| A new twIst: two-step iterative shrinkage/thresholding algorithms for image restoration. | |
| | |
MedLine Citation:
|
PMID: 18092598 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Iterative shrinkage/thresholding (IST) algorithms have been recently proposed to handle a class of convex unconstrained optimization problems arising in image restoration and other linear inverse problems. This class of problems results from combining a linear observation model with a nonquadratic regularizer (e.g., total variation or wavelet-based regularization). It happens that the convergence rate of these IST algorithms depends heavily on the linear observation operator, becoming very slow when this operator is ill-conditioned or ill-posed. In this paper, we introduce two-step IST (TwIST) algorithms, exhibiting much faster convergence rate than IST for ill-conditioned problems. For a vast class of nonquadratic convex regularizers (l(p) norms, some Besov norms, and total variation), we show that TwIST converges to a minimizer of the objective function, for a given range of values of its parameters. For noninvertible observation operators, we introduce a monotonic version of TwIST (MTwIST); although the convergence proof does not apply to this scenario, we give experimental evidence that MTwIST exhibits similar speed gains over IST. The effectiveness of the new methods are experimentally confirmed on problems of image deconvolution and of restoration with missing samples. |
| | |
Authors:
|
José M Bioucas-Dias; Mario A T Figueiredo |
Related Documents
:
|
11308468 - Irreversible and reversible modes of operation of deterministic ratchets. 18606028 - The transmission and control of xdr tb in south africa: an operations research and math... 620018 - Proton electrochemical gradient and phosphate potential in mitochondria. 1933118 - Free second toe transfer for reconstruction of the distal phalanx of the fingers. 15676978 - Evaluation of the seating of qantas flight deck crew. 22462228 - Thoughts on intervention in hiv/aids with traditional chinese medicine. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: IEEE transactions on image processing : a publication of the IEEE Signal Processing Society Volume: 16 ISSN: 1057-7149 ISO Abbreviation: IEEE Trans Image Process Publication Date: 2007 Dec |
Date Detail:
|
Created Date: 2007-12-20 Completed Date: 2008-01-15 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 9886191 Medline TA: IEEE Trans Image Process Country: United States |
Other Details:
|
Languages: eng Pagination: 2992-3004 Citation Subset: IM |
Affiliation:
|
Instituto de Telecomunicações and the Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisboa, Portugal. jose.bioucas@lx.it.pt |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Algorithms* Image Enhancement / methods* Image Interpretation, Computer-Assisted / methods* Pattern Recognition, Automated / methods* Reproducibility of Results Sensitivity and Specificity Signal Processing, Computer-Assisted* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Majorization-minimization algorithms for wavelet-based image restoration.
Next Document: Blind deconvolution of medical ultrasound images: a parametric inverse filtering approach.