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Temporal Stacking of Cross-Correlation for Glacier Offset Tracking

Li, Shiyi und Bernhard, Philipp und Hajnsek, Irena und Leinss, Silvan (2020) Temporal Stacking of Cross-Correlation for Glacier Offset Tracking. In: EGUsphere, 7348. Copernicus GmbH. EGU General Assembly 2020, 2020-05-04 - 2020-05-08, Vienna, Austria. doi: 10.5194/egusphere-egu2020-7348.

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Offizielle URL: https://www.research-collection.ethz.ch/handle/20.500.11850/453641

Kurzfassung

Offset tracking is one of the most widely applied methods for measuring glacier flow velocities using remote sensing data. It uses the pair-wise cross-correlation of images acquired at two different times to detect offsets between image templates of a certain size. Despite the simplicity and reliability of the method, accurate estimations of glacier velocities are limited by the accountability of features and the noise, e.g. radar speckles in synthetic aperture radar (SAR) images. One way of gaining robust estimations is to increase the size of image templates, but the resolution of obtained velocity field is inevitably depreciate. Furthermore, for templates that only contain extremely weak features with respect to the noise, increasing the size of templates is not helpful as the noise is boosted more than the features. To overcome these issues, we propose a temporal stacking algorithm that first averages a time series of local cross-correlation functions calculated from a series of consecutive image pairs, and then estimates the averaged velocity from the stacked cross-correlation functions. Assuming the flow velocity of a glacier is constant during a certain time span (e.g. a season), the offsets between consecutive image pairs in the time series ought to be equal. Therefore, the cross-correlation functions can be considered as a time series of signals that record the identical offsets and thus are temporally coherent. Hence, we can temporally stack the signals to enhance the signal-tonoise ratio (SNR) of cross-correlation functions and better estimate offsets from the stacked crosscorrelation functions. The proposed algorithm is assessed by mapping the flow velocity of the Aletsch Glacier using a time series of about 10 SAR images acquired by TanDEM-X in 2017 with constant revisit time of 11 days. The results show that temporal stacking of cross-correlation functions significantly enhances the spatial coverage and resolution of the obtained velocity fields compared to standard offset tracking using only pair-wise cross-correlation functions. This algorithm promotes the ability of mapping glacier velocities to a new extent with larger spatial coverage and higher spatial resolution, and provides a new perspective of measuring glacier velocities through exploiting the emerging time series data from recent high resolution space-born imaging sensors.

elib-URL des Eintrags:https://elib.dlr.de/141235/
Dokumentart:Konferenzbeitrag (Vortrag)
Titel:Temporal Stacking of Cross-Correlation for Glacier Offset Tracking
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Li, ShiyiETH ZürichNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Bernhard, PhilippETH ZürichNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Hajnsek, IrenaDLR-HR, ETH ZurichNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Leinss, SilvanETH ZürichNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:29 November 2020
Erschienen in:EGUsphere
Referierte Publikation:Nein
Open Access:Nein
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Band:7348
DOI:10.5194/egusphere-egu2020-7348
Verlag:Copernicus GmbH
Name der Reihe:EGUsphere
Status:veröffentlicht
Stichwörter:Offset tracking, glacier flow velocities, synthetic aperture radar, SAR
Veranstaltungstitel:EGU General Assembly 2020
Veranstaltungsort:Vienna, Austria
Veranstaltungsart:internationale Konferenz
Veranstaltungsbeginn:4 Mai 2020
Veranstaltungsende:8 Mai 2020
Veranstalter :EGU
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt
HGF - Programmthema:Erdbeobachtung
DLR - Schwerpunkt:Raumfahrt
DLR - Forschungsgebiet:R EO - Erdbeobachtung
DLR - Teilgebiet (Projekt, Vorhaben):R - Sicherheitsrelevante Erdbeobachtung
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Hochfrequenztechnik und Radarsysteme > Radarkonzepte
Hinterlegt von: Radzuweit, Sibylle
Hinterlegt am:05 Mär 2021 10:14
Letzte Änderung:24 Apr 2024 20:41

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