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Auteur Andreas Kääb |
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Precise DEM extraction from Svalbard using 1936 high oblique imagery / Luc Girod in Geoscientific instrumentation methods and data systems, vol 7 n° 4 ([01/10/2018])
[article]
Titre : Precise DEM extraction from Svalbard using 1936 high oblique imagery Type de document : Article/Communication Auteurs : Luc Girod , Auteur ; Niels Ivar Nielsen, Auteur ; Frédérique Couderette, Auteur ; Christopher Nuth, Auteur ; Andreas Kääb, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 277 - 288 Note générale : bibliographie
The study was funded by the European Research Council under the European Union's Seventh Framework Program (FP/2007-2013)/ERC grant agreement no. 320816 and the ESA projects Glaciers_cci (4000109873/14/I-NB), DUE GlobPermafrost (4000116196/15/IN-B), and CCI_Permafrost (4000123681/18/I-NB).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] image aérienne oblique
[Termes IGN] MicMac
[Termes IGN] modèle numérique de surface
[Termes IGN] photographie aérienne oblique
[Termes IGN] Python (langage de programmation)
[Termes IGN] structure-from-motion
[Termes IGN] Svalbard
[Termes IGN] zone polaireRésumé : (auteur) Stretching time series further in the past with the best possible accuracy is essential to the understanding of climate change impacts and geomorphological processes evolving on decadal-scale time spans. In the first half of the twentieth century, large parts of the polar regions were still unmapped or only superficially so. To create cartographic data, a number of historic photogrammetric campaigns were conducted using oblique imagery, which is easier to work with in unmapped environments as collocating images is an easier task for the human eye given a more familiar viewing angle and a larger field of view. Even if the data obtained from such campaigns gave a good baseline for the mapping of the area, the precision and accuracy are to be considered with caution. Exploiting the possibilities arising from modern image processing tools and reprocessing the archives to obtain better data is therefore a task worth the effort. The oblique angle of view of the data is offering a challenge to classical photogrammetric tools, but the use of modern structure-from-motion (SfM) photogrammetry offers an efficient and quantitative way to process these data into terrain models. In this paper, we propose a good practice method for processing historical oblique imagery using free and open source software (MicMac and Python) and illustrate the process using images of the Svalbard archipelago acquired in 1936 by the Norwegian Polar Institute. On these data, our workflow provides 5 m resolution, high-quality elevation data (SD 2 m for moderate terrain) as well as orthoimages that allow for the reliable quantification of terrain change when compared to more modern data. Numéro de notice : A2018-661 Affiliation des auteurs : ENSG+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/gi-7-277-2018 Date de publication en ligne : 15/10/2018 En ligne : http://dx.doi.org/10.5194/gi-7-277-2018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93842
in Geoscientific instrumentation methods and data systems > vol 7 n° 4 [01/10/2018] . - pp 277 - 288[article]Documents numériques
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Precise DEM extraction from Svalbard ... - pdf éditeurAdobe Acrobat PDF Glacier surface velocity estimation using repeat TerraSAR-X images: Wavelet- vs. correlation-based image matching / Adrian Schubert in ISPRS Journal of photogrammetry and remote sensing, vol 82 (August 2013)
[article]
Titre : Glacier surface velocity estimation using repeat TerraSAR-X images: Wavelet- vs. correlation-based image matching Type de document : Article/Communication Auteurs : Adrian Schubert, Auteur ; Annina Faes, Auteur ; Andreas Kääb, Auteur ; Erich Meier, Auteur Année de publication : 2013 Article en page(s) : pp 49 - 62 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] analyse comparative
[Termes IGN] appariement d'images
[Termes IGN] corrélation
[Termes IGN] glacier
[Termes IGN] image radar moirée
[Termes IGN] image TerraSAR-X
[Termes IGN] ondelette
[Termes IGN] Suisse
[Termes IGN] surveillance écologique
[Termes IGN] vitesseRésumé : (Auteur) For the observation and monitoring of glacier surface velocity (GSV), remote sensing is an increasingly suitable tool thanks to the high temporal and spatial resolution of the data. Radar sensors have the specific advantage over optical sensors of being nearly weather and time-independent. Two image pairs separated by 11 days, acquired with the high-resolution spotlight (HS) and stripmap (SM) modes of the German sensor TerraSAR-X, were used to estimate GSV over Switzerland’s Aletsch Glacier. The SM mode covers larger ground swaths, making it more suitable for glacier-wide observations, while the HS images cover less area but offer the highest-possible spatial resolution, approximately 1x1 m on the ground. The images were acquired during the summer to maximise feature visibility by minimal snow cover. GSV estimation was performed using two methods, the comparison of which was a major goal of this study: traditional cross-correlation optimisation and a dense image matching algorithm based on complex wavelet decomposition. Each method was found to have unique advantages and disadvantages, but it was concluded that for GSV monitoring, cross-correlation is probably preferable to the wavelet-based approach. While it generates fewer estimates per unit area, this is not necessarily a critical requirement for all glaciological applications, and the method requires less initial “tuning” (calibration) than the wavelet algorithm, making it a slightly better tool in operational contexts. Also, the use of the highest-resolution spotlight datasets is recommended over stripmap mode images when large-area coverage is less critical. The comparative lack of visible features at the resolution of the stripmap images made reliable GSV estimation difficult, with the exception of several small areas dominated by large crevasses. Numéro de notice : A2013-411 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.04.010 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.04.010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32549
in ISPRS Journal of photogrammetry and remote sensing > vol 82 (August 2013) . - pp 49 - 62[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2013081 RAB Revue Centre de documentation En réserve L003 Disponible Detecting and quantifying mountain permafrost creep from in situ inventory, space-borne radar interferometry and airborne digital photogrammetry / Tazio Strozzi in International Journal of Remote Sensing IJRS, vol 25 n° 15 (August 2004)
[article]
Titre : Detecting and quantifying mountain permafrost creep from in situ inventory, space-borne radar interferometry and airborne digital photogrammetry Type de document : Article/Communication Auteurs : Tazio Strozzi, Auteur ; Andreas Kääb, Auteur Année de publication : 2004 Article en page(s) : pp 2919 - 2931 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image mixte
[Termes IGN] analyse comparative
[Termes IGN] données de terrain
[Termes IGN] glacier
[Termes IGN] image aérienne
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] mouvement de terrain
[Termes IGN] pergélisol
[Termes IGN] photo-interprétationRésumé : (Auteur) In this paper three different techniques for detecting and quantifying mountain permafrost creep are compared: (1) rock glacier inventory and characterization from in situ indicators, (2) space-borne radar interferometry, and (3) digital processing of repeated airborne imagery. The specific characteristics of the three methods and their complementarity are investigated for the Fletschhorn mountain range in the Simplon/Saas valley region, Swiss Alps. We found that radar interferometry is suitable to quantify the degree of activity and the order of surface velocity of rock glaciers over large areas in one process, with the possibility to also detect very small movements of inactive and relict rock glaciers. On the other hand, aero-photogrammetry represents a valuable base for additional interpretation of the three-dimensional surface flow field (including speed, direction and change in thickness) of the most active rock glaciers. Results from radar interferometry can also form the basis for further detailed in situ investigations. Numéro de notice : A2004-296 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116042000192330 En ligne : https://doi.org/10.1080/0143116042000192330 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26823
in International Journal of Remote Sensing IJRS > vol 25 n° 15 (August 2004) . - pp 2919 - 2931[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04131 RAB Revue Centre de documentation En réserve L003 Exclu du prêt