Reconstruction of Piecewise Smooth Functions Based on Fourier Extension

This paper proposes a hierarchical Fourier extension framework for the accurate reconstruction of piecewise smooth functions with mixed-order singularities. To address key challenges in spectral approximation–namely boundary-induced artifacts, instability in edge detection, and loss of accuracy near...

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Bibliographic Details
Main Authors: Xusheng Li, Zhenyu Zhao, Xianzheng Jia
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Axioms
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Online Access:https://www.mdpi.com/2075-1680/14/7/489
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Summary:This paper proposes a hierarchical Fourier extension framework for the accurate reconstruction of piecewise smooth functions with mixed-order singularities. To address key challenges in spectral approximation–namely boundary-induced artifacts, instability in edge detection, and loss of accuracy near discontinuities–the method integrates three main components: (1) boundary-focused Fourier extensions that isolate endpoint effects while preserving internal structures; (2) a multi-stage edge detection strategy combining spectral mollifiers and coordinate transformations to identify discontinuities in function values and their derivatives; (3) adaptive domain partitioning followed by localized Fourier extensions to retain spectral accuracy on smooth segments. Numerical results demonstrate near machine-precision accuracy (∼10<sup>−14</sup>–10<sup>−15</sup>) with significantly improved stability and performance over traditional global methods.
ISSN:2075-1680