scholarly journals Unitary Extension Principle for Nonuniform Wavelet Frames in L2(ℝ)

2021 ◽  
Vol 17 (1) ◽  
pp. 79-94
Author(s):  
Hari Krishan Malhotra ◽  
◽  
Lalit Kumar Vashisht ◽  
Keyword(s):  
Extension Principle ◽  
Wavelet Frames ◽  
Unitary Extension

On Parseval Wavelet Frames with Two or Three Generators via the Unitary Extension Principle

2014 ◽  
Vol 57 (2) ◽  
pp. 254-263 ◽  
Author(s):  
Ole Christensen ◽  
Hong Oh Kim ◽  
Rae Young Kim
Keyword(s):  
Extension Principle ◽  
Sufficient Condition ◽  
Wavelet Frame ◽  
Wavelet Frames ◽  
Wavelet System ◽  
Number Of Generators ◽  
Unitary Extension

AbstractThe unitary extension principle (UEP) by A. Ron and Z. Shen yields a sufficient condition for the construction of Parseval wavelet frames with multiple generators. In this paper we characterize the UEP-type wavelet systems that can be extended to a Parseval wavelet frame by adding just one UEP-type wavelet system. We derive a condition that is necessary for the extension of a UEP-type wavelet system to any Parseval wavelet frame with any number of generators and prove that this condition is also sufficient to ensure that an extension with just two generators is possible.

The Study of Tight Periodic Wavelet Frames and Wavelet Frame Packets and Applications

2014 ◽  
Vol 977 ◽  
pp. 532-535
Author(s):  
Qing Jiang Chen ◽  
Yu Zhou Chai ◽  
Chuan Li Cai
Keyword(s):  
Information Science ◽  
Approximation Order ◽  
Tight Frame ◽  
Extension Principle ◽  
Wavelet Frames ◽  
Decomposition Scheme ◽  
Periodic Wavelet ◽  
Unitary Extension ◽  
Periodic Wavelet Frames ◽  
Necessary And Sufficient

Information science focuses on understanding problems from the perspective of the stake holders involved and then applying information and other technologies as needed. A necessary and sufficient condition is identified in term of refinement masks for applying the unitary extension principle for periodic functions to construct tight wavelet frames. Then a theory on the approxi-mation order of truncated tight frame series is established, which facilitates construction of tight periodic wavelet frames with desirable approximation order. The pyramid decomposition scheme is derived based on the generalized multiresolution structure.

scholarly journals Polyphase matrix characterization of framelets on local fields of positive characteristic

2017 ◽  
Vol 9 (1) ◽  
pp. 248-259
Author(s):  
F. A. Shah ◽  
M. Y. Bhat
Keyword(s):  
Positive Characteristic ◽  
Local Fields ◽  
Extension Principle ◽  
Wavelet Frames ◽  
Unitary Extension ◽  
Polyphase Matrix

AbstractAn important tool for the construction of framelets on local fields of positive characteristic using unitary extension principle was presented by Shah and Debnath [Tight wavelet frames on local fields, Analysis, 33 (2013), 293-307]. In this article, we continue the study of framelets on local fields and present a polyphase matrix characterization of framelets generated by the extension principle.

CONSTRUCTION OF SYMMETRIC TIGHT WAVELET FRAMES FROM QUASI-INTERPOLATORY SUBDIVISION MASKS AND THEIR APPLICATIONS

2008 ◽  
Vol 06 (01) ◽  
pp. 97-120 ◽  
Author(s):  
BYEONGSEON JEONG ◽  
MYUNGJIN CHOI ◽  
HONG OH KIM
Keyword(s):  
Filter Bank ◽  
Extension Principle ◽  
Discrete Wavelet ◽  
Wavelet Frame ◽  
Wavelet Frames ◽  
Vanishing Moments ◽  
Frequency Scale ◽  
Unitary Extension ◽  
Signal Image ◽  
Interpolatory Subdivision

This paper presents tight wavelet frames with two compactly supported symmetric generators of more than one vanishing moments in the Unitary Extension Principle. We determine all possible free tension parameters of the quasi-interpolatory subdivision masks whose corresponding refinable functions guarantee our wavelet frame. In order to reduce shift variance of the standard discrete wavelet transform, we use the three times oversampling filter bank and eventually obtain a ternary (low, middle, high) frequency scale. In applications to signal/image denoising and erasure recovery, the results demonstrate reduced shift variance and better performance of our wavelet frame than the usual wavelet systems such as Daubechies wavelets.

