An iterative thresholding algorithm for linear inverse problems with a sparsity constraint
We consider linear inverse problems where the solution is assumed to have a sparse expansion on an arbitrary preassigned orthonormal basis. We prove that replacing the usual quadratic regularizing penalties by weighted 𝓁p‐penalties on the coefficients of such expansions, with 1 ≤ p ≤ 2, still regula...
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| Published in: | Communications on pure and applied mathematics Vol. 57; no. 11; pp. 1413 - 1457 |
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| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Hoboken
Wiley Subscription Services, Inc., A Wiley Company
01.11.2004
Wiley John Wiley and Sons, Limited |
| Subjects: | |
| ISSN: | 0010-3640, 1097-0312 |
| Online Access: | Get full text |
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| Summary: | We consider linear inverse problems where the solution is assumed to have a sparse expansion on an arbitrary preassigned orthonormal basis. We prove that replacing the usual quadratic regularizing penalties by weighted 𝓁p‐penalties on the coefficients of such expansions, with 1 ≤ p ≤ 2, still regularizes the problem. Use of such 𝓁p‐penalized problems with p < 2 is often advocated when one expects the underlying ideal noiseless solution to have a sparse expansion with respect to the basis under consideration. To compute the corresponding regularized solutions, we analyze an iterative algorithm that amounts to a Landweber iteration with thresholding (or nonlinear shrinkage) applied at each iteration step. We prove that this algorithm converges in norm. © 2004 Wiley Periodicals, Inc. |
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| Bibliography: | ArticleID:CPA20042 NSF Grants - No. DMS-0070689; No. DMS-0219233 Action de Recherche Concertée - No. Nb 02/07-281 IAP-network in Statistics P5/24 ark:/67375/WNG-Z83KNMKD-7 FWO (Fund for Scientific Research - Flanders), Belgium - No. G.0174.03 AFOSR Grant - No. F49620-01-1-0099 istex:39034D4C676B5611F8DC991B07FD147B65460AD7 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 |
| ISSN: | 0010-3640 1097-0312 |
| DOI: | 10.1002/cpa.20042 |