Feasibility-based fixed point networks

Abstract Inverse problems consist of recovering a signal from a collection of noisy measurements. These problems can often be cast as feasibility problems; however, additional regularization is typically necessary to ensure accurate and stable recovery with respect to data perturbations. Hand-chosen...

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Autores principales: Howard Heaton, Samy Wu Fung, Aviv Gibali, Wotao Yin
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Lenguaje:EN
Publicado: SpringerOpen 2021
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Acceso en línea:https://doaj.org/article/44f7425af370421a908ad4da0f3a81fc
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spelling oai:doaj.org-article:44f7425af370421a908ad4da0f3a81fc2021-11-28T12:14:03ZFeasibility-based fixed point networks10.1186/s13663-021-00706-32730-5422https://doaj.org/article/44f7425af370421a908ad4da0f3a81fc2021-11-01T00:00:00Zhttps://doi.org/10.1186/s13663-021-00706-3https://doaj.org/toc/2730-5422Abstract Inverse problems consist of recovering a signal from a collection of noisy measurements. These problems can often be cast as feasibility problems; however, additional regularization is typically necessary to ensure accurate and stable recovery with respect to data perturbations. Hand-chosen analytic regularization can yield desirable theoretical guarantees, but such approaches have limited effectiveness recovering signals due to their inability to leverage large amounts of available data. To this end, this work fuses data-driven regularization and convex feasibility in a theoretically sound manner. This is accomplished using feasibility-based fixed point networks (F-FPNs). Each F-FPN defines a collection of nonexpansive operators, each of which is the composition of a projection-based operator and a data-driven regularization operator. Fixed point iteration is used to compute fixed points of these operators, and weights of the operators are tuned so that the fixed points closely represent available data. Numerical examples demonstrate performance increases by F-FPNs when compared to standard TV-based recovery methods for CT reconstruction and a comparable neural network based on algorithm unrolling. Codes are available on Github: github.com/howardheaton/feasibility_fixed_point_networks .Howard HeatonSamy Wu FungAviv GibaliWotao YinSpringerOpenarticleConvex feasibility problemProjectionAveragedFixed point networkNonexpansiveLearned regularizerApplied mathematics. Quantitative methodsT57-57.97AnalysisQA299.6-433ENFixed Point Theory and Algorithms for Sciences and Engineering, Vol 2021, Iss 1, Pp 1-19 (2021)
institution DOAJ
collection DOAJ
language EN
topic Convex feasibility problem
Projection
Averaged
Fixed point network
Nonexpansive
Learned regularizer
Applied mathematics. Quantitative methods
T57-57.97
Analysis
QA299.6-433
spellingShingle Convex feasibility problem
Projection
Averaged
Fixed point network
Nonexpansive
Learned regularizer
Applied mathematics. Quantitative methods
T57-57.97
Analysis
QA299.6-433
Howard Heaton
Samy Wu Fung
Aviv Gibali
Wotao Yin
Feasibility-based fixed point networks
description Abstract Inverse problems consist of recovering a signal from a collection of noisy measurements. These problems can often be cast as feasibility problems; however, additional regularization is typically necessary to ensure accurate and stable recovery with respect to data perturbations. Hand-chosen analytic regularization can yield desirable theoretical guarantees, but such approaches have limited effectiveness recovering signals due to their inability to leverage large amounts of available data. To this end, this work fuses data-driven regularization and convex feasibility in a theoretically sound manner. This is accomplished using feasibility-based fixed point networks (F-FPNs). Each F-FPN defines a collection of nonexpansive operators, each of which is the composition of a projection-based operator and a data-driven regularization operator. Fixed point iteration is used to compute fixed points of these operators, and weights of the operators are tuned so that the fixed points closely represent available data. Numerical examples demonstrate performance increases by F-FPNs when compared to standard TV-based recovery methods for CT reconstruction and a comparable neural network based on algorithm unrolling. Codes are available on Github: github.com/howardheaton/feasibility_fixed_point_networks .
format article
author Howard Heaton
Samy Wu Fung
Aviv Gibali
Wotao Yin
author_facet Howard Heaton
Samy Wu Fung
Aviv Gibali
Wotao Yin
author_sort Howard Heaton
title Feasibility-based fixed point networks
title_short Feasibility-based fixed point networks
title_full Feasibility-based fixed point networks
title_fullStr Feasibility-based fixed point networks
title_full_unstemmed Feasibility-based fixed point networks
title_sort feasibility-based fixed point networks
publisher SpringerOpen
publishDate 2021
url https://doaj.org/article/44f7425af370421a908ad4da0f3a81fc
work_keys_str_mv AT howardheaton feasibilitybasedfixedpointnetworks
AT samywufung feasibilitybasedfixedpointnetworks
AT avivgibali feasibilitybasedfixedpointnetworks
AT wotaoyin feasibilitybasedfixedpointnetworks
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