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Sea ice deformation state from Synthetic Aperture Radar Imagery: part 2 Effects of spatial resolution and noise level / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 46 n° 8 (August 2008)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 46 n° 8 (August 2008) . - pp 2197 - 2207 Titre : Sea ice deformation state from Synthetic Aperture Radar Imagery: part 2 Effects of spatial resolution and noise level Type de document : Article/Communication Auteurs : W. Dierking, Auteur ; J. Dall, Auteur Année de publication : 2008 Article en page(s) : pp 2197 - 2207 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] bande C [Termes IGN] bande L [Termes IGN] filtrage du bruit [Termes IGN] glace de mer [Termes IGN] image aérienne [Termes IGN] image ALOS-PALSAR [Termes IGN] image Envisat-ASAR [Termes IGN] image ERS-SAR [Termes IGN] image radar [Termes IGN] pouvoir de résolution géométrique [Termes IGN] radargrammétrie [Termes IGN] rapport signal sur bruit Résumé : (Auteur) C- and L-band airborne synthetic aperture radar (SAR) imagery acquired at like- and cross-polarizations over sea ice under winter conditions is examined with the objective to study the discrimination between level ice and ice deformation features. High-resolution low-noise data were analyzed in the first paper. In this second paper, the main topics are the effects of spatial resolution and signal-to-noise ratio. Airborne high-resolution SAR scenes are used to generate a sequence of images with increasingly coarser spatial resolution from 5 to 25 m, keeping the number of looks constant. The signal-to-noise ratio is varied between typical noise levels for airborne imagery and satellite data. Areal fraction of deformed ice and average deformation distance are determined for each image product. At L-band, the retrieved values of the areal fraction get larger as the image resolution is degraded. The areal fraction at C-band remains constant. The retrieved average distance between deformation features increases both at C- and L-bands as the image resolution gets coarser. The influence of noise becomes noticeable if its level is equal or larger than the average intensity backscattered from the level ice. The retrieval of deformation parameters using simulated images that resemble ERS-2 SAR, Envisat ASAR, and ALOS PALSAR data products is discussed. Basic differences between real and simulated ERS-2 SAR images are analyzed. Copyright IEEE Numéro de notice : A2008-398 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2008.917267 En ligne : https://doi.org/10.1109/TGRS.2008.917267 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29487 [article]

Voir aussi

• Sea-ice deformation state from synthetic aperture radar imagery: Part 1 comparison of C- and L-band and different polarization / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 45 n° 11 Tome 2 (November 2007)  

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Sea-ice deformation state from synthetic aperture radar imagery: Part 1 comparison of C- and L-band and different polarization / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 45 n° 11 Tome 2 (November 2007)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 45 n° 11 Tome 2 (November 2007) . - pp 3610 - 3622 Titre : Sea-ice deformation state from synthetic aperture radar imagery: Part 1 comparison of C- and L-band and different polarization Type de document : Article/Communication Auteurs : W. Dierking, Auteur ; J. Dall, Auteur Année de publication : 2007 Article en page(s) : pp 3610 - 3622 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse comparative [Termes IGN] bande C [Termes IGN] bande L [Termes IGN] classification dirigée [Termes IGN] glace de mer [Termes IGN] image radar moirée [Termes IGN] polarimétrie radar [Termes IGN] polarisation Résumé : (Auteur) In this paper, we present a quantitative comparison of L- and C-band airborne synthetic aperture radar imagery acquired at like- and cross-polarizations over deformed sea ice under winter conditions. The parameters characterizing the deformation state of the ice are determined at both radar bands and at different polarizations. The separation of deformed and level ice is based on a target detection technique. The threshold is set such that image pixels with intensities equal to or larger than the highest 2% of the level-ice intensity distribution are classified as deformed ice, independent of the radar configuration and ice conditions. Optical imagery of sufficient quality for comparison is available only in a very few cases. To characterize the deformation state, the areal fraction of deformation features and the average distance between these features are evaluated. The values obtained for both parameters are very sensitive to the radar frequency. Aeral fractions are larger, and average distances are smaller at L-band than at C-band because of the much higher intensity contrast between the deformed and level ice at L-band. The differences between polarizations at one radar band are smaller but not always negligible. In comparison to optical images, it was observed that deformed-ice areas can be distinguished from level ice over their whole length and exten-sion at L-band, whereas at C-band, often, only prominent parts are visible. Numéro de notice : A2007-508 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2007.903711 En ligne : https://doi.org/10.1109/TGRS.2007.903711 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28871 [article]

Voir aussi

• Sea ice deformation state from Synthetic Aperture Radar Imagery: part 2 Effects of spatial resolution and noise level / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 46 n° 8 (August 2008)  

Exemplaires(1)

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065-07111B	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Agriculture classification using PolSAR data / H. Skriver (2005)

Public Titre : Agriculture classification using PolSAR data Type de document : Article/Communication Auteurs : H. Skriver, Auteur ; J. Dall, Auteur ; Thuy Le Toan, Auteur ; et al., Auteur Editeur : Noordwijk : ESA Publications Année de publication : 2005 Collection : ESA Specialist Panel, ISSN 0379-6566 num. 586 Conférence : POLinSAR 2005 17/01/2005 21/01/2005 Frascati Italie Importance : 6 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse discriminante [Termes IGN] céréales [Termes IGN] classification à base de connaissances [Termes IGN] classification dirigée [Termes IGN] cultures [Termes IGN] données polarimétriques [Termes IGN] image EMISAR [Termes IGN] image radar moirée [Termes IGN] polarimétrie radar [Termes IGN] polarisation Résumé : (Auteur) In this paper a classification scheme is presented, that uses a knowledge-based approach, where the crops are first classified into broad classes, i.e. bare surfaces, cereal crops, root crops, spring crops, winter crops etc. Hereafter, the discrimination between the individual crop types within these broad categories is performed. The discrimination into the broad classes is performed using standard polarimetric parameters such as the backscatter coefficients both at linear and circular polarisations, correlation coefficient and phase difference. The classification into the individual crop types is possible for some of the crop types, whereas it may for instance be very difficult to discriminate between some of the cereal crops. This part of the classification process is not as well established as the first part, and both a supervised approach and a knowledge-based approach may be used. Both POLSAR and PolInSAR data may be included in the classification scheme. The classification approach has been evaluated using data from the Danish EMISAR, and quantitative results based on in-situ information are presented. Numéro de notice : 13686 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Communication DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=64268