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1.
Compactly supported (bi)orthogonal wavelets generated by interpolatory refinable functions 总被引:7,自引:0,他引:7
This paper provides several constructions of compactly supported wavelets generated by interpolatory refinable functions.
It was shown in [7] that there is no real compactly supported orthonormal symmetric dyadic refinable function, except the
trivial case; and also shown in [10,18] that there is no compactly supported interpolatory orthonormal dyadic refinable function.
Hence, for the dyadic dilation case, compactly supported wavelets generated by interpolatory refinable functions have to be
biorthogonal wavelets. The key step to construct the biorthogonal wavelets is to construct a compactly supported dual function
for a given interpolatory refinable function. We provide two explicit iterative constructions of such dual functions with
desired regularity. When the dilation factors are larger than 3, we provide several examples of compactly supported interpolatory
orthonormal symmetric refinable functions from a general method. This leads to several examples of orthogonal symmetric (anti‐symmetric)
wavelets generated by interpolatory refinable functions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
2.
It is well known that in the univariate case, up to an integer shift and possible sign change, there is no dyadic compactly
supported symmetric orthonormal scaling function except for the Haar function. In this paper we are concerned with the construction
of symmetric orthonormal scaling functions with dilation factor d=4. Several examples of such orthonormal scaling functions are provided in this paper. In particular, two examples of C
1 orthonormal scaling functions, which are symmetric about 0 and 1/6, respectively, are presented. We will then discuss how
to construct symmetric wavelets from these scaling functions. We explicitly construct the corresponding orthonormal symmetric
wavelets for all the examples given in this paper.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
基于仿酉矩阵的对称扩充方法,该文提出了一种尺度因子为3的紧支撑高维正交对称小波构造算法.即设φ(x)∈L~2(R~d)是尺度因子为3的紧支撑d维正交对称尺度函数,P(ξ)是它的两尺度符号,p_(0,v)(ξ)为P(ξ)的相位符号.首先提出一种向量的对称正交变换,应用对称正交变换对3~d维向量(p_(0,v)(ξ))_v,v∈E_d的分量进行对称化.通过仿酉矩阵的对称扩充,给出了3~d-1个紧支撑高维正交对称小波构造.这种方法构造的小波支撑不超过尺度函数的支撑.最后给出一个构造算例. 相似文献
4.
§ 1. Introduction SinceDAUBECHIES [1 ]gavethewellknownconstructionofunivariatecompactlysup portedorthonormalwavelets,considerableattertionhasbeenspentonconstructingmultivariatecompactlysupportedorthonormalwavelets [2— 5etc.] .Althoughmanyspecialbivariatenon separablewaveletshavebeenconstructed ,itisstillanopenproblemhowtoconstructbivariatecompactlyorthonormalwaveletsforanygivencompactlysupportedscalingfunction .Thepur poseofthispaperistoconstructcompactlysupportedorthogonalwaveletass… 相似文献
5.
紧支撑正交对称和反对称小波的构造 总被引:10,自引:0,他引:10
1.引言 近年来,人们分别从数学和信号的观点对正交小波进行了广泛的研究.尤其是2尺度小波,它克服了短时 Fourier变换的一些缺陷.目前最常用的 2尺度小波是 Daubechies 小波,但 2尺度小波也存在一些问题:如 Daubechies[2]已证明了除 Haar小波外不存在既正交又对称的紧支撑 2尺度小波.因此人们提出了 a尺度小波理论[3]-[6],文献[4]-[6]对 4尺度小波迸行研究.本文的目的是研究4尺度因子时紧支撑正交对称和反对称小波的构造方法.并指出对同一紧支撑正交对称尺度函数而言,… 相似文献
6.
A general procedure for constructing multivariate non-tensor-product wavelets that generate an orthogonal decomposition ofL
2(R)s,s s≥1, is described and applied to yield explicit formulas for compactly supported spline-wavelets based on the multiresolution
analysis ofL
2(R)s 1≤s≤3, generated by any box spline whose direction set constitutes a unimodular matrix. In particular, when univariate cardinal
B-splines are considered, the minimally supported cardinal spline-wavelets of Chui and Wang are recovered. A refined computational
scheme for the orthogonalization of spaces with compactly supported wavelets is given. A recursive approximation scheme for
“truncated” decomposition sequences is developed and a sharp error bound is included. A condition on the symmetry or anti-symmetry
of the wavelets is applied to yield symmetric box-spline wavelets.
Partially supported by ARO Grant DAAL 03-90-G-0091
Partially supported by NSF Grant DMS 89-0-01345
Partially supported by NATO Grant CRG 900158. 相似文献
7.
何永滔 《纯粹数学与应用数学》2012,(1):8-16
基于Householder矩阵扩充,构造了紧支撑正交的二维小波,所构造小波函数的支撑不超过尺度函数的支撑,并且给出了容易实施的显式构造算法.另外,还通过构造反例说明Riesz定理不适用于二元三角多项式.最后,构造了算例. 相似文献
8.
In this paper, the notion of two-direction vector-valued multiresolution analysis and the two-direction orthogonal vector-valued wavelets are introduced. The definition for two-direction orthogonal vector-valued wavelet packets is proposed. An algorithm for constructing a class of two-direction orthogonal vector-valued compactly supported wavelets corresponding to the two-direction orthogonal vector-valued compactly supported scaling functions is proposed by virtue of matrix theory and time-frequency analysis method. The properties of the two-direction vector-valued wavelet packets are investigated. At last, the direct decomposition relation for space L2(R)r is presented. 相似文献
9.
