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Evaluation of speckle noise MAP filtering algorithms applied to SAR images / F.N.S. Medeiros in International Journal of Remote Sensing IJRS, vol 24 n° 24 (December 2003)
[article]
Titre : Evaluation of speckle noise MAP filtering algorithms applied to SAR images Type de document : Article/Communication Auteurs : F.N.S. Medeiros, Auteur ; N.D.A. Mascarenhas, Auteur ; L.F. Costa, Auteur Année de publication : 2003 Article en page(s) : pp 5197 - 5218 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse de groupement
[Termes IGN] chatoiement
[Termes IGN] filtrage du rayonnement
[Termes IGN] filtre de déchatoiement
[Termes IGN] limite de résolution radiométrique
[Termes IGN] radar à antenne synthétique
[Termes IGN] transformation de HoughRésumé : (Auteur) This work proposes new speckle reduction filters for multilook, amplitude detected Synthetic Aperture Radar (SAR) images based on the maximum a posteriori (MAP) approach and compares their performance. The new filters use an adaptive approach based on the one-dimensional k-means clustering algorithm over the variance ratio and also a regiongrowing procedure. The trade-off between the loss of radiometric resolution and edge preservation is evaluated in the filtered images. In order to obtain quantitative measures of the speckle reduction and of the edge blurring, we used some parameters such as the classical equivalent number of looks and the Hough transform. Experiments have been carried out with natural images corrupted with synthetic speckle noise following the Rayleigh and square root of gamma distributions and with real SAR images. Numéro de notice : A2003-341 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115148 En ligne : https://doi.org/10.1080/0143116031000115148 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22636
in International Journal of Remote Sensing IJRS > vol 24 n° 24 (December 2003) . - pp 5197 - 5218[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03241 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Global structure of marine wind speed variability derived from Topex altimeter data / G. Chen in International Journal of Remote Sensing IJRS, vol 24 n° 24 (December 2003)
[article]
Titre : Global structure of marine wind speed variability derived from Topex altimeter data Type de document : Article/Communication Auteurs : G. Chen, Auteur ; S.W. Bi, Auteur ; J. Ma, Auteur Année de publication : 2003 Article en page(s) : pp 5119 - 5133 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] climat terrestre
[Termes IGN] courant aérien
[Termes IGN] données altimétriques
[Termes IGN] données Topex-Poseidon
[Termes IGN] géophysique externe
[Termes IGN] océanographie spatiale
[Termes IGN] Pacifique (océan)
[Termes IGN] surface de la mer
[Termes IGN] vague
[Termes IGN] ventRésumé : (Auteur) As the largest source of momentum for the ocean surface, wind affects the full range, of oceanic motion-from individual surface waves to complete current systems. The marine surface wind is among the critical geophysical parameters which determine the most fundamental aspects of the ocean. Using six years (1993-1998) of TOPEX altimeter data with an unprecedented accuracy and continuity, a detailed investigation of the global structure of marine wind climatology and variability is carried out. It is found that the overall pattern of wind climatology is basically determined by solar radiation and therefore dominated by zonal features, while that of the wind variability is largely 'event' determined and thereby dominated by regional features. Consequently, wind climatology and wind variability show a complex relationship in their magnitude of intensity. Strong winds may be associated with high variabilities, such as in the westerlies of the North Atlantic and North Pacific; they may also be associated with low variabilities, such as in the westerlies of the Southern Ocean. Meanwhile, weak wind zones like the doldrums in the western equatorial Pacific can have a very low level of annual variability, while a very high level of interannual variability. The Asian monsoon system has a lower than average climatological mean speed, but exhibits extremely high annual variability. The phase distributions of wind variations carry combined information of climatology and variability. Effects of the Asian monsoon and marine storms are manifested on top of the basically zonal phase pattern. Statistics suggest that semiannual variability exceeds annual variability for 12.2% of the world's oceans, and interannual variability exceeds annual variability for 26.4% of the world's oceans. Numéro de notice : A2003-340 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000082091 En ligne : https://doi.org/10.1080/0143116031000082091 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22635
