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Termes IGN > sciences naturelles > physique > optique > optique physique > radiométrie > rayonnement électromagnétique > spectre électromagnétique > bande spectrale
bande spectraleSynonyme(s)canal spectral |
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Continental scale hotspot observations of Australia at sub-degree angular resolution from POLDER / F. Grant in International Journal of Remote Sensing IJRS, vol 25 n° 18 (September 2004)
[article]
Titre : Continental scale hotspot observations of Australia at sub-degree angular resolution from POLDER Type de document : Article/Communication Auteurs : F. Grant, Auteur ; C. Heyraud, Auteur ; François-Marie Bréon, Auteur Année de publication : 2004 Article en page(s) : pp 3625 - 3636 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse comparative
[Termes IGN] Australie
[Termes IGN] bande spectrale
[Termes IGN] carte de la végétation
[Termes IGN] image ADEOS-POLDER
[Termes IGN] réflectance végétale
[Termes IGN] tâche claireRésumé : (Auteur) Angular signatures of the innermost few degrees of the hotspot are retrieved on Australian land surfaces with an angular resolution better than 0.5° and a spatial resolution of around 150 km, using data from the Polarization and Directionality of the Earth's Reflectances (POLDER) instrument on the Advanced Earth Observing Satellite (ADEOS). These constitute the first comprehensive hotspot measurements at the scale of a continent. The retrieval technique requires that the hotspot characteristics at small angular scales are approximately invariant over a region of about 50km in extent, but accommodates pixel-to-pixel variations in the other characteristics, of the angular signature. Continental maps of the amplitude and half-width of the hotspot, in two spectral bands, are presented for two 41-day orbit cycles in different seasons and compared with a vegetation map. The half-widths are predominantly in the range 0.5°-1.5°, with no systematic difference between the 670 nm and 865 nm bands, and show little spatial structure. The maps of hotspot amplitude display significant spatial structure that corresponds closely to the vegetation map. Generally, areas of trees and tall shrubs are characterized by low hotspot amplitudes, while cropland, grassland and areas of low shrubs have high hotspot amplitudes. The evergreen broadleaf eucalypt forests are notable in that the amplitude is low at 670 nm and high at 865 nm. Numéro de notice : A2004-354 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160310001648000 En ligne : https://doi.org/10.1080/01431160310001648000 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26881
in International Journal of Remote Sensing IJRS > vol 25 n° 18 (September 2004) . - pp 3625 - 3636[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04161 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Extrapolation of the aerosol reflectance from the near-infrared to the visible : the single-scattering epsilon vs multiple-scattering epsilon method / M. Wang in International Journal of Remote Sensing IJRS, vol 25 n° 18 (September 2004)
[article]
Titre : Extrapolation of the aerosol reflectance from the near-infrared to the visible : the single-scattering epsilon vs multiple-scattering epsilon method Type de document : Article/Communication Auteurs : M. Wang, Auteur Année de publication : 2004 Article en page(s) : pp 3637 - 3650 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] aérosol
[Termes IGN] atmosphère terrestre
[Termes IGN] bande visible
[Termes IGN] correction atmosphérique
[Termes IGN] correction d'image
[Termes IGN] diffusion du rayonnement
[Termes IGN] exitance spectrale
[Termes IGN] image Seawifs
[Termes IGN] radiance
[Termes IGN] rayonnement proche infrarougeRésumé : (Auteur) In the atmospheric correction algorithm for Sea-viewing Wide Fieldof-view Sensor, the effects of the spectral variation of the aerosol radiance contributions at the two near-infrared (NIR) bands are estimated directly from sensor-measured radiance. The aerosol effects at the NIR are then extrapolated into, the visible through a process of aerosol model selection from evaluation of the NIR single-scattering epsilon value, which is defined as the ratio of the single-scattering aerosol reflectance between two NIR bands. The aerosol radiance contribution at the visible wavelengths is then removed. In this paper, a slightly different approach in the aerosol model selection and extrapolation, i.e. using the NIR multiple-scattering epsilon instead of the single-scattering epsilon, is examined. The NIR multiple-scattering epsilon is the ratio of the aerosol multiple-scattering reflectance between two NIR wavelengths. Simulations show that, in general, both methods give comparable results. Statistically, more than 95% of cases in the retrieved ocean colour spectrum are