Linear Convergence of Plug-and-Play Algorithms with Kernel Denoisers

Fuente: arXiv
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Autori principali: Sinha, Arghya, Kumar, Bhartendu, Athalye, Chirayu D., Chaudhury, Kunal N.
Natura: Preprint
Pubblicazione: 2025
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author Sinha, Arghya
Kumar, Bhartendu
Athalye, Chirayu D.
Chaudhury, Kunal N.
author_facet Sinha, Arghya
Kumar, Bhartendu
Athalye, Chirayu D.
Chaudhury, Kunal N.
contents The use of denoisers for image reconstruction has shown significant potential, especially for the Plug-and-Play (PnP) framework. In PnP, a powerful denoiser is used as an implicit regularizer in proximal algorithms such as ISTA and ADMM. The focus of this work is on the convergence of PnP iterates for linear inverse problems using kernel denoisers. It was shown in prior work that the update operator in standard PnP is contractive for symmetric kernel denoisers under appropriate conditions on the denoiser and the linear forward operator. Consequently, we could establish global linear convergence of the iterates using the contraction mapping theorem. In this work, we develop a unified framework to establish global linear convergence for symmetric and nonsymmetric kernel denoisers. Additionally, we derive quantitative bounds on the contraction factor (convergence rate) for inpainting, deblurring, and superresolution. We present numerical results to validate our theoretical findings.
format Preprint
id arxiv_https___arxiv_org_abs_2505_15318
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear Convergence of Plug-and-Play Algorithms with Kernel Denoisers
Sinha, Arghya
Kumar, Bhartendu
Athalye, Chirayu D.
Chaudhury, Kunal N.
Image and Video Processing
Optimization and Control
94A08, 41A25, 65F10
The use of denoisers for image reconstruction has shown significant potential, especially for the Plug-and-Play (PnP) framework. In PnP, a powerful denoiser is used as an implicit regularizer in proximal algorithms such as ISTA and ADMM. The focus of this work is on the convergence of PnP iterates for linear inverse problems using kernel denoisers. It was shown in prior work that the update operator in standard PnP is contractive for symmetric kernel denoisers under appropriate conditions on the denoiser and the linear forward operator. Consequently, we could establish global linear convergence of the iterates using the contraction mapping theorem. In this work, we develop a unified framework to establish global linear convergence for symmetric and nonsymmetric kernel denoisers. Additionally, we derive quantitative bounds on the contraction factor (convergence rate) for inpainting, deblurring, and superresolution. We present numerical results to validate our theoretical findings.
title Linear Convergence of Plug-and-Play Algorithms with Kernel Denoisers
topic Image and Video Processing
Optimization and Control
94A08, 41A25, 65F10
url https://arxiv.org/abs/2505.15318