共查询到20条相似文献,搜索用时 46 毫秒
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提出两种二进小波的构造方法.首先,将Mallat构造的B-样条二进小波推广得到一种构造B-样条二进小波的新方法;其次,基于二进提升方案提出构造二进小波的另一种新方法一构造定理,并通过调整定理中提升参数的形式、以新的B-样条二进小波作为初始二进小波,具体构造了具有有限长单位脉冲响应、高阶消失矩、线性相位的提升二进小波,这些提升二进小波不能由Sweldens提升方案得到. 相似文献
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1.引言用小波处理实际问题时,对称性具有重要的意义.如果小波不具有对称性,则在信号重构时可能导致失真.我们知道,用多项式滤波器构造的正交小波不具有对称性,这是一个重要的缺欠.本文讨论了分式滤波器,它作为多项式滤波器的最自然的推广和进展,且包含了B样条小波滤波器,可随意构造出对称性小波函数,对实际应用提供了有意义的构造性方法.在小波计算中,为了回避hllrl*r逆变换,人们通常喜欢用Mdl时算法山,即对尺度函数方程为造迭代格式为了得到迭代收敛(n。、v)条件,通常把滤波器其中以及时,迭代格式(2)逐点收敛于尺… 相似文献
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提出了一种二维正交小波滤波器逼近的方法,采用分步优化的方法来构造小波滤波器,最后通过实验给出低通的小波滤波器. 相似文献
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多元小波滤波器的矩阵扩充 总被引:1,自引:1,他引:0
该文讨论了多元小波滤波器的矩阵扩充问题.文献[7]给出了当伸缩矩阵为2I2×2时的矩阵扩充方法,该文得出了当伸缩矩阵A满足detA=4时的方法. 相似文献
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周建锋 《数学的实践与认识》2014,(3)
研究由三元双正交插值尺度函数构造对应的双正交小波滤波器的矩阵扩充问题.当给定的一对三元双正交尺度函数中有一个为插值函数时,利用提升思想与矩阵多相分解方法,给出一类三元双正交小波滤波器的显示构造公式和一个计算实例.讨论了三元双正交小波包的的性质. 相似文献
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本文给出了多小波框架的sub-QMF条件,提出了多小波框架低通滤波器的参数化设计,由正交分解和矩阵的酉扩张得到其相应的高通滤波器表示的整套多小波框架设计的参数化方法,同时针对多描述编码的需求,构造了两个长折叠对称带参数的多小波紧框架. 相似文献
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We give a construction, for any n 2, of a space S
of spline functions of degree n – 1 with simple knots in (1/4)Z
which is generated by a triple of refinable, orthogonal functions with
compact support. Indeed, the result holds more generally by replacing the
B-spline of degree n – 1 with simple knots at the integers by any
continuous refinable function whose mask is a Hurwitz polynomial of
degree n. A simple construction is also given for the corresponding
wavelets. 相似文献
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林海 《数学的实践与认识》2009,39(3)
挖掘最大频繁项集是多种数据挖掘应用中的关键问题.针对频繁模式挖掘的可扩展性问题,基于Bloom Filter的相关理论,提出了一种"挖掘最频繁的K个元素"的Mining Top-K算法.该算法基于推广的Bloom Filter的数据结构,能够较为准确地筛选出数据流中出现最频繁的K个元素,并估算这K个元素的出现频数.实验结果表明:该方法在具有低空间复杂度特性的同时又不会失去准确性. 相似文献
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It is proved that the filter dimension is Morita invariant. A direct consequence of this fact is the Morita invariance of the inequality of Bernstein: if an algebra A is Morita equivalent to the ring of differential operators on a smooth irreducible affine algebraic variety X of dimension n ≥ 1 over a field of characteristic zero then the Gelfand–Kirillov dimension for all nonzero finitely generated A-modules M. In fact, a stronger result is proved, namely, a Morita invariance of the holonomic number for finitely generated algebra. A direct consequence of this fact is that an analogue of the inequality of Bernstein holds for the (simple) rational Cherednik algebras
H
c
for integral
c:
for all nonzero finitely generated H
c
-modules
M. For these class of algebras, it gives an affirmative answer to a question of Ken Brown about symplectic reflection algebras.
Presented by Alain Verschoren. 相似文献
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结合有效集和多维滤子技术的拟Newton信赖域算法(英文) 总被引:1,自引:0,他引:1
针对界约束优化问题,提出一个修正的多维滤子信赖域算法.将滤子技术引入到拟Newton信赖域方法,在每步迭代,Cauchy点用于预测有效集,此时试探步借助于求解一个较小规模的信赖域子问题获得.在一定条件下,本文所提出的修正算法对于凸约束优化问题全局收敛.数值试验验证了新算法的实际运行结果. 相似文献
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在指纹图像识别过程中,指纹图像的滤波去噪音二值化和指纹特征的匹配是最关键的两个部分.本文针对这两部分的算法设计进行分析和改进,介绍利用B样条造型来设计指纹滤波模板的方法和基于基准点附近的拓扑结构进行快速特征匹配的算法.并且利用改进后的指纹特征匹配算法,在样本指纹库中进行实验,结果表明该算法大大提高了指纹特征匹配的效率和准确性. 相似文献
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The notion of a frame multiresolution analysis (FMRA) is formulated. An FMRA is a natural extension to affine frames of the classical notion of a multiresolution analysis (MRA). The associated theory of FMRAs is more complex than that of MRAs. A basic result of the theory is a characterization of frames of integer translates of a function φ in terms of the discontinuities and zero sets of a computable periodization of the Fourier transform of φ. There are subband coding filter banks associated with each FMRA. Mathematically, these filter banks can be used to construct new frames for finite energy signals. As with MRAs, the FMRA filter banks provide perfect reconstruction of all finite energy signals in any one of the successive approximation subspacesVjdefining the FMRA. In contrast with MRAs, the perfect reconstruction filter bank associated with an FMRA can be narrow band. Because of this feature, in signal processing FMRA filter banks achieve quantization noise reduction simultaneously with reconstruction of a given narrow-band signal. 相似文献
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Peer-to-Peer(P2P)环境下的信用管理对鼓励节点间的资源共享和抵制恶意节点的行为有重要的作用.针对目前P2P信用管理系统中全局信用值需要迭代计算,网络通信开销较大等问题,借鉴多传感器目标跟踪中的信息融合思想,提出了一种新的P2P环境下信用管理机制.建立了节点信用变化方程和测量方程,给出了节点全局信用值的分布式Kalman滤波估计方法,并讨论了恶意节点抑制问题.理论分析和仿真计算表明本文方法的信用值计算精度高、收敛速度快、资源开销小、对动态节点的适应性强并具有很好的可扩充性. 相似文献
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Wave atoms and sparsity of oscillatory patterns 总被引:4,自引:0,他引:4
We introduce “wave atoms” as a variant of 2D wavelet packets obeying the parabolic scaling wavelength(diameter)2. We prove that warped oscillatory functions, a toy model for texture, have a significantly sparser expansion in wave atoms than in other fixed standard representations like wavelets, Gabor atoms, or curvelets. We propose a novel algorithm for a tight frame of wave atoms with redundancy two, directly in the frequency plane, by the “wrapping” technique. We also propose variants of the basic transform for applications in image processing, including an orthonormal basis, and a shift-invariant tight frame with redundancy four. Sparsity and denoising experiments on both seismic and fingerprint images demonstrate the potential of the tool introduced. 相似文献