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A phase signature for detecting wet subsurface structures using polarimetric L-band SAR / Y. Lasne in IEEE Transactions on geoscience and remote sensing, vol 42 n° 8 (August 2004)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 42 n° 8 (August 2004) . - pp 1683 - 1694 Titre : A phase signature for detecting wet subsurface structures using polarimetric L-band SAR Type de document : Article/Communication Auteurs : Y. Lasne, Auteur ; P. Paillou, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 1683 - 1694 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] bande L [Termes IGN] dune [Termes IGN] eau souterraine [Termes IGN] équation intégrale [Termes IGN] humidité du sol [Termes IGN] image AIRSAR [Termes IGN] paléosol [Termes IGN] phase [Termes IGN] sable [Termes IGN] simulation numérique [Termes IGN] traitement du signal [Termes IGN] zone aride Résumé : (Auteur) In this paper, we investigate the ability of L-band synthetic aperture radar (SAR) systems to penetrate soils to retrieve information about subsurface wet structures. Our experiment site, the Pyla dune, is a bare sandy area allowing high radar penetration and known to have large wet subsurface structures (paleosoils) at varying depths. Buried paleosoils, which act as moisture tanks, are detectable with radar, since they present a high permittivity due to their water content. By analyzing airborne polarimetric SAR data, we established that a phase signature is correlated to the buried wet palesoils: a phase difference of 23° between the horizontal (HH) and vertical (V V) channels was clearly observed. It allows detection of the paleosoil down to a larger depth (5.2 m) than when only considering HH and HV amplitude signals (3.5 m). In order to confirm this result, field measurements were performed that led to the same observed phase difference. We could fit our observations to the semiempirical model proposed by Oh and Sarabandi, and we reproduced the observed phenomenon using a two-layer integral equation method (IEM) model of the Pyla dune, which was completed by finite-difference time-domain (FDTD) numerical simulations. We show that the soil moisture significantly influences the radar response in terms of phase difference between the copolarised modes. Our study also shows that the single-scattering IEM model reproduces the observed phase difference fairly well for a natural outdoor site when combined to FDTD simulation results. This phase signature could be used as a new tool to map subsurface moisture in arid regions. Numéro de notice : A2004-428 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2004.830645 En ligne : https://doi.org/10.1109/TGRS.2004.830645 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26955 [article]

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065-04081	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Radar stereo- and interferometry-derived digital elevation models: comparison and combination using Radarsat and ERS-2 imagery / M. Gelautz in International Journal of Remote Sensing IJRS, vol 24 n° 24 (December 2003)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 24 n° 24 (December 2003) . - pp 5243 - 5264 Titre : Radar stereo- and interferometry-derived digital elevation models: comparison and combination using Radarsat and ERS-2 imagery Type de document : Article/Communication Auteurs : M. Gelautz, Auteur ; P. Paillou, Auteur ; C.W. Chen, Auteur ; H. Zebker, Auteur Année de publication : 2003 Article en page(s) : pp 5243 - 5264 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] acquisition d'images [Termes IGN] analyse comparative [Termes IGN] histogramme [Termes IGN] image ERS-SAR [Termes IGN] image Radarsat [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] modèle numérique de surface [Termes IGN] modèle stéréoscopique [Termes IGN] pente Résumé : (Auteur) In this experiment, we derive and compare radar stereo and interferometric digital elevation models (DEMs) of a study site in Djibouti, East Africa. A Radarsat stereo pair, as well as Radarsat and ERS-2 interferometric data, comprise the test images. The primary objective of the study was to analyse and compare the results obtained by the two techniques and explore possible synergisms between them. We find that in regions of high coherence, the DEMs produced by interferometry are of much better quality than the stereo result. However, the corresponding error histograms also show some pronounced errors due to decorrelation and phase-unwrapping problems on forested mountain slopes. On the other hand, the more robust stereo reconstruction, with an error standard deviation of 45m, is able to capture the general terrain shape, although finer ' surface details are lost. In the second part of our experiment, we demonstrate that merging the stereoscopic and interferometric DEMs by applying a user-defined weighting function to a filtered coherence map can significantly improve the accuracy of the computed elevation maps Numéro de notice : A2003-343 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115139 En ligne : https://doi.org/10.1080/0143116031000115139 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22638 [article]

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080-03241	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt