Descripteur
Documents disponibles dans cette catégorie (986)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Novasar: space-based radar for all / D. Willetts in GEO: Geoconnexion international, vol 11 n° 6 (june 2012)
[article]
Titre : Novasar: space-based radar for all Type de document : Article/Communication Auteurs : D. Willetts, Auteur Année de publication : 2012 Article en page(s) : pp 33 - 35 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] capteur imageur
[Termes IGN] capteur spatial
[Termes IGN] image radar moirée
[Termes IGN] radar à antenne synthétiqueRésumé : (Auteur) With ability to acquire data at a fraction of the cost of the conventional synthetic aperture radar sensors, NovaSar looks to support a wide variety of civil applications. Numéro de notice : A2012-272 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31718
in GEO: Geoconnexion international > vol 11 n° 6 (june 2012) . - pp 33 - 35[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 062-2012061 SL Revue Centre de documentation Revues en salle Disponible Evaluation of bayesian despeckling and texture extraction methods based on Gauss–Markov and auto-binomial gibbs random fields: Application to TerraSAR-X data / D. Espinoza Molina in IEEE Transactions on geoscience and remote sensing, vol 50 n° 5 Tome 2 (May 2012)
[article]
Titre : Evaluation of bayesian despeckling and texture extraction methods based on Gauss–Markov and auto-binomial gibbs random fields: Application to TerraSAR-X data Type de document : Article/Communication Auteurs : D. Espinoza Molina, Auteur ; D. Gleich, Auteur ; M. Dactu, Auteur Année de publication : 2012 Article en page(s) : pp 2001 - 2025 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] analyse comparative
[Termes IGN] analyse texturale
[Termes IGN] champ aléatoire de Markov
[Termes IGN] échantillonnage de Gibbs
[Termes IGN] évaluation
[Termes IGN] filtre de déchatoiement
[Termes IGN] image radar moirée
[Termes IGN] image TerraSAR-X
[Termes IGN] inférence statistique
[Termes IGN] texture d'imageRésumé : (Auteur) Speckle hinders information in synthetic aperture radar (SAR) images and makes automatic information extraction very difficult. The Bayesian approach allows us to perform the despeckling of an image while preserving its texture and structures. This model-based approach relies on a prior model of the scene. This paper presents an evaluation of two despeckling and texture extraction model-based methods using the two levels of Bayesian inference. The first method uses a Gauss-Markov random field as prior, and the second is based on an auto-binomial model (ABM). Both methods calculate a maximum a posteriori and determine the best model using an evidence maximization algorithm. Our evaluation approach assesses the quality of the image by means of the despeckling and texture extraction qualities. The proposed objective measures are used to quantify the despeckling performances of these methods. The accuracy of modeling and characterization of texture were determined using both supervised and unsupervised classifications, and confusion matrices. Real and simulated SAR data were used during the validation procedure. The results show that both methods enhance the image during the despeckling process. The ABM is superior regarding texture extraction and despeckling for real SAR images. Numéro de notice : A2012-190 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2169679 En ligne : https://doi.org/10.1109/TGRS.2011.2169679 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31637
in IEEE Transactions on geoscience and remote sensing > vol 50 n° 5 Tome 2 (May 2012) . - pp 2001 - 2025[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2012051B RAB Revue Centre de documentation En réserve L003 Disponible Ionospheric artifacts in simultaneous L-band InSAR and GPS observations / J. Chen in IEEE Transactions on geoscience and remote sensing, vol 50 n° 4 (April 2012)
[article]
Titre : Ionospheric artifacts in simultaneous L-band InSAR and GPS observations Type de document : Article/Communication Auteurs : J. Chen, Auteur ; H. Zebker, Auteur Année de publication : 2012 Article en page(s) : pp 11227 - 1239 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] artefact
[Termes IGN] bande L
[Termes IGN] image ALOS-PALSAR
[Termes IGN] image radar moirée
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] propagation ionosphérique
