Reducing patch-like Errors in SAR offset tracking displacements using logarithmic transformation and a weighted NCC algorithm

Pixel offset tracking (OT) algorithm is a useful tool for measuring large surface displacements by matching amplitudes in master and slave synthetic aperture radar (SAR) images. However, strong backscatters can cause homogeneous errors within a matching window (referred to as patch-like errors) in t...

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Bibliographic Details
Published in:Remote sensing letters 2023-04, Vol.14 (4), p.357-368
Main Authors: Niu, Jingjing, Yang, Zefa, Zhang, Lingling, Lu, Jufeng, Xiang, Yucheng, Tian, Zunhua, Guo, Shanshan
Format: Article
Language:English
Subjects:
Algorithms
Amplitudes
Backscattering
Coal mining
coal mining subsidence
Cross correlation
Errors
large displacement
logarithmic transformation
Logarithms
Matching
patch-like errors
Radar imaging
SAR (radar)
SAR offset tracking
Synthetic aperture radar
Tracking
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Summary:Pixel offset tracking (OT) algorithm is a useful tool for measuring large surface displacements by matching amplitudes in master and slave synthetic aperture radar (SAR) images. However, strong backscatters can cause homogeneous errors within a matching window (referred to as patch-like errors) in traditional OT processing, thereby misleading the interpretation of displacement events, especially over a small area. In this letter, we proposed an improved SAR OT algorithm to reduce patch-like errors. In which, a logarithmic transformation was firstly utilized to narrow the SAR amplitude range between strong and weak back scatterers. Strong backscatters causing patch-like errors were then statistically detected with an indicator of median absolute deviation. Finally, those strong backscatters were excluded from SAR OT processing using a weighted normalized cross-correlation scheme, in order to reduce the caused patch-like errors. Two real data tests over the Shuozhou and Yulin coal mining areas, China, suggest that the mean accuracy of the displacements estimated by the presented method improved about 30%, with respect to that estimated by the traditional OT algorithm. The proposed SAR OT algorithm offers a robust option to measure large displacements, especially over a small area, associated with anthropologic or geophysical activities.
ISSN:2150-704X
2150-7058
DOI:10.1080/2150704X.2023.2201381