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Autori principali: Beinert, Robert, Bresch, Jonas
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2404.13181
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author Beinert, Robert
Bresch, Jonas
author_facet Beinert, Robert
Bresch, Jonas
contents Circle- and sphere-valued data play a significant role in inverse problems like magnetic resonance phase imaging and radar interferometry, in the analysis of directional information, and in color restoration tasks. In this paper, we aim to restore $(d-1)$-sphere-valued signals exploiting the classical anisotropic total variation on the surrounding $d$-dimensional Euclidean space. For this, we propose a novel variational formulation, whose data fidelity is based on inner products instead of the usually employed squared norms. Convexifying the resulting non-convex problem and using ADMM, we derive an efficient and fast numerical denoiser. In the special case of binary (0-sphere-valued) signals, the relaxation is provable tight, i.e. the relaxed solution can be used to construct a solution of the original non-convex problem. Moreover, the tightness can be numerically observed for barcode and QR code denoising as well as in higher dimensional experiments like the color restoration using hue and chromaticity and the recovery of SO(3)-valued signals.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13181
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Denoising Sphere-Valued Data by Relaxed Total Variation Regularization
Beinert, Robert
Bresch, Jonas
Numerical Analysis
Optimization and Control
94A08, 94A12, 65J22, 90C22, 90C25
Circle- and sphere-valued data play a significant role in inverse problems like magnetic resonance phase imaging and radar interferometry, in the analysis of directional information, and in color restoration tasks. In this paper, we aim to restore $(d-1)$-sphere-valued signals exploiting the classical anisotropic total variation on the surrounding $d$-dimensional Euclidean space. For this, we propose a novel variational formulation, whose data fidelity is based on inner products instead of the usually employed squared norms. Convexifying the resulting non-convex problem and using ADMM, we derive an efficient and fast numerical denoiser. In the special case of binary (0-sphere-valued) signals, the relaxation is provable tight, i.e. the relaxed solution can be used to construct a solution of the original non-convex problem. Moreover, the tightness can be numerically observed for barcode and QR code denoising as well as in higher dimensional experiments like the color restoration using hue and chromaticity and the recovery of SO(3)-valued signals.
title Denoising Sphere-Valued Data by Relaxed Total Variation Regularization
topic Numerical Analysis
Optimization and Control
94A08, 94A12, 65J22, 90C22, 90C25
url https://arxiv.org/abs/2404.13181