[Termes IGN] teneur totale en électronsRésumé : (Auteur) Phase artifacts in interferometric synthetic aperture radar (InSAR) images frequently degrade the interpretability of the phase and correlation signatures of terrain. Often, these distortions are attributed to spatially variable ionospheric propagation delays at two different SAR acquisition times. We present here L-band InSAR data from Iceland, California, and Hawaii. The California and Hawaii interferograms show no significant ionospheric artifacts, while the Iceland interferogram shows a maximum misregistration of three pixels in the azimuth direction, which leads to severe phase decorrelation artifacts in the InSAR image. We relate the misregistration of complex pixels seen in the interferograms to the gradient of the ionospheric total electron content (TEC) observed by global positioning system (GPS) data and confirm that indeed the phase artifacts in the Iceland interferogram are due to dispersive ionospheric propagation rather than other decorrelation factors such as neutral atmospheric delays. We develop a method to measure the spatial TEC variation at synthetic aperture length scales using dual-frequency GPS carrier phase data. We solve for the GPS data ambiguities using a low-resolution ionosphere reference derived from either available ionospheric observations or the GPS carrier phase data themselves. GPS observations show directly the level of ionospheric variability, and the spatial TEC gradient as observed by GPS predicts the misregistration of complex pixels in interferograms in all three areas. This confirmation of the cause of the image artifacts suggests that they can be routinely corrected from the InSAR data alone, provided that the sensor measures the change in TEC along the radar swath. Numéro de notice : A2012-136 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2164805 Date de publication en ligne : 06/10/2011 En ligne : https://doi.org/10.1109/TGRS.2011.2164805 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31584
in IEEE Transactions on geoscience and remote sensing > vol 50 n° 4 (April 2012) . - pp 11227 - 1239[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2012041 RAB Revue Centre de documentation En réserve L003 Disponible Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series / D. Small in Journal of geodesy, vol 86 n° 4 (April 2012)
[article]
Titre : Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series Type de document : Article/Communication Auteurs : D. Small, Auteur ; A. Schubert, Auteur ; G. Jehle, Auteur ; E. Meier, Auteur Année de publication : 2012 Article en page(s) : pp 257 - 270 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] coin réflecteur
[Termes IGN] GPS en mode différentiel
[Termes IGN] image radar moirée
[Termes IGN] image TerraSAR-X
[Termes IGN] marée terrestre
[Termes IGN] précision géométrique (imagerie)
[Termes IGN] réfraction atmosphérique
[Termes IGN] série temporelleRésumé : (Auteur) The TerraSAR-X (TSX) synthetic aperture radar (SAR) marks the recent emergence of a new generation of spaceborne radar sensors that can for the first time lay claim to localization accuracies in the sub-meter range. The TSX platform’s extremely high orbital stability and the sensor’s hardware timing accuracy combine to enable direct measurements of atmospheric refraction and solid Earth movements. By modeling these effects for individual TSX acquisitions, absolute pixel geolocation accuracy on the order of several centimeters can be achieved without need for even a single tiepoint. A 16-month time series of images was obtained over a fixed test site, making it possible to validate both an atmospheric refraction and a solid Earth tide model, while at the same time establishing the instrument’s long-term stability. These related goals were achieved by placing trihedral corner reflectors (CRs) at the test site and estimating their phase centers with centimeter-level accuracy using differential GPS (DGPS). Oriented in pairs toward a given satellite track, the CRs could be seen as bright “points” in the images, providing a geometric reference set. SAR images from the high-resolution spotlight (HS) mode were obtained in alternating ascending and descending orbit configurations. The highest-resolution products were selected for their small sample dimensions, as positions can be more precisely determined. Based on the delivered product annotations, the CR image positions were predicted, and these predictions were compared with their measured image positions both before and after compensation for atmospheric refraction and systematic solid Earth deviations. It was possible to show that when the atmospheric distortion and Earth tides are taken into account, the TSX HS products have geolocation accuracies far exceeding the specified requirements. Furthermore, this accuracy was maintained for the duration of the 16-month test period. It could be demonstrated that with a correctly calibrated sensor, and after accounting for atmospheric and tidal effects, tiepoint-free geolocation is possible with TSX with an absolute product accuracy of about 5 cm. Numéro de notice : A2012-204 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0515-6 Date de publication en ligne : 24/09/2011 En ligne : https://doi.org/10.1007/s00190-011-0515-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31651
in Journal of geodesy > vol 86 n° 4 (April 2012) . - pp 257 - 270[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2012041 RAB Revue Centre de documentation En réserve L003 Disponible Potential of texture measurements of two-date dual polarization PALSAR data for the improvement of forest biomass estimation / M. Sarker in ISPRS Journal of photogrammetry and remote sensing, vol 69 (April 2012)
[article]
