Sparsity-driven coupled imaging and autofocusing for interferometric SAR

Zengin, Oğuzcan and Khwaja, Ahmed Shaharyar and Çetin, Müjdat (2018) Sparsity-driven coupled imaging and autofocusing for interferometric SAR. In: Algorithms for Synthetic Aperture Radar Imagery XXV 2018, Orlando, FL, USA

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We propose a sparsity-driven method for coupled image formation and autofocusing based on multi-channel data collected in interferometric synthetic aperture radar (IfSAR). Relative phase between SAR images contains valuable information. For example, it can be used to estimate the height of the scene in SAR interferometry. However, this relative phase could be degraded when independent enhancement methods are used over SAR image pairs. Previously, Ramakrishnan et al. proposed a coupled multi-channel image enhancement technique, based on a dual descent method, which exhibits better performance in phase preservation compared to independent enhancement methods. Their work involves a coupled optimization formulation that uses a sparsity enforcing penalty term as well as a constraint tying the multichannel images together to preserve the cross-channel information. In addition to independent enhancement, the relative phase between the acquisitions can be degraded due to other factors as well, such as platform location uncertainties, leading to phase errors in the data and defocusing in the formed imagery. The performance of airborne SAR systems can be affected severely by such errors. We propose an optimization formulation that combines Ramakrishnan et al.'s coupled IfSAR enhancement method with the sparsity-driven autofocus (SDA) approach of Önhon and Çetin to alleviate the effects of phase errors due to motion errors in the context of IfSAR imaging. Our method solves the joint optimization problem with a Lagrangian optimization method iteratively. In our preliminary experimental analysis, we have obtained results of our method on synthetic SAR images and compared its performance to existing methods.
Item Type: Papers in Conference Proceedings
Uncontrolled Keywords: autofocus; compressed sensing; Computational imaging; interferometry; multi-channel imaging; phase errors; sparsity; synthetic aperture radar
Divisions: Faculty of Engineering and Natural Sciences
Depositing User: Müjdat Çetin
Date Deposited: 27 May 2023 22:03
Last Modified: 27 May 2023 22:03

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