A comparative study of coherence estimators for interferometric SAR image coregistration and coherent change detection

2019 ◽  
Author(s):  
Horst Hammer ◽  
Antje Thiele ◽  
Fabian Lorenz ◽  
Erich Cadario ◽  
Silvia Kuny ◽  
...  
Keyword(s):  
Comparative Study ◽  
Change Detection ◽  
Sar Image ◽  
Image Coregistration ◽  
Coherent Change Detection ◽  
Interferometric Sar

scholarly journals COHERENT CHANGE DETECTION FOR REPEATED-PASS INTERFEROMETRIC SAR IMAGES: AN APPLICATION TO EARTHQUAKE DAMAGE ASSESSMENT ON BUILDINGS

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 383-388 ◽  
Author(s):  
D. Oxoli ◽  
P. Boccardo ◽  
M. A. Brovelli ◽  
M. E. Molinari ◽  
A. Monti Guarnieri
Keyword(s):  
Change Detection ◽  
Emergency Management ◽  
Performance Assessment ◽  
Damage Assessment ◽  
Earthquake Damage ◽  
Detection Sensitivity ◽  
Management Service ◽  
Sar Images ◽  
Coherent Change Detection ◽  
Interferometric Sar

<p><strong>Abstract.</strong> During disaster response, the availability of relevant information, delivered in a proper format enabling its use among the different actors involved in response efforts, is key to lessen the impact of the disaster itself. Focusing on the contribution of geospatial information, meaningful advances have been achieved through the adoption of satellite earth observations within emergency management practices. Among these technologies, the Synthetic Aperture Radar (SAR) imaging has been extensively employed for large-scale applications such as flood areas delineation and terrain deformation analysis after earthquakes. However, the emerging availability of higher spatial and temporal resolution data has uncovered the potential contribution of SAR to applications at a finer scale. This paper proposes an approach to enable pixel-wise earthquake damage assessments based on Coherent Change Detection methods applied to a stack of repeated-pass interferometric SAR images. A preliminary performance assessment of the procedure is provided by processing Sentinel-1 data stack related to the 2016 central Italy earthquake for the towns of Ametrine and Accumoli. Damage assessment maps from photo-interpretation of high-resolution airborne imagery, produced in the framework of Copernicus EMS (Emergency Management Service &amp;ndash; European Commission) and cross-checked with field survey, is used as ground truth for the performance assessment. Results show the ability of the proposed approach to automatically identify changes at an almost individual building level, thus enabling the possibility to empower traditional damage assessment procedures from optical imagery with the centimetric change detection sensitivity characterizing SAR. The possibility of disseminating outputs in a GIS-like format represents an asset for an effective and cross-cutting information sharing among decision makers and analysts.</p>

scholarly journals Enhancing Coherence Images for Coherent Change Detection: An Example on Vehicle Tracks in Airborne SAR Images

2021 ◽  
Vol 13 (24) ◽  
pp. 5010
Author(s):  
Horst Hammer ◽  
Silvia Kuny ◽  
Antje Thiele
Keyword(s):  
Change Detection ◽  
Sar Interferometry ◽  
Phase Image ◽  
Low Coherence ◽  
Interferometric Phase ◽  
Coherent Change Detection ◽  
Airborne Sar ◽  
Interferometric Sar ◽  
Favorable Conditions ◽  
High Coherence

In Synthetic Aperture Radar (SAR) interferometry, one of the most widely used measures for the quality of the interferometric phase is coherence. However, in favorable conditions coherence can also be used to detect subtle changes on the ground, which are not visible in the amplitude images. For such applications, i.e., coherent change detection, it is important to have a good contrast between the unchanged (high-coherence) parts of the scene and the changed (low-coherence) parts. In this paper, an algorithm is introduced that aims at enhancing this contrast. The enhancement is achieved by a combination of careful filtering of the amplitude images and the interferometric phase image. The algorithm is applied to an airborne interferometric SAR image pair recorded by the SmartRadar experimental sensor of Hensoldt Sensors GmbH. The data were recorded during a measurement campaign over the Bann B installations of POLYGONE Range in southern Rhineland-Palatinate (Germany), with a time gap of approximately four hours between the overflights. In-between the overflights, several vehicles were moved on the site and the goal of this work is to enhance the coherence image such that the tracks of these vehicles can be detected as completely as possible in an automated way. Several coherence estimation schemes found in the literature are explored for the enhancement, as well as several commonly used speckle filters. The results of these filtering steps are evaluated visually and quantitatively, showing that the mean gray-level difference between the low-coherence tracks and their high-coherence surroundings could be enhanced by at least 28%. Line extraction is then applied to the best enhancement. The results show that the tracks can be detected much more completely using the coherence contrast enhancement scheme proposed in this paper.

scholarly journals Neyman-Pearson Criterion-Based Change Detection Methods for Wavelength-Resolution SAR Image Stacks

2021 ◽  
pp. 1-5
Author(s):  
Dimas I. Alves ◽  
Cristian Muller ◽  
Bruna G. Palm ◽  
Mats I. Pettersson ◽  
Viet T. Vu ◽  
...  
Keyword(s):  
Change Detection ◽  
Detection Methods ◽  
Sar Image ◽  
Pearson Criterion ◽  
Wavelength Resolution
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