Characterization and computation of canonical tight windows for Gabor frames

Fuente: arXiv
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Main Authors: Janssen, A. J. E. M, Strohmer, Thomas
Format: Preprint
Published: 2000
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author Janssen, A. J. E. M
Strohmer, Thomas
author_facet Janssen, A. J. E. M
Strohmer, Thomas
contents Let $(g_{nm})_{n,m\in Z}$ be a Gabor frame for $L_2(R)$ for given window $g$. We show that the window $h^0=S^{-1/2} g$ that generates the canonically associated tight Gabor frame minimizes $\|g-h\|$ among all windows $h$ generating a normalized tight Gabor frame. We present and prove versions of this result in the time domain, the frequency domain, the time-frequency domain, and the Zak transform domain, where in each domain the canonical $h^0$ is expressed using functional calculus for Gabor frame operators. Furthermore, we derive a Wiener-Levy type theorem for rationally oversampled Gabor frames. Finally, a Newton-type method for a fast numerical calculation of $\ho$ is presented. We analyze the convergence behavior of this method and demonstrate the efficiency of the proposed algorithm by some numerical examples.
format Preprint
id arxiv_https___arxiv_org_abs_math_0010245
institution arXiv
publishDate 2000
record_format arxiv
spellingShingle Characterization and computation of canonical tight windows for Gabor frames
Janssen, A. J. E. M
Strohmer, Thomas
Functional Analysis
Numerical Analysis
42C15, 47A60, 94A11, 94A12
Let $(g_{nm})_{n,m\in Z}$ be a Gabor frame for $L_2(R)$ for given window $g$. We show that the window $h^0=S^{-1/2} g$ that generates the canonically associated tight Gabor frame minimizes $\|g-h\|$ among all windows $h$ generating a normalized tight Gabor frame. We present and prove versions of this result in the time domain, the frequency domain, the time-frequency domain, and the Zak transform domain, where in each domain the canonical $h^0$ is expressed using functional calculus for Gabor frame operators. Furthermore, we derive a Wiener-Levy type theorem for rationally oversampled Gabor frames. Finally, a Newton-type method for a fast numerical calculation of $\ho$ is presented. We analyze the convergence behavior of this method and demonstrate the efficiency of the proposed algorithm by some numerical examples.
title Characterization and computation of canonical tight windows for Gabor frames
topic Functional Analysis
Numerical Analysis
42C15, 47A60, 94A11, 94A12
url https://arxiv.org/abs/math/0010245