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An autonomous above-water system for the validation of ocean color radiance data / G. Ziborni in IEEE Transactions on geoscience and remote sensing, vol 42 n° 2 (February 2004)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 42 n° 2 (February 2004) . - pp 401 - 415 Titre : An autonomous above-water system for the validation of ocean color radiance data Type de document : Article/Communication Auteurs : G. Ziborni, Auteur ; F. Melin, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 401 - 415 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] Adriatique, mer [Termes IGN] analyse comparative [Termes IGN] eaux côtières [Termes IGN] étalonnage radiométrique [Termes IGN] exitance spectrale [Termes IGN] image Aqua-MODIS [Termes IGN] image Envisat-MERIS [Termes IGN] image Seawifs [Termes IGN] luminance lumineuse [Termes IGN] photométrie [Termes IGN] radiance Résumé : (Auteur) An operational system for autonomous above-water radiance measurements, called the SeaWiFS Photometer Revision for Incident Surface Measurements (SeaPRISM), was deployed at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea and used for the validation of remote sensing radiometric products in coastal waters. The SeaPRISM data were compared with simultaneous data collected from an independent in-water system for a wide variety of sun elevations along with different atmospheric, seawater, and sea state conditions. The average absolute differences between the above- and in-water determinations of water-leaving radiances (computed linearly) were less than 4.5% in the 412-555-nm spectral interval. A similar comparison for normalized water-leaving radiances showed average absolute differences less than 5.1%. The comparison between normalized water-leaving radiances computed from remote sensing and SeaPRISM matchup data, showed absolute spectral average (linear) differences of 17.0%, 22.1%, and 20.8% for SeaWiFS, MODIS, and MERIS, respectively. The results, in keeping with those produced by independent in-water systems, suggest the feasibility of operational coastal networks of autonomous above-water radiometers deployed on fixed platforms (towers, lighthouses, navigation aids, etc.) to support ocean color validation activities. Numéro de notice : A2004-137 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2003.821064 En ligne : https://doi.org/10.1109/TGRS.2003.821064 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26664 [article]

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Phenomenological analysis of simulated signals observed over shaded areas in an urban scene / Christophe Miesch in IEEE Transactions on geoscience and remote sensing, vol 42 n° 2 (February 2004)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 42 n° 2 (February 2004) . - pp 434 - 442 Titre : Phenomenological analysis of simulated signals observed over shaded areas in an urban scene Type de document : Article/Communication Auteurs : Christophe Miesch, Auteur ; Xavier Briottet , Auteur ; Yann H. Kerr, Auteur Année de publication : 2004 Article en page(s) : pp 434 - 442 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] bande spectrale [Termes IGN] diffusion du rayonnement [Termes IGN] image à haute résolution [Termes IGN] image panchromatique [Termes IGN] milieu urbain [Termes IGN] ombre [Termes IGN] réfraction atmosphérique [Termes IGN] scène [Termes IGN] simulation [Termes IGN] transfert radiatif Résumé : (Auteur) This paper analyzes the signal measured by optical remote sensors when acquiring data over a shaded part of an urban scene. The signal is much lower for this kind of target than for others because there is no direct downward irradiance. Here, a simple urban scene is considered with a shaded area. The signal observed by a high spatial resolution satellite sensor over an ordinary panchromatic band (500-700 nm) is computed thanks to a radiative transfer code [advanced modeling of the atmospheric radiative transfer for inhomogeneous surfaces (Amartis)] capable of dealing with ground topography and heterogeneity. The signal is analyzed, and it appears that environmental effects play a significant role. Moreover, because of the scattering that occurs at shorter wavelengths, it is also shown that a widening of the band to 440 nm sharpens the difference between signals coming from two different ground types (for whose the difference of reflectance is constant and equal to 0.1) by about 10%. This demonstrates that the band widening may be beneficial to observation in shadow, mainly because of scattering effects. A more realistic scene is also considered, in which each part is associated with realistic spectral properties. This simply shows the importance of the thematic in the choice of band, as it determines the effect of the widening. Numéro de notice : A2004-138 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2003.814916 En ligne : https://doi.org/10.1109/TGRS.2003.814916 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26665 [article]

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Reconstruction of backscatter and extinction coefficients in Lidar: a stochastic filtering approach / José M. Bioucas-Dias in IEEE Transactions on geoscience and remote sensing, vol 42 n° 2 (February 2004)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 42 n° 2 (February 2004) . - pp 443 - 456 Titre : Reconstruction of backscatter and extinction coefficients in Lidar: a stochastic filtering approach Type de document : Article/Communication Auteurs : José M. Bioucas-Dias, Auteur ; J.M.N. Leitao, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 443 - 456 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] champ aléatoire de Markov [Termes IGN] coefficient de rétrodiffusion [Termes IGN] données lidar [Termes IGN] filtrage statistique [Termes IGN] filtre de Kalman [Termes IGN] processus stochastique Résumé : (Auteur) Reconstruction of the backscatter and extinction coefficients is a crucial step in many quantitative remote sensing applications, such as radar, light detection and ranging (lidar), and sonar. We present a novel stochastic filtering approach for the estimation of the backscatter and extinction coefficients from time-range elastic-backscatter lidar data. The Bayesian perspective is adopted; we take as prior a causal first-order autoregressive Gauss-Markov random field tailored to enforce smoothness on time and range dimensions. By using a reduced-order state-space representation of the prior, we derive a suboptimal stochastic filter that recursively computes the backscatter and extinction coefficients at each range-time inversion cell. The estimator is a kind of adaptive extended Kalman filter, being efficient from the computational point of view. A set of experiments illustrates the effectiveness of the proposed approach, namely its advantage over the classical Klett deterministic approach. Numéro de notice : A2004-139 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2003.817216 En ligne : https://doi.org/10.1109/TGRS.2003.817216 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26666 [article]

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