Un modèle neuronal pour la reconnaissance d'objets

- Nous présentons une architecture neuronale capable d'apprendre et de reconnaître des formes à partir d'une caméra CCD disposée sur un robot mobile. Les principes utilisés pour construire l'architecture s'appuie sur des données neurobiologiques notamment sur le système visuel des mammifères. Ces mécanismes nous ont déjà permis de réaliser, avec succès, un système de reconnaissance de lieux pour la navigation de robot autonome. Notre travail reprend les bases de ce système, fondé sur l'extraction de vues locales et de position relative des vues, et l'étend à la reconnaissance d'objets dans les images. Une partie de l'architecture développée intervient pour corriger les translations des objets dans l'image, elle donne en outre une mesure de confiance (point de vue moteur) sur la reconnaissance, qui vient compléter l'information donnée par la sortie reconnaissance du système

Use of CCD to Detect Terrestrial Cosmic Rays at Ground Level: Altitude vs. Underground Experiments, Modeling and Numerical Monte Carlo Simulation

International audienceIn this work, we used a commercial charge-coupled device (CCD) camera to detect and monitor terrestrial cosmic rays at ground level. Multi-site characterization has been performed at sea level (Marseille), underground (Modane Underground Laboratory) and at mountain altitude (Aiguille du Midi-Chamonix Mont-Blanc at +3,780 m of altitude) to separate the atmospheric and alpha particle emitter's contributions in the CCD response. An additional experiment at avionics altitude during a long-haul flight has been also conducted. Experiment results demonstrate the importance of the alpha contamination in the CCD response at ground level and its sensitivity to charged particles. Experimental data as a function of CCD orientation also suggests an anisotropy of the particle flux for which the device is sensitive. A complete computational modeling of the CCD imager has been conducted, based on a simplified 3D CCD architecture deduced from a reverse engineering study using electron microscopy and physico-chemical analysis. Monte Carlo simulations evidence the major contribution of low energy (below a few MeV) protons and muons in the CCD response. Comparison between experiments and simulation shows a good agreement at ground level, fully validated at avionics altitudes with a much higher particle flux and a different particle cocktail composition

Analyse d'images : Filtrage et segmentation

Ouvrage publié avec l'aide du Ministère des affaires étrangères, direction de la coopération scientifique et technique. AVERTISSEMENT Le livre publié en 1995 chez MASSON (EAN13 : 9782225849237) est épuisé. Cette version pdf est une version élaborée à partie de la version préliminaire transmise à l'éditeur. La mise en page est légèrement différente de celle du livre. Malheureusement quelques figures de l'annexe C ont été perdues.International audienceL'analyse d'image touche à l'heure actuelle de nombreux domaines, avec des objectifs aussi variés que l'aide au diagnostic pour les images médicales, la vision artificielle en robotique ou l'analyse des ressources terrestres à partir des images prises par satellite. Le but du traitement de ces images est à la fois simple dans son concept et difficile dans sa réalisation. Simple en effet, puisqu'il s'agit de reconnaître des objets que notre système visuel perçoit rapidement, du moins pour la majorité d'entre eux. Difficile cependant, car dans la grande quantité d'informations contenues dans l'image, il faut extraire des éléments pertinents pour l'application visée et ceci indépendamment de la qualité de l'image. L'analyse d'image s'est donc dotée d'outils et de méthodes puissants issus de domaines aussi variés que les mathématiques, le traitement du signal, ou l'informatique. Cet ouvrage présente un des aspects les plus importants du traitement des images : la " segmentation ". Il récapitule d'abord les grandeurs observables et calculables sur une image et les algorithmes de manipulation des structures de données associées. Il détaille ensuite les traitements préliminaires, tels le filtrage du bruit et les deux types d'approche de la segmentation, l'extraction des contours et celle des régions. Chacune fait l'objet d'une étude théorique et de nombreux résultats illustrent les performances. Une des originalités de l'ouvrage est l'étude comparative des différentes techniques appliquées sur un même corpus d'images réelles

HyMeX: A 10-Year Multidisciplinary Program on the Mediterranean Water Cycle

Drobinski, P. ... et. al.-- 20 pages, 10 figures, 1 table, supplement material http://journals.ametsoc.org/doi/suppl/10.1175/BAMS-D-12-00244.1HyMeX strives to improve our understanding of the Mediterranean water cycle, its variability from the weather-scale events to the seasonal and interannual scales, and its characteristics over one decade (2010–20), with a special focus on hydrometeorological extremes and the associated social and economic vulnerability of the Mediterranean territoriesHyMeX was developed by an international group of scientists and is currently funded by a large number of agencies. It has been the beneficiary of financial contributions from CNRS; Météo-France; CNES; IRSTEA; INRA; ANR; Collectivité Territoriale de Corse; KIT; CNR; Université de Toulouse; Grenoble Universités; EUMETSAT; EUMETNET; AEMet; Université Blaise Pascal, Clermont Ferrand; Université de la Méditerranée (Aix-Marseille II); Université Montpellier 2; CETEMPS; Italian Civil Protection Department; Université Paris- Sud 11; IGN; EPFL; NASA; New Mexico Tech; IFSTTAR; Mercator Ocean; NOAA; ENEA; TU Delft; CEA; ONERA; IMEDEA; SOCIB; ETH; MeteoCat; Consorzio LAMMA; IRD; National Observatory of Athens; Ministerio de Ciencia e Innovación; CIMA; BRGM; Wageningen University and Research Center; Department of Geophysics, University of Zagreb; Institute of Oceanography and Fisheries, Split, Croatia; INGV; OGS; Maroc Météo; DHMZ; ARPA Piemonte; ARPA-SIMC Emilia-Romagna; ARPA Calabria; ARPA Friuli Venezia Giulia; ARPA Liguria; ISPRA; University of Connecticut; Università degli Studi dell'Aquila; Università di Bologna; Università degli Studi di Torino; Università degli Studi della Basilicata; Università La Sapienza di Roma; Università degli Studi di Padova; Università del Salento; Universitat de Barcelona; Universitat de les Illes Balears; Universidad de Castilla-La Mancha; Universidad Complutense de Madrid; MeteoSwiss; and DLR. It also received support from the European Community's Seventh Framework Programme (e.g., PERSEUS, CLIM-RUN)Peer reviewe

