Variably Scaled Kernels for the regularized solution of the parametric Fourier imaging problem

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Main Authors: Volpara, Anna, Lupoli, Alessandro, Perracchione, Emma
Format: Preprint
Published: 2025
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author Volpara, Anna
Lupoli, Alessandro
Perracchione, Emma
author_facet Volpara, Anna
Lupoli, Alessandro
Perracchione, Emma
contents We address the problem of approximating parametric Fourier imaging problems via interpolation/ extrapolation algorithms that impose smoothing constraints across contiguous values of the parameter. Previous works already proved that interpolating via Variably Scaled Kernels (VSKs) the scattered observations in the Fourier domain and then defining the sought approximation via the projected Landweber iterative scheme, turns out to be effective. This study provides new theoretical insights, including error bounds in the image space and properties of the projected Landweber iterative scheme, both influenced by the choice of the scaling function, which characterizes the VSK basis. Such bounds then suggest a smarter solution for the definition of the scaling functions. Indeed, by means of VSKs, the information coded in an image reconstructed for a given parameter is transferred during the reconstruction process to a contiguous parameter value. Benchmark test cases in the field of astronomical imaging, numerically show that the proposed scheme is able to regularize along the parameter direction, thus proving reliable and interpretable results.
format Preprint
id arxiv_https___arxiv_org_abs_2505_14060
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Variably Scaled Kernels for the regularized solution of the parametric Fourier imaging problem
Volpara, Anna
Lupoli, Alessandro
Perracchione, Emma
Numerical Analysis
We address the problem of approximating parametric Fourier imaging problems via interpolation/ extrapolation algorithms that impose smoothing constraints across contiguous values of the parameter. Previous works already proved that interpolating via Variably Scaled Kernels (VSKs) the scattered observations in the Fourier domain and then defining the sought approximation via the projected Landweber iterative scheme, turns out to be effective. This study provides new theoretical insights, including error bounds in the image space and properties of the projected Landweber iterative scheme, both influenced by the choice of the scaling function, which characterizes the VSK basis. Such bounds then suggest a smarter solution for the definition of the scaling functions. Indeed, by means of VSKs, the information coded in an image reconstructed for a given parameter is transferred during the reconstruction process to a contiguous parameter value. Benchmark test cases in the field of astronomical imaging, numerically show that the proposed scheme is able to regularize along the parameter direction, thus proving reliable and interpretable results.
title Variably Scaled Kernels for the regularized solution of the parametric Fourier imaging problem
topic Numerical Analysis
url https://arxiv.org/abs/2505.14060