Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach

This paper proposes a sparse regularization method with a novel sorted regularization function. Sparse regularization is commonly used to solve underdetermined inverse problems. Traditional sparse regularization functions, such as <inline-formula><tex-math notation="LaTeX">$L_{...

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Main Authors: Takayuki Sasaki, Kazuya Hayase, Masaki Kitahara, Shunsuke Ono
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Signal Processing
Subjects:
Online Access:https://ieeexplore.ieee.org/document/10840312/
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author Takayuki Sasaki
Kazuya Hayase
Masaki Kitahara
Shunsuke Ono
author_facet Takayuki Sasaki
Kazuya Hayase
Masaki Kitahara
Shunsuke Ono
author_sort Takayuki Sasaki
collection DOAJ
description This paper proposes a sparse regularization method with a novel sorted regularization function. Sparse regularization is commonly used to solve underdetermined inverse problems. Traditional sparse regularization functions, such as <inline-formula><tex-math notation="LaTeX">$L_{1}$</tex-math></inline-formula>-norm, suffer from problems like amplitude underestimation and vanishing perturbations. The reverse ordered weighted <inline-formula><tex-math notation="LaTeX">$L_{1}$</tex-math></inline-formula>-norm (ROWL) addresses these issues but introduces new challenges. These include developing an algorithm grounded in theory, not heuristics, reducing computational complexity, enabling the automatic determination of numerous parameters, and ensuring the number of iterations remains feasible. In this study, we propose a novel sparse regularization function called the reverse sorted sum of squares (RSSS) and then construct an unrolled algorithm that addresses both the aforementioned two problems and these four challenges. The core idea of our proposed method lies in transforming the optimization problem into a difference-of-convex programming problem, for which solutions are known. In experiments, we apply the RSSS regularization method to image deblurring and super-resolution tasks and confirmed its superior performance compared to conventional methods, all with feasible computational complexity.
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id doaj-art-68f9e0068ea843dab7879b66eaaccd1a
institution Kabale University
issn 2644-1322
language English
publishDate 2025-01-01
publisher IEEE
record_format Article
series IEEE Open Journal of Signal Processing
spelling doaj-art-68f9e0068ea843dab7879b66eaaccd1a2025-02-11T00:01:49ZengIEEEIEEE Open Journal of Signal Processing2644-13222025-01-016576710.1109/OJSP.2025.352931210840312Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex ApproachTakayuki Sasaki0https://orcid.org/0000-0002-0504-557XKazuya Hayase1https://orcid.org/0009-0000-0856-4239Masaki Kitahara2https://orcid.org/0009-0009-4260-1174Shunsuke Ono3https://orcid.org/0000-0001-7890-5131NTT Corporation, Yokosuka, JapanNTT Corporation, Yokosuka, JapanNTT Corporation, Yokosuka, JapanInstitute of Science Tokyo, Yokohama, JapanThis paper proposes a sparse regularization method with a novel sorted regularization function. Sparse regularization is commonly used to solve underdetermined inverse problems. Traditional sparse regularization functions, such as <inline-formula><tex-math notation="LaTeX">$L_{1}$</tex-math></inline-formula>-norm, suffer from problems like amplitude underestimation and vanishing perturbations. The reverse ordered weighted <inline-formula><tex-math notation="LaTeX">$L_{1}$</tex-math></inline-formula>-norm (ROWL) addresses these issues but introduces new challenges. These include developing an algorithm grounded in theory, not heuristics, reducing computational complexity, enabling the automatic determination of numerous parameters, and ensuring the number of iterations remains feasible. In this study, we propose a novel sparse regularization function called the reverse sorted sum of squares (RSSS) and then construct an unrolled algorithm that addresses both the aforementioned two problems and these four challenges. The core idea of our proposed method lies in transforming the optimization problem into a difference-of-convex programming problem, for which solutions are known. In experiments, we apply the RSSS regularization method to image deblurring and super-resolution tasks and confirmed its superior performance compared to conventional methods, all with feasible computational complexity.https://ieeexplore.ieee.org/document/10840312/Deep unrollingdifference-of-convexinverse problemnon-convex optimizationproximal splitting methodsparse regularization
spellingShingle Takayuki Sasaki
Kazuya Hayase
Masaki Kitahara
Shunsuke Ono
Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
IEEE Open Journal of Signal Processing
Deep unrolling
difference-of-convex
inverse problem
non-convex optimization
proximal splitting method
sparse regularization
title Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
title_full Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
title_fullStr Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
title_full_unstemmed Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
title_short Sparse Regularization With Reverse Sorted Sum of Squares via an Unrolled Difference-of-Convex Approach
title_sort sparse regularization with reverse sorted sum of squares via an unrolled difference of convex approach
topic Deep unrolling
difference-of-convex
inverse problem
non-convex optimization
proximal splitting method
sparse regularization
url https://ieeexplore.ieee.org/document/10840312/
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AT kazuyahayase sparseregularizationwithreversesortedsumofsquaresviaanunrolleddifferenceofconvexapproach
AT masakikitahara sparseregularizationwithreversesortedsumofsquaresviaanunrolleddifferenceofconvexapproach
AT shunsukeono sparseregularizationwithreversesortedsumofsquaresviaanunrolleddifferenceofconvexapproach