Aeolus Calibration, Validation and Science Campaigns

Since 2007, a series of ESA supported airborne campaigns have been essential to the development of the Aeolus Doppler Wind Lidar satellite mission, which was successfully launched on 22 September 2018 and is providing a novel wind and aerosol profile data. A core element of the Aeolus Cal/Val activities is DLRs A2D wind lidar on-board the DLR Falcon aircraft, an airborne demonstrator for the Aeolus ALADIN satellite instrument flown in combination with the 2-µm Doppler Wind Lidar reference system. Following the pre-launch WindVal-I and –II campaigns in 2015 and 2016, a number of calibration and validation campaigns have been successfully implemented: WindVal-III providing early Cal/Val results in November 2018 only three months after the Aeolus launch, AVATAR-E in May 2019 focussing on the Cal/Val over Central Europe, and AVATAR-I in September 2019 providing Cal/Val information in the North Atlantic and Arctic flying from Iceland

Use of CCD to Detect Terrestrial Cosmic Rays at Ground Level: Altitude Vs. Underground Experiments, Modeling and Numerical Monte Carlo Simulation

International audienceMulti-site characterization of terrestrial radiation using a CCD camera and numerical simulations demonstrate the CCD sensitivity to low energy protons and muons and the role of alpha-emitters in its response at sea level

Aeolus calibration, validation and science campaigns

Since 2007, a series of ESA supported airborne campaigns have been essential to the development of the Aeolus Doppler Wind Lidar satellite mission, which was successfully launched on 22 September 2018 and is providing a novel wind and aerosol profile data. A core element of the Aeolus Cal/Val activities is DLR’s A2D wind lidar on-board the DLR Falcon aircraft, an airborne demonstrator for the Aeolus ALADIN satellite instrument flown in combination with the 2-µm Doppler Wind Lidar reference system. Following the pre-launch WindVal-I and –II campaigns in 2015 and 2016, a number of calibration and validation campaigns have been successfully implemented: WindVal-III providing early Cal/Val results in November 2018 only three months after the Aeolus launch, AVATAR-E in May 2019 focussing on the Cal/Val over Central Europe, and AVATAR-I in September 2019 providing Cal/Val information in the North Atlantic and Arctic flying from Iceland. The airborne validation is also being supported through balloon flights in the tropical UTLS and lower stratosphere in the frame of the CNES Stratéole-2 stratospheric balloon activities. In the frame of the ESA supported pre-Stratéole-2 campaign, eight stratospheric balloons have been launched from the Seychelles in November/December 2019 providing unique upper level wind data for the Aeolus validation. The largest impact of the Aeolus observations is expected in the Tropics, and in particular over the Tropical oceans, where only a limited number of wind profile information is provided by ground based observations. Aeolus provides key direct measurements which are of importance to correctly constrain the wind fields in models. In addition, Aeolus observations have the potential to further enhance our current knowledge on aerosols and clouds by globally providing optical properties products that include atmospheric backscatter and extinction coefficient profiles, lidar ratio profiles and scene classification. In the tropics, a particularly interesting case is the outflow of Saharan dust and its impact on micro-physics in tropical cloud systems. The region off the coast of West Africa allows the study of the Saharan Aerosol layer, African Easterly Waves and Jets, Tropical Easterly Jet, as well as the deep convection in ITCZ. Together with international partners, ESA is currently implementing a Tropical campaign in July 2020 with its base in Cape Verde that comprises both airborne and ground-based activities addressing the tropical winds and aerosol validation, as well as science objectives. The airborne component includes the DLR Falcon-20 carrying the A2D and 2-µm Doppler Wind lidars, the NASA P-3 Orion with the DAWN and HALO lidar systems, the APR Ku-, Ka- and W-band Doppler radar and drop sondes, and a Slovenian small aircraft providing in-situ information from aethalometers, nephelometers and optical particle counters. The ground-based component led by the National Observatory of Athens is a collaboration of European teams providing aerosol and cloud measurements with a range of lidar, radar and radiometer systems, as well as a drone providing in-situ aerosol observations. In addition, the participation airborne capabilities by NOAA and LATMOS/Meteo France are currently being investigated. This paper will provide a summary of the Aeolus campaign focussing on the planned tropical campaign