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Main Authors: Mitrovic, Darko, Novak, Andrej
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2310.20383
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author Mitrovic, Darko
Novak, Andrej
author_facet Mitrovic, Darko
Novak, Andrej
contents Image inpainting involves filling in damaged or missing regions of an image by utilizing information from the surrounding areas. In this paper, we investigate a highly nonlinear partial differential equation inspired by the modified Cahn-Hilliard equation. Instead of using standard potentials that depend solely on pixel intensities, we consider morphological image enhancement filters that are based on a variant of the shock filter: : \begin{align*} \partial_t u &= Δ\left(-ν\arctan(Δu)|\nabla u| - μΔu \right)+ λ(u_0 - u). \end{align*} This is referred to as the Shock Filter Cahn-Hilliard Equation. This equation is nonlinear with respect to the second-order derivative, which poses significant mathematical challenges. To address these, we make use of a specific approximation argument, establishing the existence of a family of approximate solutions through the Leray-Schauder fixed point theorem and the Aubin-Lions lemma. In the limit, we obtain a solution strategy wherein we can prove the existence and uniqueness of solutions. Proving the latter involves the use of Young measures and Kruzhkov entropy type-admissibility conditions. Additionally, we use a numerical method based on the convexity splitting idea to approximate solutions of the nonlinear partial differential equation and achieve fast inpainting results. To demonstrate the effectiveness of our approach, we apply our method to standard binary images and compare it with variations of the Cahn-Hilliard equation commonly used in the field.
format Preprint
id arxiv_https___arxiv_org_abs_2310_20383
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Navigating the Complex Landscape of Shock Filter Cahn-Hilliard Equation: From Regularized to Entropy Solutions
Mitrovic, Darko
Novak, Andrej
Analysis of PDEs
65M06, 94A08, 68U10, 47H10, 35K55, 80A22
Image inpainting involves filling in damaged or missing regions of an image by utilizing information from the surrounding areas. In this paper, we investigate a highly nonlinear partial differential equation inspired by the modified Cahn-Hilliard equation. Instead of using standard potentials that depend solely on pixel intensities, we consider morphological image enhancement filters that are based on a variant of the shock filter: : \begin{align*} \partial_t u &= Δ\left(-ν\arctan(Δu)|\nabla u| - μΔu \right)+ λ(u_0 - u). \end{align*} This is referred to as the Shock Filter Cahn-Hilliard Equation. This equation is nonlinear with respect to the second-order derivative, which poses significant mathematical challenges. To address these, we make use of a specific approximation argument, establishing the existence of a family of approximate solutions through the Leray-Schauder fixed point theorem and the Aubin-Lions lemma. In the limit, we obtain a solution strategy wherein we can prove the existence and uniqueness of solutions. Proving the latter involves the use of Young measures and Kruzhkov entropy type-admissibility conditions. Additionally, we use a numerical method based on the convexity splitting idea to approximate solutions of the nonlinear partial differential equation and achieve fast inpainting results. To demonstrate the effectiveness of our approach, we apply our method to standard binary images and compare it with variations of the Cahn-Hilliard equation commonly used in the field.
title Navigating the Complex Landscape of Shock Filter Cahn-Hilliard Equation: From Regularized to Entropy Solutions
topic Analysis of PDEs
65M06, 94A08, 68U10, 47H10, 35K55, 80A22
url https://arxiv.org/abs/2310.20383