Monotonicity of the jump set and jump amplitudes in one-dimensional TV denoising

Fuente: arXiv
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Autori principali: Cristoferi, Riccardo, Ferreira, Rita, Fonseca, Irene, Iglesias, José A.
Natura: Preprint
Pubblicazione: 2025
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author Cristoferi, Riccardo
Ferreira, Rita
Fonseca, Irene
Iglesias, José A.
author_facet Cristoferi, Riccardo
Ferreira, Rita
Fonseca, Irene
Iglesias, José A.
contents We revisit the classical problem of denoising a one-dimensional scalar-valued function by minimizing the sum of an $L^2$ fidelity term and the total variation, scaled by a regularization parameter. This study focuses on proving that the jump set of solutions, corresponding to discontinuities or edges, as well as the amplitude of the jumps are nonincreasing as the regularization parameter increases. Compared with previous works, our results apply to a strictly larger class of input functions, extending beyond the traditional setting of functions of bounded variation to any input in $L^\infty$ with left and right approximate limits everywhere. The proof leverages competitor constructions and convexity properties of the taut string problem, a well-known equivalent formulation of the TV model. This monotonicity property reflects that the extent to which geometric and topological features of the original signal are preserved is consistent with the amount of smoothing desired when formulating the denoising method.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11714
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Monotonicity of the jump set and jump amplitudes in one-dimensional TV denoising
Cristoferi, Riccardo
Ferreira, Rita
Fonseca, Irene
Iglesias, José A.
Optimization and Control
26A45, 26A46, 94A12, 68U10
We revisit the classical problem of denoising a one-dimensional scalar-valued function by minimizing the sum of an $L^2$ fidelity term and the total variation, scaled by a regularization parameter. This study focuses on proving that the jump set of solutions, corresponding to discontinuities or edges, as well as the amplitude of the jumps are nonincreasing as the regularization parameter increases. Compared with previous works, our results apply to a strictly larger class of input functions, extending beyond the traditional setting of functions of bounded variation to any input in $L^\infty$ with left and right approximate limits everywhere. The proof leverages competitor constructions and convexity properties of the taut string problem, a well-known equivalent formulation of the TV model. This monotonicity property reflects that the extent to which geometric and topological features of the original signal are preserved is consistent with the amount of smoothing desired when formulating the denoising method.
title Monotonicity of the jump set and jump amplitudes in one-dimensional TV denoising
topic Optimization and Control
26A45, 26A46, 94A12, 68U10
url https://arxiv.org/abs/2502.11714