title   
  

Sparse representation in structured dictionaries with application to synthetic aperture radar

Varshney, Kush R. and Çetin, Müjdat and Fisher, III, John W. and Willsky, Alan S. (2008) Sparse representation in structured dictionaries with application to synthetic aperture radar. IEEE transactions on signal processing, 56 (issue 8, part 1). pp. 3548-3561.

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Official URL: http://dx.doi.org/10.1109/TSP.2008.919392

Abstract

Sparse signal representations and approximations from overcomplete dictionaries have become an invaluable tool recently. In this paper, we develop a new, heuristic, graph-structured, sparse signal representation algorithm for overcomplete dictionaries that can be decomposed into subdictionaries and whose dictionary elements can be arranged in a hierarchy. Around this algorithm, we construct a methodology for advanced image formation in wide-angle synthetic aperture radar (SAR), defining an approach for joint anisotropy characterization and image formation. Additionally, we develop a coordinate descent method for jointly optimizing a parameterized dictionary and recovering a sparse representation using that dictionary. The motivation is to characterize a phenomenon in wide-angle SAR that has not been given much attention before: migratory scattering centers, i.e. scatterers whose apparent spatial location depends on aspect angle. Finally, we address the topic of recovering solutions that are sparse in more than one objective domain by introducing a suitable sparsifying cost function. We encode geometric objectives into SAR image formation through sparsity in two domains, including the normal parameter space of the Hough transform.

Item Type:Article
Uncontrolled Keywords:sparse signal representations, overcomplete dictionaries, optimization methods, tree searching, inverse problems, synthetic aperture radar, Hough transforms
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
ID Code:10481
Deposited By:Müjdat Çetin
Deposited On:11 Nov 2008 13:58
Last Modified:25 May 2011 14:05

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