in International Journal of Remote Sensing IJRS > vol 24 n° 24 (December 2003) . - pp 5119 - 5133[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03241 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Geographical weighting as a further refinement to regression modelling: an example focused on the NDVI-rainfall relationship / Giles M. Foody in Remote sensing of environment, vol 88 n° 3 (15/12/2003)
[article]
Titre : Geographical weighting as a further refinement to regression modelling: an example focused on the NDVI-rainfall relationship Type de document : Article/Communication Auteurs : Giles M. Foody, Auteur Année de publication : 2003 Article en page(s) : pp 283 - 293 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle de régression
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] précipitationRésumé : (Auteur) The regression analyses undertaken commonly in remote sensing are aspatial, ignoring the locational information associated with each sample site at which the variables under study were measured. Typically, basic ordinary least squares regression analysis is used to derive a relationship that is believed to be uniformly applicable across the study area. Although such global analyses may appear satisfactory, often with large coefficients of determination derived, they may provide an inappropriate description of the relationship between the variables under study. In particular, a global regression analysis may miss local detail that can be significant if the relationship is spatially nonstationary. Local statistical approaches, such as geographically weighted regression, include the spatial coordinates of the sample sites in the analysis and may provide a more appropriate basis for the investigation of the relationship between variables. The potential value of geographically weighted regression to the remote sensing community is illustrated with reference to the relationship between the normalised difference vegetation index (NDVI) and rainfall over north Africa and the Middle East over an 8-year period. For each year, spatial non-stationarity was evident, particularly with regard to the slope parameter of the regression model. Moreover, the conventional ordinary least squares regression models, while superficially strong (minimum R2 == 0.67), were relatively poor local descriptors of the relationship. Relative to this, the geographically weighted approach to regression provided considerably stronger relationships from the same data sets (minimum R2 = 0.96) as well as highlighting areas of local variation. The implications of the difference in the outputs from the two types of regression analysis are illustrated with reference to the use of the derived NDVI-rainfall relationships in mapping desert extent. For example, with the data relating to 1987 the southern limit of the Sahara was generally estimated to lie at a more southerly position when the relationship derived from OLS rather than geographically weighted regression was used. Numéro de notice : A2003-346 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.08.004 En ligne : https://doi.org/10.1016/j.rse.2003.08.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26426
in Remote sensing of environment > vol 88 n° 3 (15/12/2003) . - pp 283 - 293[article]Snow-cover mapping in forest by constrained linear spectral unimixing of MODIS data / D. Vikhamar in Remote sensing of environment, vol 88 n° 3 (15/12/2003)
[article]
Titre : Snow-cover mapping in forest by constrained linear spectral unimixing of MODIS data Type de document : Article/Communication Auteurs : D. Vikhamar, Auteur ; R. Solberg, Auteur Année de publication : 2003 Article en page(s) : pp 309 - 323 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse des mélanges spectraux
[Termes IGN] cartographie thématique
[Termes IGN] classification
[Termes IGN] forêt
[Termes IGN] image Terra-MODIS
[Termes IGN] neigeRésumé : (Auteur) A snow-cover mapping method accounting for forests (SnowFrac) is presented. SnowFrac uses spectral unmixing and endmember constraints to estimate the snow-cover fraction of a pixel. The unmixing is based on a linear spectral mixture model, which includes endmembers for snow, conifer, branches of leafless deciduous trees and snow-free ground. Model input consists of a land-cover fraction map and endmember spectra. The landcover fraction map is applied in the unmixing procedure to identify the number and types of endmembers for every pixel, but also to set constraints on the area fractions of the forest endmembers. SnowFrac was applied on two Terra Moderate Resolution Imaging Spectroradiometer (MODIS) images with different snow conditions covering a forested area in southern Norway. Six experiments were carried out, each with different endmember constraints. Estimated snow-cover fractions were compared