interest of higher sensitivity, which motivated us to employ filters of wide pass bands in the effort to adapt CFA for multispectral image acquisition. In this context, filter design has an effect on the accuracy of spectrum reconstruction in addition to other aspects. The results show that wider bandwidths in general result in more faithful spectrum reconstruction and higher signal-to-noise performance.
Intérêt de l’analyse multispectrale des images endoscopiques de la muqueuse gastrique pour reconnaitre la gastrite inflammatoire et ses différents…
2014
International audience
Mixed Driven Refinement Design of Multidimensional Models based on Agglomerative Hierarchical Clustering
2015
20 pages; International audience; Data warehouses (DW) and OLAP systems are business intelligence technologies allowing the on-line analysis of huge volume of data according to users' needs. The success of DW projects essentially depends on the design phase where functional requirements meet data sources (mixed design methodology) (Phipps and Davis, 2002). However, when dealing with complex applications existing design methodologies seem inefficient since decision-makers define functional requirements that cannot be deduced from data sources (data driven approach) and/or they have not sufficient application domain knowledge (user driven approach) (Sautot et al., 2014b). Therefore, in this p…
Système de prise d'images haute résolution pour l'analyse de projection de particules : application à l'épandage centrifuge d'engrais
2002
This paper describes the design of a high resolution low cost imaging system for the analysis of high speed particle projection. This system, based on a camera and a set of flashes, is used to characterize the centrifugal spreading of fertilizer particles ejected at speeds of environ 30 m s. Multiexposure images collected with the camera installed perpendicular to the output flow of granules are analysed to estimate the trajectories of the fertilizer granules. Very good results are obtained with the Markov random fields method, in comparison with others.
Capteurs et images aériennes pour l’évaluation du peuplement de mauvaises herbes
2013
AIRINOV is specialized in use of UAV for precision agriculture. Thanks to a high spatial resolution up to 1.5 cm/pixel in RGB images, discrimination between vegetation (crop row, weed) and soil can be done. Variability can be detected in weed density inside the whole field. The detection of weeds in the inter-row of hoed row crops was tested on RGB images. The methodology developed is based on Hough transform, and is composed of three main steps: image segmentation, soil/vegetation discrimination and crop rows localization. First results are promising but need complementary measures for validation.
Mesure de netteté basée sur les descripteurs généralisés de Fourier appliquée à la reconstruction 3D par Shape from Focus
2013
National audience; L'étape principale de la méthode de reconstruction 3D " Shape from Focus " est l'utilisation d'un opérateur de mesure de netteté de chaque pixel de la séquence d'image. Le choix de l'opérateur de mesure de netteté est une étape cruciale pour une reconstruction 3D de qualité. La précision de la mesure de netteté dépend de la taille du voisinage autour du pixel choisi et de la présence ou non de bruit additif dans la séquence d'images. Dans cet article, nous présentons deux nouveaux opérateurs de mesure de netteté basés sur les Descripteurs Généralisés de Fourier. Une nouvelle étude comparative des différents opérateurs est présentée. Cette comparaison est basée sur un plan…