نتایج جستجو برای: tight frames
تعداد نتایج: 98383 فیلتر نتایج به سال:
In this paper we study the fusion frame potential, that is a generalization of the BenedettoFickus (vectorial) frame potential to the finite-dimensional fusion frame setting. Local and global minimizers of this potential are studied, when we restrict it to a suitable set of fusion frames. These minimizers are related to tight fusion frames as in the classical vector frame case. Still, tight fus...
Fusion frame theory is an emerging mathematical theory that provides a natural framework for performing hierarchical data processing. In this paper, we introduce the notion of a sparse fusion frame, that is, a fusion frame whose subspaces are generated by orthonormal basis vectors that are sparse in a ‘uniform basis’ over all subspaces, thereby enabling low-complexity fusion frame decomposition...
Frames have been used to capture significant signal characteristics, provide numerical stability of reconstruction, and enhance resilience to additive noise. This paper places frames in a new setting, where some of the elements are deleted. Since proper subsets of frames are sometimes themselves frames, a quantized frame expansion can be a useful representation even when some transform coeffici...
An equiangular tight frame (ETF) is a d × N matrix that has unit-norm columns and orthogonal rows of norm √ N/d. Its key property is that the absolute inner products between pairs of columns are (i) identical and (ii) as small as possible. ETFs have applications in communications, coding theory, and sparse approximation. Numerical experiments indicate that ETFs arise for very few pairs (d,N), a...
In this article, we show that a finite dimensional Hilbert space can have an infinite Bessel sequence, but a normalized Bessel sequence in a finite dimensional Hilbert space must be of finite length. A relation between the dimension of a given finite dimensional Hilbert space and the bound of any finite normalized tight frame for the underlying space is obtained. Also some properties of the fra...
This paper considers the design of wavelet tight frames based on iterated oversampled lter banks. The greater design freedom available makes possible the construction of wavelets with a high degree of smoothness, in comparison with orthonormal wavelet bases. Grr obner bases are used to obtain the solutions to the nonlinear design equations. Following the dual-tree DWT of Kingsbury, one goal is ...
Frames have become standard tools in signal processing due to their robustness to transmission errors and their resilience to noise. Equiangular tight frames (ETFs) are particularly useful and have been shown to be optimal for transmission under a certain number of erasures. Unfortunately, ETFs do not exist in many cases and are hard to construct when they do exist. However, it is known that an...
Two simple constructive methods are presented to compute compactly supported tight wavelet frames for any given refinable function whose mask satisfies the QMF or sub-QMF conditions in the multivariate setting. We use one of our constructive methods in order to find tight wavelet frames associated with multivariate box splines, e.g., bivariate box splines on a three or four directional mesh. Mo...
| We study frames for robust transmission over the Internet. In our previous work, we used quantized nite-dimensional frames to achieve resilience to packet losses; here, we allow the input to be a sequence in`2 (Z) and focus on a lter-bank implementation of the system. We present results in parallel, R N or C N versus`2 (Z), and show that uniform tight frames, as well as newly introduced stron...
From the definition of tight frames, normalized with frame bound constant equal to one, a tight frame of wavelets can be considered as a natural generalization of an orthonormal wavelet basis, with the only exception that the wavelets are not required to have norm equal to one. However, without the orthogonality property, the tight-frame wavelets do not necessarily have vanishing moments of ord...
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