A data-dependent regularization method based on the graph Laplacian

Fuente: arXiv
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Autores principales: Bianchi, Davide, Evangelista, Davide, Aleotti, Stefano, Donatelli, Marco, Piccolomini, Elena Loli, Li, Wenbin
Formato: Preprint
Publicado: 2023
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author Bianchi, Davide
Evangelista, Davide
Aleotti, Stefano
Donatelli, Marco
Piccolomini, Elena Loli
Li, Wenbin
author_facet Bianchi, Davide
Evangelista, Davide
Aleotti, Stefano
Donatelli, Marco
Piccolomini, Elena Loli
Li, Wenbin
contents We investigate a variational method for ill-posed problems, named $\texttt{graphLa+}Ψ$, which embeds a graph Laplacian operator in the regularization term. The novelty of this method lies in constructing the graph Laplacian based on a preliminary approximation of the solution, which is obtained using any existing reconstruction method $Ψ$ from the literature. As a result, the regularization term is both dependent on and adaptive to the observed data and noise. We demonstrate that $\texttt{graphLa+}Ψ$ is a regularization method and rigorously establish both its convergence and stability properties. We present selected numerical experiments in 2D computerized tomography, wherein we integrate the $\texttt{graphLa+}Ψ$ method with various reconstruction techniques $Ψ$, including Filter Back Projection ($\texttt{graphLa+FBP}$), standard Tikhonov ($\texttt{graphLa+Tik}$), Total Variation ($\texttt{graphLa+TV}$), and a trained deep neural network ($\texttt{graphLa+Net}$). The $\texttt{graphLa+}Ψ$ approach significantly enhances the quality of the approximated solutions for each method $Ψ$. Notably, $\texttt{graphLa+Net}$ is outperforming, offering a robust and stable application of deep neural networks in solving inverse problems.
format Preprint
id arxiv_https___arxiv_org_abs_2312_16936
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A data-dependent regularization method based on the graph Laplacian
Bianchi, Davide
Evangelista, Davide
Aleotti, Stefano
Donatelli, Marco
Piccolomini, Elena Loli
Li, Wenbin
Numerical Analysis
47A52, 05C90, 68T07, 92C55
We investigate a variational method for ill-posed problems, named $\texttt{graphLa+}Ψ$, which embeds a graph Laplacian operator in the regularization term. The novelty of this method lies in constructing the graph Laplacian based on a preliminary approximation of the solution, which is obtained using any existing reconstruction method $Ψ$ from the literature. As a result, the regularization term is both dependent on and adaptive to the observed data and noise. We demonstrate that $\texttt{graphLa+}Ψ$ is a regularization method and rigorously establish both its convergence and stability properties. We present selected numerical experiments in 2D computerized tomography, wherein we integrate the $\texttt{graphLa+}Ψ$ method with various reconstruction techniques $Ψ$, including Filter Back Projection ($\texttt{graphLa+FBP}$), standard Tikhonov ($\texttt{graphLa+Tik}$), Total Variation ($\texttt{graphLa+TV}$), and a trained deep neural network ($\texttt{graphLa+Net}$). The $\texttt{graphLa+}Ψ$ approach significantly enhances the quality of the approximated solutions for each method $Ψ$. Notably, $\texttt{graphLa+Net}$ is outperforming, offering a robust and stable application of deep neural networks in solving inverse problems.
title A data-dependent regularization method based on the graph Laplacian
topic Numerical Analysis
47A52, 05C90, 68T07, 92C55
url https://arxiv.org/abs/2312.16936