排序方式: 共有172条查询结果,搜索用时 15 毫秒
31.
杨建伟 《河南师范大学学报(自然科学版)》2003,31(3):18-21
本给出一种任意伸缩矩阵正交小波包构造方法.该小波包是以频域形式给出的,献[1]所给小波包仅是其一特例.这样所得的小波包使得L^2(R^s)中小波基的选择更灵活,最后给出算例. 相似文献
32.
研究多变量向量值双正交多小波包的构造与性质.引进了向量值多分辨分析与多变量值双正交多重小波的概念.给出多变量多重向量值双正交小波包的定义及其迭代方法.运用积分变换与有限群理论,讨论了多变量多重向量值双正交小波包的性质,得到了多变量多重向量值双正交小波包的双正交公式,进而给出多变量向量值函数空间L2(Rs,Cn)的一个新的基底. 相似文献
33.
针对多小渡理论在图像处理领域的应用,给出了多小波域中图像的方向对比度的定义,并提出了基于多小波变换的、使用方向对比度进行自适应加权平均融合和选择性融合的算法.该算法利用多小渡变换对原图像进行分解,根据得到的分解系数计算相应的对比度,然后建立基于对比度的融合规则.使用这些算法对多谱图像进行了融合实验,并给出了评价融合质量的对比结果.结果表明,基于多小波变换的方向对比度的图像融舍算法在保留图像细节信息、增加信息量方面都有明显的提高. 相似文献
34.
通过建立自动关联函数以及将波函数扩展为一系列的次波函数的叠加的方法,研究了在大于恢复时间trev时氢原子Rydberg波包的行为特征。大于恢复时间trev时,氢原子Rydberg波包在经历几个周期的恢复之后,在恢复时间的整数倍时停止原来的恢复,而开始一系列新的坍塌和恢复。这种新恢复的周期是tsr(tsr〉〉trev)。在tsr时刻形成的波包比trev时刻形成的波包更接近初始波包。本文利用自动关联函数以及波函数与次波函数的关系对这种现象进行了研究。 相似文献
35.
给出数量矩阵mIr(2≤m∈Z)伸缩的多元向量值小波包的定义及其构造方法.运用代数学理论,算子理论与时频分析方法,讨论多元向量值小波包的正交性,得到多元向量值小波包的正交公式. 相似文献
36.
P. MERCORELLI 《系统科学与复杂性》2007,20(3):325-343
New industrial applications call for new methods and new ideas in signal analysis. Wavelet packets are new tools in industrial
applications and they have just recently appeared in projects and patents. In training neural networks, for the sake of dimensionality
and of ratio of time, compact information is needed. This paper deals with simultaneous noise suppression and signal compression
of quasi-harmonic signals. A quasi-harmonic signal is a signal with one dominant harmonic and some more sub harmonics in superposition.
Such signals often occur in rail vehicle systems, in which noisy signals are present. Typically, they are signals which come
from rail overhead power lines and are generated by intermodulation phenomena and radio interferences. An important task is
to monitor and recognize them. This paper proposes an algorithm to differentiate discrete signals from their noisy observations
using a library of nonorthonormal bases. The algorithm combines the shrinkage technique and techniques in regression analysis
using Shannon Entropy function and Cross Entropy function to select the best discernable bases. Cosine and sine wavelet bases
in wavelet packets are used. The algorithm is totally general and can be used in many industrial applications. The effectiveness
of the proposed method consists of using as few as possible samples of the measured signal and in the meantime highlighting
the difference between the noise and the desired signal. The problem is a difficult one, but well posed. In fact, compression
reduces the level of the measured noise and undesired signals but introduces the well known compression noise. The goal is
to extract a coherent signal from the measured signal which will be “well represented” by suitable waveforms and a noisy signal
or incoherent signal which cannot be “compressed well” by the waveforms. Recursive residual iterations with cosine and sine
bases allow the extraction of elements of the required signal and the noise. The algorithm that has been developed is utilized
as a filter to extract features for training neural networks. It is currently integrated in the inferential modelling platform
of the unit for Advanced Control and Simulation Solutions within ABB’s industry division. An application using real measured
data from an electrical railway line is presented to illustrate and analyze the effectiveness of the proposed method. Another
industrial application in fault detection, in which coherent and incoherent signals are univocally visible, is also shown. 相似文献
37.
IPv4向IPv6迁移的过渡策略 总被引:6,自引:0,他引:6
随着Internet的发展,IPv4的问题逐渐显露出来,IETF开发的IPv6基本能解决这些问题,所以从IPv4向IPv6过渡已成为必然,这里论述了IPv4的局限性及IPv6的提出,介绍了IPv6协议的特点,给出了IPv6过渡的策略,尤其是隧道技术。 相似文献
38.
多元多重向量值正交小波包的性质 总被引:1,自引:0,他引:1
推广了多元正交小波包的概念,给出了多元多重向量值正交小波包的定义及其构造方法.讨论了这种向量值小波包的性质,由此得到空间L2(Rn,Cr×r)的一组新的正交基. 相似文献
39.
将平衡多小波的概念引入到M带r重双正交多小波系统,给出了相应的平衡条件,建立了M带r重双正交多尺度函数的若干等价关系,并基于这些等价关系给出构造双正交平衡多尺度函数和多小波的算法.算法在处理离散的多项式信号时,信号既能被低通滤波器保持,又能被高通滤波器取消,同时算法还保持了双正交多小渡的对称性,这一点在信号处理方面具有很好的应用价值. 相似文献
40.
研究向量值双正交小波包,给出一类紧支撑向量值双正交小波包的定义及其构造方法.讨论了这种向量值双正交小波包的性质. 相似文献