Titre : Potential of texture measurements of two-date dual polarization PALSAR data for the improvement of forest biomass estimation Type de document : Article/Communication Auteurs : M. Sarker, Auteur ; J. Nichol, Auteur ; B. Ahmad, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 146 - 166 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] biomasse
[Termes IGN] Hong-Kong
[Termes IGN] image ALOS-PALSAR
[Termes IGN] image radar moirée
[Termes IGN] polarimétrie radar
[Termes IGN] polarisation
[Termes IGN] texture d'imageRésumé : (Auteur) The recently available space-borne SAR sensor, PALSAR, is more promising than its predecessor JERS-1 for biomass estimation because of its long wavelength (L-band), and its ability to provide data with different polarizations, varying incidence angles and higher spatial resolutions. This research investigates the potential of two-date dual polarization (HH and HV) SAR imagery for biomass estimation using different kinds of texture processing and different combinations of single and dual polarization ratios. The investigation is conducted in a mountainous, sub-tropical study area where biomass levels are far beyond the previously recognized saturation levels for L-band SAR images, and forest is a mixture of native and non-native species and plantations. We analyzed two-date SAR data with four steps of image processing, including raw data processing in various combinations, texture measurement parameters of HH and HV polarizations, texture measurement parameters of HH and HV together (both jointly and as a ratio), and a ratio of two-date texture parameters along with a single and two-date ratio. When the processed images were compared with ground data from 50 plots, the performance from raw data processing was low, with adjusted r2 = 0.22, but after all four processing steps, promising model accuracy (adjusted r2 = 0.90 and RMSE = 28.58 t/ha) and validation accuracy (using the Leave-One-Out-Cross-Validation) with adjusted r2 = 0.88 and RMSE = 35.69 t/ha, were achieved from the combination of single- and two-date polarization ratios of texture parameters. The strong performance achieved indicates that L-band dual-polarization (HH and HV) SAR data from PALSAR has great potential for biomass estimation, far beyond the previously reported L-band saturation point for biomass. This result is attributed to the synergy among texture processing and dual polarization on the one hand, which were able to average out random speckle noise, and the use of ratio instead of absolute quantities, due to its well known ability to reduce forest structural and terrain effects. The additional use of two-date SAR data with these processing techniques was able to add complementary information derived from biomass response in both wet and dry seasons. Thus overall, undesirable image noise and terrain effects were reduced. Numéro de notice : A2012-198 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2012.03.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.03.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31645
in ISPRS Journal of photogrammetry and remote sensing > vol 69 (April 2012) . - pp 146 - 166[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2012031 SL Revue Centre de documentation Revues en salle Disponible Satellite SAR geocoding with refined RPC model / L. Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 69 (April 2012)PermalinkUsing multi-frequency radar and discrete-return LiDAR measurements to estimate above-ground biomass and biomass components in a coastal temperate forest / O. Tsui in ISPRS Journal of photogrammetry and remote sensing, vol 69 (April 2012)PermalinkApplication of RPC model in orthorectification of spaceborne SAR imagery / G. Zhang in Photogrammetric record, vol 27 n° 137 (March - May 2012)PermalinkCharacterization of forests and deforestation in Cambodia using ALOS/PALSAR observation / R. Avtar in Geocarto international, vol 27 n° 2 (March 2012)PermalinkEvaluation of modified four-component scattering power decomposition method over highly rugged glaciated terrain / G. Singh in Geocarto international, vol 27 n° 2 (March 2012)PermalinkMarkov Chain CFAR detection for polarimetric data using data fusion / C. Fei in IEEE Transactions on geoscience and remote sensing, vol 50 n° 2 (February 2012)PermalinkA nonlocal SAR image denoising algorithm based on LLMMSE wavelet shrinkage / S. Parrilli in IEEE Transactions on geoscience and remote sensing, vol 50 n° 2 (February 2012)PermalinkA simple and robust feature point matching algorithm based on restricted spatial order constraints for aerial image registration / Z. Liu in IEEE Transactions on geoscience and remote sensing, vol 50 n° 2 (February 2012)PermalinkUsefulness of synthetic aperture radar (SAR) interferometry for digital elevation model (DEM) generation and estimation of land surface displacement in Jharia coal field area / Atanu Bhattacharya in Geocarto international, vol 27 n° 1 (February 2012)PermalinkGénération et qualification de modèles numériques de surface de haute résolution spatiale par interférométrie radar à synthèse d'ouverture / Paul Landel (2012)Permalink