Computing reconstructions from nonuniform Fourier samples: Universality of stability barriers and stable sampling rates |
| |
Authors: | Ben Adcock Milana Gataric José Luis Romero |
| |
Institution: | 1. Department of Mathematics, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada;2. DPMMS, Faculty of Mathematics, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WB, UK;3. Acoustics Research Institute, Austrian Academy of Sciences, Wohllebengasse 12–14, Vienna, 1040, Austria |
| |
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. |
| |
Keywords: | Nonuniform sampling Generalized sampling Stable recovery Fourier frame bounds Voronoi weights |
本文献已被 ScienceDirect 等数据库收录! |
|