Details

Autor(en) / Beteiligte

• Varshney, K.R.
• Cetin, M.
• Fisher, J.W.
• Willsky, A.S.

Titel

Sparse Representation in Structured Dictionaries With Application to Synthetic Aperture Radar

Ist Teil von

• IEEE transactions on signal processing, 2008-08, Vol.56 (8), p.3548-3561

Ort / Verlag

New York, NY: IEEE

Erscheinungsjahr

2008

Quelle

IEEE Electronic Library (IEL)

Beschreibungen/Notizen

• 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.