within required accuracy for both methods. For clear atmosphere, however, the results of the atmospheric correction using the single-scattering epsilon method usually performed slightly better than the multiple-scattering epsilon method. On the other hand, for the large aerosol optical thickness the multiple-scattering epsilon method has slightly better retrievals for the Tropospheric aerosols. Some detailed analyses and discussions are provided to explain differences in these two approaches for extrapolating and retrieving the aerosol effects in the visible. Numéro de notice : A2004-355 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160310001619599 En ligne : https://doi.org/10.1080/01431160310001619599 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26882
in International Journal of Remote Sensing IJRS > vol 25 n° 18 (September 2004) . - pp 3637 - 3650[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04161 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Evaluating airborne hyperspectral imagery for rangeland assessment in south Texas / James H. Everitt in Geocarto international, vol 19 n° 3 (September - November 2004)
[article]
Titre : Evaluating airborne hyperspectral imagery for rangeland assessment in south Texas Type de document : Article/Communication Auteurs : James H. Everitt, Auteur ; C. Yang, Auteur ; M.R. Davis, Auteur Année de publication : 2004 Article en page(s) : pp 23 - 31 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande visible
[Termes IGN] composition colorée
[Termes IGN] ERDAS Imagine
[Termes IGN] flore locale
[Termes IGN] image hyperspectrale
[Termes IGN] occupation du sol
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] réflectance spectrale
[Termes IGN] Texas (Etats-Unis)Résumé : (Auteur) Airborne hyperspectral imagery was evaluated for differentiating among rangeland ecological variables on two range sites (tight sandy loam and shallow ridge) on south Texas rangelands. Field spectroradiometric reflectance measurements made on dominant vegetation (plant species and vegetation mixtures) and soil land-use types on the two sites identified six wavelengths [five visible and one near-infrared (NIR)] where significant spectral differences occurred among the parameters. The spectral bands that corresponded to these wavelengths were extracted from the 128-band hyperspectral images obtained of each site and used to develop false color composites that were subjected to computer classifications and accuracy assessments. The bands selected for the composites included the green (498.9 nm), yellow-green (549.7 nm), orange (629.6 nm), red (651.3 nm), dark red (680.4 nm), and NIR (825.5 tim). Accuracy assessments performed on the classification maps of four false color composites of the tight sandy loam site had overall accuracies ranging from 76% to 85%; the highest accuracy was obtained from the composite made up of the NIR, red, and yellow-green bands. Accuracy assessments performed on the classification maps of three composites of the shallow ridge site had overall accuracies ranging from 74% to 77%; the highest accuracy was acquired from a composite comprised of the NIR, orange, and yellow-green bands. Overall accuracies were considered good and indicate that several band combinations can be used successfully to differentiate among, rangeland parameters in southern Texas. Key Words: remote sensing, hyperspectral imagery, reflectance, false color composite imagery, accuracy assessment. Numéro de notice : A2004-478 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040408542314 Date de publication en ligne : 02/01/2008 En ligne : https://doi.org/10.1080/10106040408542314 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26996
in Geocarto international > vol 19 n° 3 (September - November 2004) . - pp 23 - 31[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-04031 RAB Revue Centre de documentation En réserve L003 Disponible Monitoring surface soil moisture in post-harvest rice areas using C-band radar imagery in NorthEast Thailand / S. Kaojarern in Geocarto international, vol 19 n° 3 (September - November 2004)
[article]
Titre : Monitoring surface soil moisture in post-harvest rice areas using C-band radar imagery in NorthEast Thailand Type de document : Article/Communication Auteurs : S. Kaojarern, Auteur ; Thuy Le Toan, Auteur ; M.W. Davidson, Auteur Année de publication : 2004 Article en page(s) : pp 61 - 71 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] agriculture
[Termes IGN] bande C
[Termes IGN] humidité du sol
[Termes IGN] image ERS-SAR
[Termes IGN] image radar
[Termes IGN] image Radarsat
[Termes IGN] rizière
[Termes IGN] seuillage d'image
[Termes IGN] surveillance agricole
[Termes IGN] surveillance météorologique
