1. Computing reconstructions from nonuniform Fourier samples: Universality of stability barriers and stable sampling rates
- Author
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José Luis Romero, Ben Adcock, Milana Gataric, Gataric, Milana [0000-0003-3915-2266], and Apollo - University of Cambridge Repository
- Subjects
94A20, 94A12, 94A08, 42B05, 42C15, 65T40 ,Nonuniform sampling ,010103 numerical & computational mathematics ,Radial line ,Stable recovery ,Generalized sampling ,01 natural sciences ,Regular grid ,symbols.namesake ,Wavelet ,FOS: Mathematics ,Applied mathematics ,Mathematics - Numerical Analysis ,0101 mathematics ,Mathematics ,Applied Mathematics ,010102 general mathematics ,Numerical Analysis (math.NA) ,Universality (dynamical systems) ,Fourier transform ,Rate of convergence ,symbols ,Fourier frame bounds ,Voronoi weights ,Numerical stability - Abstract
We study the problem of recovering an unknown compactly-supported multivariate function from samples of its Fourier transform that are acquired nonuniformly, i.e. not necessarily on a uniform Cartesian grid. Reconstruction problems of this kind arise in various imaging applications, where Fourier samples are taken along radial lines or spirals for example. Specifically, we consider finite-dimensional reconstructions, where a limited number of samples is available, and investigate the rate of convergence of such approximate solutions and their numerical stability. We show that the proportion of Fourier samples that allow for stable approximations of a given numerical accuracy is independent of the specific sampling geometry and is therefore universal for different sampling scenarios. This allows us to relate both sufficient and necessary conditions for different sampling setups and to exploit several results that were previously available only for very specific sampling geometries. The results are obtained by developing: (i) a transference argument for different measures of the concentration of the Fourier transform and Fourier samples; (ii) frame bounds valid up to the critical sampling density, which depend explicitly on the sampling set and the spectrum. As an application, we identify sufficient and necessary conditions for stable and accurate reconstruction of algebraic polynomials or wavelet coefficients from nonuniform Fourier data., 24 pages
- Published
- 2018
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