Improved SAR image coregistration using pixel-offset series

Journal article (2014)

Authors

Teng Wang King Abdullah University of Science and Technology
Sigurjón Jónsson King Abdullah University of Science and Technology
R.F. Hanssen Mathematical Geodesy and Positioning - CEG
Research Group
Mathematical Geodesy and Positioning (CEG) (TU Delft)
Synthetic aperture radar (SAR) Interferometric SAR (InSAR) Image coregistration Pixel offsets
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Published Date

2014

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Geoscience and Remote Sensing

Research Group

Mathematical Geodesy and Positioning

Abstract

Synthetic aperture radar (SAR) image coregistration is a key procedure before interferometric SAR (InSAR) time-series analysis can be started. However, many geophysical data sets suffer from severe decorrelation problems due to a variety of reasons, making precise coregistration a nontrivial task. Here, we present a new strategy that uses a pixel-offset series of detected subimage patches dominated by point-like targets (PTs) to improve SAR image coregistrations. First, all potentially coherent image pairs are coregistered in a conventional way. In this step, we propose a coregistration quality index for each image to rank its relative 'significance' within the data set and to select a reference image for the SAR data set. Then, a pixel-offset series of detected PTs is made from amplitude maps to improve the geometrical mapping functions. Finally, all images are resampled depending on the pixel offsets calculated from the updated geometrical mapping functions. We used images from a rural region near the North Anatolian Fault in eastern Turkey to test the proposed method, and clear coregistration improvements were found based on amplitude stability. This enhanced the fact that the coregistration strategy should therefore lead to improved InSAR time-series analysis results. © 2014 IEEE.