with snow-cover fraction reference maps derived from two Landsat Enhanced Thematic Mapper Plus (ETM+) images acquired the same days as the MODIS images. Results are presented for non-forested areas, deciduous forests, coniferous forests and mixed deciduous/coniferous forests. The snow-cover fraction estimates are enhanced by increasing constraints introduced to the unmixing procedure. The classification accuracy shows that 96% of the pixels are classified with less than 20% error (absolute units) on 7 May 2001 when all forested and non-forested areas are included. The corresponding figure for 4 May 2000 is 88%. Numéro de notice : A2003-347 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.06.004 En ligne : https://doi.org/10.1016/j.rse.2003.06.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26427
in Remote sensing of environment > vol 88 n° 3 (15/12/2003) . - pp 309 - 323[article]Classification of wheat crop with multi-temporal images: performance of maximum likelihood and artificial neural networks / C.S. Murthy in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)
[article]
Titre : Classification of wheat crop with multi-temporal images: performance of maximum likelihood and artificial neural networks Type de document : Article/Communication Auteurs : C.S. Murthy, Auteur ; P.V. Raju, Auteur ; K.V.S. Badrinath, Auteur Année de publication : 2003 Article en page(s) : pp 4871 - 4890 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] agriculture
[Termes IGN] analyse diachronique
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] classification par réseau neuronal
[Termes IGN] cultures
[Termes IGN] image multitemporelle
[Termes IGN] neurone artificielRésumé : (Auteur) the need for multi-temporal data analysis for delineation of wheat crop has been demonstrated first. It is found that Maximum Likelihood Classification (MLC) with the composite data of multi-temporal images is limited by the problem of large null set containing crop pixels. Therefore, for effective classification of multi-temporal images, two approaches are evaluated : (1) MLC with different strategies-sequential MLC (s_MLC), MLC with Principal Components (pca_MLC) and iterative MLC (i_MLC) ; and (2) Artificial Neural Network (ANN) with back-propagation method. These classifiers were applied on multi-temporal Indian Remote-Sending satellite (IRS)-1 B images to classify wheat crop in two areas of India, one with dominant wheat and the other with less dominant wheat cultivation. Among the three strategies of MLC, i_MLC has resulted in relatively better classification of wheat. However, the correctness of labelling of wheat pixels. The performance of ANN is proved to be better, in both the situations of dominant wheat and less dominant wheat cultivation. Numéro de notice : A2003-314 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000070490 En ligne : https://doi.org/10.1080/0143116031000070490 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22610
in International Journal of Remote Sensing IJRS > vol 24 n° 23 (December 2003) . - pp 4871 - 4890[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03231 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Training a neural network with a canopy reflectance model to estimate crop leaf area index / F. Mark Danson in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)Permalinkvol 29 n° 6 - 01/12/2003 - Applications de la télédétection en hydrologie (Bulletin de Canadian journal of remote sensing) / R. GrangerPermalinkCombining metric aerial photography and near-infrared videography to define within-field soil sampling frameworks / G.G. Wright in Geocarto international, vol 18 n° 4 (December 2003 - February 2004)PermalinkFast SAR image restoration, segmentation, and detection of high-reflectance regions / E. Bratsolis in IEEE Transactions on geoscience and remote sensing, vol 41 n° 12 (December 2003)PermalinkKnowledge discovery from soil maps using inductive learning / F. Qi in International journal of geographical information science IJGIS, vol 17 n° 8 (december 2003)Permalinkvol 65 n° 6 - November 2003 (Bulletin de Graphical models)PermalinkStatistical and operational performance assessment of multitemporal SAR image filtering / Emmanuel Trouvé in IEEE Transactions on geoscience and remote sensing, vol 41 n° 11 (November 2003)PermalinkStrategies for integrating information from multiple resolutions into land-use/land-cover classification routines / D.M. Chen in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 11 (November 2003)PermalinkBayesian classification by data augmentation / B. Regguzoni in International Journal of Remote Sensing IJRS, vol 24 n° 20 (October 2003)PermalinkData fusion and feature extraction in the wavelet domain / Magnus Orn Ulfarsson in International Journal of Remote Sensing IJRS, vol 24 n° 20 (October 2003)Permalink