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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

Sea ice monitoring by L-band SAR: an assessment based on literature and comparisons of JERS-1 and ERS-1 imagery / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 44 n° 4 (April 2006)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 44 n° 4 (April 2006) . - pp 957 - 970 Titre : Sea ice monitoring by L-band SAR: an assessment based on literature and comparisons of JERS-1 and ERS-1 imagery Type de document : Article/Communication Auteurs : W. Dierking, Auteur ; T. Busche, Auteur Année de publication : 2006 Article en page(s) : pp 957 - 970 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse comparative [Termes IGN] analyse diachronique [Termes IGN] angle d'incidence [Termes IGN] Arctique [Termes IGN] bande L [Termes IGN] diffusomètre [Termes IGN] glace de mer [Termes IGN] Groenland [Termes IGN] image ERS-SAR [Termes IGN] image JERS [Termes IGN] polarisation [Termes IGN] surveillance hydrologique [Termes IGN] Svalbard [Termes IGN] zone polaire Résumé : (Auteur) Spaceborne single-polarization C-band synthetic aperture radar (SAR) imagery is widely used to gather information about the state of the sea ice cover in the polar regions. C-band is regarded as a reasonable choice for all-season monitoring capabilities. For specific mapping tasks, however, other frequency hands can be more suitable. In the first part of this paper, the summary of a literature study dealing with the utilization of L-band SAR imagery for sea ice monitoring is presented. Investigations reveal that if deformation features such as ice ridges, rubble fields, and brash ice are to be mapped, L-band radar is superior in a number of cases. The second part of this paper addresses the comparison of JERS-1 and ERS-1 SAR images that were acquired over sea ice east of Svalbard and along the east coast of Greenland. The effects of the different frequencies, polarizations, and incidence angles of the two SAR Systems are discussed. It is demonstrated that the images of both sensors complement one another in the analysis of ice conditions, resulting in a more detailed view of the sea ice cover state. Copyright IEEE Numéro de notice : A2006-211 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2005.861745 En ligne : https://doi.org/10.1109/TGRS.2005.861745 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27938 [article]

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065-06041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Change detection for thematic mapping by means of airborne multitemporal polarimetric SAR imagery / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 40 n° 3 (March 2002)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 40 n° 3 (March 2002) . - pp 618 - 636 Titre : Change detection for thematic mapping by means of airborne multitemporal polarimetric SAR imagery Type de document : Article/Communication Auteurs : W. Dierking, Auteur ; H. Skriver, Auteur Année de publication : 2002 Article en page(s) : pp 618 - 636 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] bande C [Termes IGN] bande L [Termes IGN] carte thématique [Termes IGN] chatoiement [Termes IGN] détection de changement [Termes IGN] image radar [Termes IGN] image radar moirée [Termes IGN] polarimétrie [Termes IGN] seuillage d'image Résumé : (Auteur) The paper addresses the detection of changes in multitemporal polarimetric radar images, focusing on small objects and narrow linear features. The images were acquired at C- and L-band by the airborne EMISAR system. It is found that the radar intensities are better suited for change detection than the correlation coefficient and the phase difference between the co-polarized channels. In the case of linear features, there is no obvious difference between C- and L-band, and slight variations of the flight tracks are acceptable at look angles larger than 35 degrees. Theoretical detection thresholds are evaluated from the statistical distribution of the intensity ratio due to speckle. For the linear features and for urban environments, the observed thresholds are larger than the theoretical predictions. This is interpreted as an effect of radar intensity variations on length scales smaller than the spatial image resolution. The signature of urban areas is very sensitive to deviations between the flight tracks, and the sensitivity is larger at C-band than at L-band. On the other hand, the intensity contrast between buildings and the urban background is smaller at L-band and larger at C-band. For change detection, thresholds may have to be chosen separately for each object class because the intensity ratios of different object classes vary differently as a function of time. Numéro de notice : A2002-176 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2002.1000322 En ligne : https://ieeexplore.ieee.org/document/1000322 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22091 [article]

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065-02031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
065-02032	RAB	Revue	Centre de documentation	En réserve L003	Disponible