Orthonormal bases of compactly supported wavelet bases correspond to subband coding schemes with exact reconstruction in which the analysis and synthesis filters coincide. We show here that under fairly general conditions, exact reconstruction schemes with synthesis filters different from the analysis filters give rise to two dual Riesz bases of compactly supported wavelets. We give necessary and sufficient conditions for biorthogonality of the corresponding scaling functions, and we present a sufficient conditions for the decay of their Fourier transforms. We study the regularity of these biorthogonal bases. We provide several families of examples, all symmetric (corresponding to “linear phase” filters). In particular we can construct symmetric biorthogonal wavelet bases with arbitraily high preassigned regularity; we also show how to construct symmetric biorthogonal wavelet bases “close” to a (nonsymmetric) orthonormal basis. 相似文献
10.
Patrick J. Van Fleet 《Journal of Computational Analysis and Applications》2003,5(1):161-178
In many applications of image processing, the given data are integer-valued. It is therefore desirable to construct transformations that map data of this type to an integer (or rational) ring. Calderbank, Daubechies, Sweldens, and Yeo [1] devised two methods for modifying orthogonal and biorthogonal wavelets so that they map integers to integers. The first method involves appropriately scaling the transform so that data that has been transformed and truncated can be recovered via the inverse wavelet transform. In developing this method, the authors of [1] created a useful factorization of the 4-tap Daubechies orthogonal wavelet transform [2]. We have observed that this factorization can be extended to 4-tap multiwavelets of arbitrary size. In this paper we will discuss this generalization and illustrate the factorization on two multiwavelets. In particular, the well-known Donovan, Geronimo, Hardin, and Massopust (DGHM) [3] multiwavelet transform can be scaled so that it maps integers to integers. Since this transform is (anti)symmetric in addition to orthogonal, regular, and compactly supported, the ability to modify it so that it maps integers to integers should be useful in image processing applications. 相似文献
11.
In this paper, a method is developed for constructing compactly supported trivariate orthogonal wavelets from univariate orthogonal wavelets, essential idea of the approach is permutation of conjugate quadrature filter. Nonseparable and separable wavelets can be achieved from univariate orthogonal wavelets. Two examples are given to demonstrate this method. 相似文献
12.
本篇文章给出一类$L^{2}(\mathbb{R}^{n})$, $n\geq2$的紧支撑不可分正交小波基的具体构造算法,其中正交小波的伸缩矩阵为$\alpha I_{n}~(\alpha\geq2,\ \alpha \in \mathbb{Z})$, $I_{n}$是$n$阶单位矩阵.最后给出两个不可分正交小波基的构造算例. 相似文献
13.
Starting from any two compactly supported refinable functions in L2(R)
with dilation factor d,we show that it is always possible to construct 2d wavelet functions
with compact support such that they generate a pair of dual d-wavelet frames in L2(R).
Moreover, the number of vanishing moments of each of these wavelet frames is equal
to the approximation order of the dual MRA; this is the highest possible. In particular,
when we consider symmetric refinable functions, the constructed dual wavelets are also
symmetric or antisymmetric. As a consequence, for any compactly supported refinable
function in L2(R), it is possible to construct, explicitly and easily, wavelets that are
finite linear combinations of translates (d · – k), and that generate a wavelet frame with
an arbitrarily preassigned number of vanishing moments.We illustrate the general theory
by examples of such pairs of dual wavelet frames derived from B-spline functions. 相似文献
14.
15.
CONSTRUCTION OF COMPACTLY SUPPORTED BIVARIATE ORTHOGONAL WAVELETS BY UNIVARIATE ORTHOGONAL WAVELETS 总被引:4,自引:0,他引:4
After some permutation of conjugate quadrature filter, new conjugate quadrature filters can be derived. In terms of this permutation, an approach is developed for constructing compactly supported bivariate orthogonal wavelets from univariate orthogonal wavelets. Non-separable orthogonal wavelets can be achieved. To demonstrate this method, an example is given. 相似文献
16.
In this paper,we introduce matrix-valued multiresolution analysis and orthogonal matrix-valued wavelets.We obtain a necessary and sufficient condition on the existence of orthogonal matrix-valued wavelets by means of paraunitary vector filter bank theory.A method for constructing a class of compactly supported orthogonal matrix-valued wavelets is proposed by using multiresolution analysis method and matrix theory. 相似文献
17.
Martin Ehler 《Journal of Fourier Analysis and Applications》2007,13(5):511-532
In this article, we construct compactly supported multivariate pairs of dual wavelet frames, shortly called bi-frames, for
an arbitrary dilation matrix. Our construction is based on the mixed oblique extension principle, and it provides bi-frames
with few wavelets. In the examples, we obtain optimal bi-frames, i.e., primal and dual wavelets are constructed from a single
fundamental refinable function, whose mask size is minimal w.r.t. sum rule order and smoothness. Moreover, the wavelets reach
the maximal approximation orderw.r.t. the underlying refinable function. For special dilation matrices, we derive very simple
but optimal arbitrarily smooth bi-frames in arbitrary dimensions with only two primal and dual wavelets. 相似文献
18.
对称反对称紧支撑正交多小波的构造 总被引:1,自引:0,他引:1
对于给定的对称反对称紧支撑正交r重尺度函数,给出一种构造对称反对称紧支撑正交多小波的方法.通过此方法构造的多小波与尺度函数有相同的对称性与反对称性,并且给出算例. 相似文献
19.
20.
We study biorthogonal bases of compactly supported wavelets constructed from box splines in ℝ
N
with any integer dilation factor. For a suitable class of box splines we write explicitly dual low-pass filters of arbitrarily
high regularity and indicate how to construct the corresponding high-pass filters (primal and dual).
Received: August 23, 2000; in final form: March 10, 2001?Published online: May 29, 2002 相似文献