A PAIR OF ORTHOGONAL WAVELET FRAMES IN L2(ℝd)

2014 ◽  
Vol 12 (02) ◽  
pp. 1450011 ◽  
Author(s):  
GHANSHYAM BHATT
Keyword(s):  
Dimensional Case ◽  
Extension Principle ◽  
Higher Dimension ◽  
Wavelet Frames ◽  
Orthogonal Wavelet ◽  
Extra Condition ◽  
Simple Method ◽  
One Dimensional ◽  
Unitary Extension ◽  
Polyphase Matrix

A simple method of construction of a pair of orthogonal wavelet frames in L2(ℝd) is presented. This is a generalization of one-dimensional case to higher dimension. The construction is based on the well-known Unitary Extension Principle (UEP). The presented method produces the polyphase components of the filters of the wavelet functions, and hence the filters. A pair of orthogonal wavelet frames can be constructed with an extra condition. In the construction, the polyphase matrix is used as opposed to the modulation matrix. This is less restrictive and yields a fewer wavelet functions in the system than in the previously known constructions.

scholarly journals Construction of nonuniform periodic wavelet frames on non-Archimedean fields

2020 ◽  
Vol 74 (2) ◽  
pp. 1
Author(s):  
Owais Ahmad
Keyword(s):  
Real Life ◽  
Discrete Subgroup ◽  
Extension Principle ◽  
Mathematical Tool ◽  
Wavelet Frames ◽  
Spectral Pair ◽  
Periodic Wavelet ◽  
Spectral Pairs ◽  
Unitary Extension ◽  
Periodic Wavelet Frames

In real life applications not all signals are obtained by uniform shifts; so there is a natural question regarding analysis and decompositions of these types of signals by a stable mathematical tool. Gabardo and Nashed, and Gabardo and Yu filled this gap by the concept of nonuniform multiresolution analysis and nonuniform wavelets based on the theory of spectral pairs for which the associated translation set \(\Lambda= \{0,r/N\}+2\mathbb{Z}\) is no longer a discrete subgroup of \(\mathbb{R}\) but a spectrum associated with a certain one-dimensional spectral pair and the associated dilation is an even positive integer related to the given spectral pair. In this paper, we introduce a notion of nonuniform periodic wavelet frame on non-Archimedean field. Using the Fourier transform technique and the unitary extension principle, we propose an approach for the construction of nonuniform periodic wavelet frames on non-Archimedean fields.

TIGHT FRAME CHARACTERIZATION OF MULTIWAVELET VECTOR FUNCTIONS IN TERMS OF THE POLYPHASE MATRIX

2009 ◽  
Vol 07 (01) ◽  
pp. 9-21 ◽  
Author(s):  
JENS KROMMWEH
Keyword(s):  
Tight Frame ◽  
Extension Principle ◽  
Wavelet Frames ◽  
Unitary Extension ◽  
Directional Wavelets ◽  
Extension Principles ◽  
Polyphase Matrix ◽  
Common Extension ◽  
Polyphase Representation

The extension principles play an important role in characterizing and constructing of wavelet frames. The common extension principles, the unitary extension principle (UEP) or the oblique extension principle (OEP), are based on the unitarity of the modulation matrix. In this paper, we state the UEP and OEP for refinable function vectors in the polyphase representation. Finally, we apply our results to directional wavelets on triangles which we have constructed in a previous work. We will show that the wavelet system generates a tight frame for L2(ℝ2).

scholarly journals Some Bivariate Smooth Compactly Supported Tight Framelets with Three Generators

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
A. San Antolín ◽  
R. A. Zalik
Keyword(s):  
Closed Form ◽  
Spectral Factorization ◽  
Extension Principle ◽  
Refinable Functions ◽  
Wavelet Frames ◽  
Compactly Supported ◽  
Slight Generalization ◽  
Dilation Matrix ◽  
Transcendental Functions ◽  
Low Degrees

For any dilation matrix with integer entries and , we construct a family of smooth compactly supported tight wavelet frames with three generators in . Our construction involves some compactly supported refinable functions, the oblique extension principle, and a slight generalization of a theorem of Lai and Stöckler. Estimates for the degrees of smoothness are given. With the exception of a polynomial whose coefficients must in general be computed by spectral factorization, the framelets are expressed in closed form in the frequency domain, in terms of elementary transcendental functions. By means of two examples we also show that for low degrees of smoothness the use of spectral factorization may be avoided.

GMRA-BASED CONSTRUCTION OF FRAMELETS IN REDUCING SUBSPACES OF L2(ℝd)

2011 ◽  
Vol 09 (02) ◽  
pp. 237-268 ◽  
Author(s):  
YUN-ZHANG LI ◽  
FENG-YING ZHOU
Keyword(s):  
Explicit Construction ◽  
Extension Principle ◽  
Reducing Subspaces ◽  
Unitary Extension ◽  
Expansive Matrix

This paper develops GMRA-based construction procedures of Parseval framelets in the setting of reducing subspaces of L2(ℝd). A unitary extension principle is established; in particular, for a general expansive matrix A with | det A| = 2, an explicit construction of Parseval framelets is obtained. Some examples are also provided to illustrate the generality of our theory.

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