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复解析小波变换与语音信号包络提取和分析 总被引:21,自引:2,他引:19
利用传统的Hilbert变换方法提取语音信号包络存在一些固有缺陷,为此本文建议了一种复解析小波变换包络提取新方法。该方法将Hilbert分析与小波分析紧密地结合在一起。文中推导并论述了新包络滤波器的时域、频域构造条件和设计方法,选择Morlet复小波对语音信号进行了初步数字仿真实验,结果证实了理论分析的正确性,并显示出文中提出的新的分析方法对于信号处理上有许多独特优势和潜在性能。 相似文献
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针对单视觉唇读系统中唇部特征的提取问题,提出了基于双树复小波和PCA的唇部特征提取方法.利用双树复小波变换的近似平移不变性,通过将变换后的系数幅值重新排列,克服了感兴趣区域中唇部偏移的影响.与DCT相比.双树复小波变换既可反映输入信号的频域特性,又能反映其空间域特性,具有近似平移不变性.这些特性使得DT-CWT+PCA... 相似文献
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基于小波分析的迎角传感器信号预处理 总被引:1,自引:0,他引:1
针对基于四象限压力传感器阵列的迎角测量方法中,传感器信号受到干扰的问题,讨论了在其预处理中应用小波变换进行信号分离提取的方法.根据小波分解理论,对信号进行多尺度的小波变换,信号中频率不同的部分落在不同的尺度上,剔除反映干扰的小波变换尺度,提取出有用信息.结果表明,该方法可较好地提取信号的主要特征信息,有效的去除了确定性干扰和随机噪声,与传统的信号滤波方法相比较具有明显的优点,同时为后续的信号处理奠定了基础. 相似文献
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小波变换的局部谱特征 总被引:1,自引:1,他引:0
小波变换因其固有的多分辨能力而受到人们的青睐,但其变换结果却缺乏直观的物理意义。笔者经过一系列的推导,揭示出实信号的实小波变换结果缺乏直观性的根源。进而指出,以复解析小波为母小波的尺度图具有直观的物理意义,它反映的就是信号的局部频谱信息。据此,就几种典型信号给出了以实小波及复解析小波为母小波时的尺度图比较。结果表明,由复解析小波交换所得尺度图也更有利于信号瞬变时刻的准确定位。 相似文献
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采用二次小波变换自动阈值算法对局部放电信号进行提取。在数值仿真中,采用指数衰减或指数衰减振荡等4种放电信号,研究了局部放电信号的提取效果。仿真结果表明,由于小波变换具有多分辨率的特性,能有效地从随机噪声中提取出放电信号,较常规一次小波变换阈值消噪方法相比,二次小波变换更多地保留了原始局部放电信号的特征信息,该算法处理速度较快,也适合在线处理。 相似文献
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信号的指纹特征是辐射源个体识别的重要依据。针对敌我识别辐射源的个体识别问题,提出了一种基于双树复小波和多重分形的信号暂态特征提取方法。该方法通过双树复小波变换实现信号多分辨率分解,求解分解信号Hilbert谱的信息熵和指数熵,计算信号的多重分形奇异指数和谱值,最终组成表征辐射源的特征向量。通过实验验证,提取的特征向量能充分代表辐射源个体之间的差异;被测信号的信噪比满足8 dB或9 dB的条件时,对辐射源的识别正确率能达到90%以上。统计分析表明该方法提取的特征具有很高的稳定性。 相似文献
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A Shearlet Approach to Edge Analysis and Detection 总被引:7,自引:0,他引:7
It is well known that the wavelet transform provides a very effective framework for analysis of multiscale edges. In this paper, we propose a novel approach based on the shearlet transform: a multiscale directional transform with a greater ability to localize distributed discontinuities such as edges. Indeed, unlike traditional wavelets, shearlets are theoretically optimal in representing images with edges and, in particular, have the ability to fully capture directional and other geometrical features. Numerical examples demonstrate that the shearlet approach is highly effective at detecting both the location and orientation of edges, and outperforms methods based on wavelets as well as other standard methods. Furthermore, the shearlet approach is useful to design simple and effective algorithms for the detection of corners and junctions. 相似文献
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Melnik V.P. Shmulevich I. Egiazarian K. Astola J. 《Signal Processing, IEEE Transactions on》2001,49(2):364-372
A nonlinear multiscale pyramidal transform based on nonoverlapping block decompositions using the median operation and a polynomial approximation is considered. It is shown that this structure can be useful for denoising of oneand two-dimensional (1-D and 2-D) signals. Various denoising techniques are analyzed, including methods based on spatially adaptive thresholding and partial cycle-spinning algorithms. An analytical method for deriving the distribution function of the transform coefficients is also presented. This, in turn, can be used for the selection of thresholds for denoising applications 相似文献
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Optimizing the multiwavelet shrinkage denoising 总被引:3,自引:0,他引:3
Denoising methods based on wavelet domain thresholding or shrinkage have been found to be effective. Recent studies reveal that multivariate shrinkage on multiwavelet transform coefficients further improves the traditional wavelet methods. It is because multiwavelet transform, with appropriate initialization, provides better representation of signals so that their difference from noise can be clearly identified. We consider the multiwavelet denoising by using multivariate shrinkage function. We first suggest a simple second-order orthogonal prefilter design method for applying multiwavelet of higher multiplicities. We then study the corresponding thresholds selection using Stein's unbiased risk estimator (SURE) for each resolution level provided that we know the noise structure. Simulation results show that higher multiplicity wavelets usually give better denoising results and the proposed threshold estimator suggests good indication for optimal thresholds. 相似文献
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一种新的3-D小波变换图像编码方法 总被引:2,自引:0,他引:2
基于图像序列三维小波变换的视频编码技术是一种很有潜力的编码方法.本文针对目前实际中采用的三维小波变换只是一种准三维变换,不能提供对变换结果的统一描述等不足,推导了信号真正的三维小波变换的有关理论及其实现方法.在此基础上,我们将这种三维小波变换方法用于视频图像的编码,模拟结果表明这种编码结构具有良好性能,值得进一步的深入研究. 相似文献
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小波变换和AR模型在脑电信号处理中的应用 总被引:1,自引:0,他引:1
谈论了基于小波变换和AR模型的(EEG)信号的分析方法,在两种方法相结合的情况下,能有效消去(EEG)信号的噪声。用小波变换对含有瞬态干扰的脑电信号进行多尺度分解,在某些尺度下,瞬态信号特征得以明显增强,用简单的阈值比较就可以有效地检测并消除瞬态干扰。最后在Matlab环境下进行仿真实验,验证了此方法在提取脑电信号中的有效性。 相似文献
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Diffraction calculations using fast Fourier transform methods 总被引:5,自引:0,他引:5
By using a coordinate transformation based on Gaussian-beam theory, we can apply efficient fast Fourier transform (FFT) computational methods to diffraction problems involving spherically diverging or converging waves as well as to quasi-collimated beams of radiation. 相似文献
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