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Spatial resolution and processing tradeoffs for HYDROS: application of reconstruction and resolution enhancement techniques / David G. Long in IEEE Transactions on geoscience and remote sensing, vol 43 n° 1 (January 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 1 (January 2005) . - pp 3 - 12 Titre : Spatial resolution and processing tradeoffs for HYDROS: application of reconstruction and resolution enhancement techniques Type de document : Article/Communication Auteurs : David G. Long, Auteur Année de publication : 2005 Article en page(s) : pp 3 - 12 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] accentuation d'image [Termes IGN] bande L [Termes IGN] capteur (télédétection) [Termes IGN] humidité du sol [Termes IGN] HYDROS [Termes IGN] Hydrospheric State [Termes IGN] image à basse résolution [Termes IGN] mission spatiale [Termes IGN] radiomètre à hyperfréquence [Termes IGN] reconstruction d'image Résumé : (Auteur) Recent developments in reconstruction and resolution enhancement for microwave instruments suggest a possible tradeoff between computation, resolution, and downlink data rate based on postcollection reconstruction/resolution enhancement processing. The Hydrospheric State mission is designed to measure global soil moisture and freeze/thaw state in support of weather and climate prediction, water, energy, and carbon cycle studies, and natural hazards monitoring. It will use an active and passive L-band microwave system that optimizes measurement accuracy, spatial resolution, and coverage. The active channels use synthetic aperture radar-type processing to achieve fine spatial resolution, requiring a relatively high downlink data rate and ground processor complexity. To support real-time applications and processing, an optional postcollection reconstruction and resolution enhancement method is investigated. With this option, much lower rate real-aperture radar data are used along with ground-based postprocessing algorithms to enhance the resolution of the observations to achieve the desired 10-km resolution. Several approaches are investigated in this paper. It is determined that a reconstruction/resolution enhancement technique combining both forward- and aft-looking measurements enables estimation of 10-km resolution or better backscatter values at acceptable accuracy. Key tradeoffs to achieve this goal are considered. Numéro de notice : A2005-057 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.838385 En ligne : https://doi.org/10.1109/TGRS.2004.838385 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27195 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Detection of stationary foliage-obscured targets by polarimetric millimeter-wave radar / A.Y. Nashashibi in IEEE Transactions on geoscience and remote sensing, vol 43 n° 1 (January 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 1 (January 2005) . - pp 13 - 23 Titre : Detection of stationary foliage-obscured targets by polarimetric millimeter-wave radar Type de document : Article/Communication Auteurs : A.Y. Nashashibi, Auteur ; F.T. Ulaby, Auteur Année de publication : 2005 Article en page(s) : pp 13 - 23 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] angle d'incidence [Termes IGN] cible cachée [Termes IGN] décorrélation [Termes IGN] détection de cible [Termes IGN] distorsion d'image [Termes IGN] feuille (végétation) [Termes IGN] polarimétrie radar [Termes IGN] rétrodiffusion Résumé : (Auteur) This paper introduces a technique to detect the presence of foliage-obscured targets using millimeter-wave radars operating at near-grazing incidence. Radar return from a scene where a target is concealed behind foliage consists of both foliage backscatter return and a polarimetrically distorted and reduced target return. A data acquisition and signal processing technique that takes advantage of temporal decorrelations in foliage is proposed to enhance target detection and resolve it from foliage. Futhermore, an inversion technique is proposed to remove the polarimetric distortions in the target response. The techniques are verified through a series of indoor and outdoor experiments. Numéro de notice : A2005-058 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.838378 En ligne : https://doi.org/10.1109/TGRS.2004.838378 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27196 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Estimation of gravity wave momentum flux with spectroscopic imaging / J. Tang in IEEE Transactions on geoscience and remote sensing, vol 43 n° 1 (January 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 1 (January 2005) . - pp 103 - 109 Titre : Estimation of gravity wave momentum flux with spectroscopic imaging Type de document : Article/Communication Auteurs : J. Tang, Auteur ; F. Kamalabadi, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 103 - 109 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] analyse spectrale [Termes IGN] effet atmosphérique [Termes IGN] extraction [Termes IGN] perturbation [Termes IGN] rayonnement électromagnétique [Termes IGN] spectroscopie Résumé : (Auteur) Atmospheric gravity waves play a significant role in the dynamics and thermal balance of the upper atmosphere. In this paper, we present a novel technique for automated and robust calculation of momentum flux of high-frequency quasi-monochromatic wave components from spectroscopic imaging and horizontal radar wind measurements. Our approach uses the two-dimensional (2-D) cross periodogram of two consecutive Doppler-shifted time-differenced (TD) images to identify wave components and estimate intrinsic wave parameters. Besides estimating the average perturbation of dominant waves in the whole field of view, this technique applies 2D short-space Fourier transform to the TD images to identify localized wave events. With the wave parameters acquired, the momentum flux carried by all vertically propagating wave components is calculated using an analytical model relating the measured intensity perturbation to the wave amplitude. This model is tested by comparing wave perturbation amplitudes inferred from spectroscopic images with those from sodium lidar temperature measurements. The proposed technique enables characterization of the variations in the direction and strength of gravity waves with high temporal resolution for each clear data-taking night. The nightly results provide statistical information for investigating seasonal and geographical variations in momentum flux of gravity waves. Numéro de notice : A2005-059 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.836268 En ligne : https://doi.org/10.1109/TGRS.2004.836268 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27197 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Robust multiple estimator systems for the analysis of biophysical parameters from remotely sensed data / Lorenzo Bruzzone in IEEE Transactions on geoscience and remote sensing, vol 43 n° 1 (January 2005)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 43 n° 1 (January 2005) . - pp 159 - 174 Titre : Robust multiple estimator systems for the analysis of biophysical parameters from remotely sensed data Type de document : Article/Communication Auteurs : Lorenzo Bruzzone, Auteur ; F. Melgani, Auteur Année de publication : 2005 Article en page(s) : pp 159 - 174 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] estimateur [Termes IGN] Perceptron multicouche [Termes IGN] régression [Termes IGN] réseau neuronal artificiel [Termes IGN] télédétection spatiale [Termes IGN] variable biophysique (végétation) Résumé : (Auteur) In this paper, an approach based on multiple estimator systems (MESs) for the estimation of biophysical parameters from remotely sensed data is proposed. The rationale behind the proposed approach is to exploit the peculiarities of an ensemble of different estimators in order to improve the robustness (and in some cases the accuracy) of the estimation process. The proposed MESs can be implemented in two conceptually different ways. One extends the use of an approach previously proposed in the regression literature to the estimation of biophysical parameters from remote sensing data. This approach integrates the estimates obtained from the different regression algorithms making up the ensemble by a direct linear combination (combination-based approach). The other consists of a novel approach that provides as output the estimate obtained by the regression algorithm (included in the ensemble) characterized by the highest expected accuracy in the region of the feature space associated with the considered pattern (selection-based approach). This estimator is identified based on a proper partition of the feature space. The effectiveness of the proposed approach has been assessed on the problem of estimating water quality parameters from multispectral remote sensing data. In particular, the presented MES-based approach has been evaluated by considering different operational conditions where the single estimators included in the ensemble are: 1) based on the same or on different regression methods; 2) characterized by different tradeoffs between correlated errors and accuracy of the estimates; 3) trained on samples affected or not by measurement errors. In the definition of the ensemble particular attention is devoted to support vector machines (SVMs), which are a promising approach to the solution of regression problems. In particular, a detailed experimental analysis on the effectiveness of SVMs for solving the considered estimation problem is presented. The experimental results point out that the SVM method is effective and that the proposed MES approach is capable of increasing both the robustness and accuracy of the estimation process. Numéro de notice : A2005-060 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.839818 En ligne : https://doi.org/10.1109/TGRS.2004.839818 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27198 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-05011	RAB	Revue	Centre de documentation	En réserve L003	Disponible