[Termes IGN] ThaïlandeRésumé : (Auteur) The objective of this study is to estimate the residual surface soil moisture of rice fields after harvesting, in Northeast Thailand, using Cband SAR images. Such information is use 1 to determine possibilities of cultivating additional shortcycle crops after the harvesting of the main rice crop. To accomplish this objective this study exploits three Cband SAR images acquired over the test area along with simultaneous ground measurements collected in support of analysis of the SAR images. The main parameters measured on the ground were: the volumetric moisture content of the soil using time domain reflectrometry (TDR), the surface roughness, using profile data, and residue cover. Other field environmental factors that might affect radar backscattering, including the topography of rice terraces (elevation, slope, and aspect), bund height between rice fields, soil types, and density of sparse tree stands were also acquired and registered to the image data. Before the analysis, the SAR images were calibrated, registered, and then filtered using multitemporal and spatial filters to reduce variability of the radar backscattering coefficient due to speckle. The measured soil moisture values were then correlated with the radar backscattering coefficients of the experimental plots and the results interpreted in terms of the main environmental factors. Varying residue cover and field aspect angles were found to significantly affect the relationship between radar backscatter and soil moisture content and therefore had to be taken into account before inverting the image data into soil moisture maps. Overall it was found that two soil moisture classes could reliably be separated using the SAR images, and that soil moisture maps could be obtained through a simple inversion technique based on applying a threshold to the SAR images. Analyses of these resulting moisture maps indicate that SAR data is useful to monitor and map surface soil moisture in rice fields after harvest. Numéro de notice : A2004-479 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040408542319 Date de publication en ligne : 02/01/2008 En ligne : https://doi.org/10.1080/10106040408542319 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26997
in Geocarto international > vol 19 n° 3 (September - November 2004) . - pp 61 - 71[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-04031 RAB Revue Centre de documentation En réserve L003 Disponible Use of hyperspectral derivative ratios in the red-edge region to identify plant stress responses to gas leaks / K.L. Smith in Remote sensing of environment, vol 92 n° 2 (15/08/2004)
[article]
Titre : Use of hyperspectral derivative ratios in the red-edge region to identify plant stress responses to gas leaks Type de document : Article/Communication Auteurs : K.L. Smith, Auteur ; M.D. Steven, Auteur ; J.J. Colls, Auteur Année de publication : 2004 Article en page(s) : pp 207 - 217 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande visible
[Termes IGN] blé (céréale)
[Termes IGN] canalisation
[Termes IGN] feuille (végétation)
[Termes IGN] gaz
[Termes IGN] herbe
[Termes IGN] image hyperspectrale
[Termes IGN] oxygène (O²)
[Termes IGN] pollution
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] réflectance végétale
[Termes IGN] végétationRésumé : (Auteur) Hyperspectral features in the red-edge region were tested as an index of plant stress responses to soil -oxygen depletion. The aim was to provide the basis for a warning system to identify natural gas leakage by the spectral responses of plants growing in the affected soil.
Elevated concentrations of natural gas in the soil atmosphere were used to deplete oxygen concentrations around the roots of grass, wheat (Hordeum vulgare cv Claire) and bean (Vicia faba cv Clipper) growing in a field facility. Visible symptoms due to the natural gas included reduced growth of the plants and chlorosis of the leaves.
Spectral responses included increased reflectance in the visible wavelengths and decreased reflectance in the near infra-red. Derivative analysis identified features within the red-edge at 720-730 and 702 nm. Ratios of the magnitude of the derivative at 725 to that at 702 nm were less in areas where gas was present. This ratio enabled identification of stress due to gas leakage up to 7 days before visible symptoms were observed and also at the edges of gassed plots where visible symptoms were not expressed. The technique was able to identify stress responses to long-term leaks in all the crops tested but to short-term leaks only in grass. This study therefore suggests that under appropriate conditions remote sensing could be used to detect pipeline gas leaks from decreases in the ratio of peaks within the red-edge.Numéro de notice : A2004-334 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.06.002 En ligne : https://doi.org/10.1016/j.rse.2004.06.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26861
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