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  • Matlab下小波分析wavelet常用命令

    千次阅读 2013-07-01 16:24:35
    Matlab下小波分析wavelet常用命令 分类: Math & Algorithm 转自: redoc http://blog.chinaunix.net/space.php?uid=7817741 一维的情况下: 单尺度 分解: [ca1,cd1]=dwt(signal,wavelet'); //signal是被分析的...
    转自:
    redoc

    http://blog.chinaunix.net/space.php?uid=7817741



    一维的情况下:

    单尺度

    分解:

    [ca1,cd1]=dwt(signal,wavelet'); //signal是被分析的信号,wavelet是小波类型,ca1是低频系数,cd1是高频系数。

    重构:

    A1=upcoef('a',ca1,wavelet,1,l_s);//参数'a'表示近似系数(低频)的重构,如果是'd'表示细节系数(高频)的重构,l_s是信号的长度

    s=idwt(ca1,cd1,wavelet,l_s);

    多尺度

    分解:

    [c,l]=wavedec(signal,maxlevel,wavelet);//参数maxlevel是多尺度分解的层数,输出c是系数,l是系数的排列信息

    对系数的一些操作可以用函数wthcoef(),比如设置细节系数为0等。提取系数的函数: appcoef()和detcoef()分别提取近似系数和细节系数。

    c=wthcoef('d',c,l,[2,3]);//设置尺度2,3下的细节分量为0

    ca3=appcoef(c,l,wavelet,3);//提取尺度3下的近似系数

    cd3=detcoef(c,l,3);//提取尺度3下的细节系数

    重构:

    重构整个信号

    s=waverec(c,l,wavelet);

    重构细节信号

    s=wrcoef('d',c,l,'db1',3);//重构尺度3下的细节信号

    重构近似信号

    s=wrcoef('a',c,l,'db1',3);//重构尺度3下的近似信号

    二维情况下:

    单尺度:

    分解:

    [ca1,ch1,cv1,cd1]=dwt2(signal,'db1');//输出ca1是近似系数,ch1是水平细节系数,cv1是垂直细节系数,cd1是对角细节系数

    重构:

    s=upcoef2('a',ca1,'db1',1);//根据ca1重构尺度1下的近似信号

    s=idwt2(ca1,ch1,cv1,cd1,'db1');

    多尺度:

    分解:

    [c,s]=wavedec2(x,2,'db1');//对信号x进行2尺度的分解,系数在c中,系数的结构说明在s中。

    appcoef2()和detcoef2()用来取得不同尺度下的近似系数和细节系数。

    wrcoef2()根据近似系数或细节系数重构信号

    展开全文
  • matlab小波分解及小波包分解函数

    千次阅读 2018-11-06 14:36:53
    Wavelet Toolbox GUI (Graphical User Interface).  waveletAnalyzer - Start Wavelet Analyzer graphical user interface tools    Wavelets: General  biorfilt - Biorthogonal wavelet filter set ...

    Wavelet Toolbox GUI (Graphical User Interface).
        waveletAnalyzer - Start Wavelet Analyzer graphical user interface tools
     
      Wavelets: General
        biorfilt        - Biorthogonal wavelet filter set
        centfrq         - Wavelet center frequency
        dyaddown        - Dyadic downsampling
        cwtfilterbank   - CWT filter bank
        dwtfilterbank   - DWT filter bank
        dyadup          - Dyadic upsampling
        intwave         - Integrate wavelet function psi
        orthfilt        - Orthogonal wavelet filter set
        qmf             - Quadrature mirror filter
        scal2frq        - Scale to frequency
        wavefun         - Wavelet and scaling functions
        wavefun2        - Wavelets and scaling functions 2-D
        wavemngr        - Wavelet manager 
        wfilters        - Wavelet filters
        wmaxlev         - Maximum wavelet decomposition level
     
      Wavelet Families
        biorwavf        - Biorthogonal spline wavelet filters
        cgauwavf        - Complex Gaussian wavelet
        cmorwavf        - Complex Morlet wavelet
        coifwavf        - Coiflet wavelet filter
        dbaux           - Daubechies wavelet filter computation
        dbwavf          - Daubechies wavelet filters
        fbspwavf        - Complex Frequency B-Spline wavelet
        fejerkorovkin   - Fejer-Korovkin wavelet filters
        gauswavf        - Gaussian wavelet
        mexihat         - Mexican Hat wavelet
        meyer           - Meyer wavelet
        meyeraux        - Meyer wavelet auxiliary function
        morlet          - Morlet wavelet
        rbiowavf        - Reverse Biorthogonal spline wavelet filters
        shanwavf        - Complex Shannon wavelet
        symaux          - Symlet wavelet filter computation
        symwavf         - Symlet wavelet filter
     
      Time-Frequency Analysis/Synthesis
        cqt             - Constant-Q transform using nonstationary Gabor frames
        icqt            - Inverse constant-q transform using nonstationary Gabor frames
        cwtft           - Continuous wavelet transform using DFT
        cwtftinfo       - Information on wavelets for CWTFT
        cwtfreqbounds   - CWT maximum and minimum period or frequency 
        cwt             - Continuous wavelet transform
        icwt            - Inverse continuous wavelet transform
        pat2cwav        - Construction of a wavelet starting from a pattern
        wcoherence      - Wavelet coherence
        wsst            - Wavelet synchrosqueezing transform
        iwsst           - Inverse wavelet synchrosqueezing transform
        wsstridge       - Time-frequency ridges from wavelet synchrosqueezing
        wtmm            - Wavelet transform modulus maxima
        cwtfilterbank   - CWT filter bank
        wscalogram      - Scalogram for continuous wavelet transform
     
      Continuous Wavelet: Two-Dimensional
        cwtft2      - 2-D Continuous wavelet transform
        cwtftinfo2  - Information on wavelets for CWTFT2
     
      Discrete Wavelets: One-Dimensional
        appcoef         - Extract 1-D approximation coefficients
        detcoef         - Extract 1-D detail coefficients
        dwt             - Single-level discrete 1-D wavelet transform
        dwtfilterbank   - DWT filter bank
        dwtmode         - Discrete wavelet transform extension mode
        idwt            - Single-level inverse discrete 1-D wavelet transform
        haart           - Haar 1-D transform
        ihaart          - Inverse Haar 1-D transform
        upcoef          - Direct reconstruction from 1-D wavelet coefficients
        upwlev          - Single-level reconstruction of 1-D wavelet decomposition
        wavedec         - Multilevel 1-D wavelet decomposition
        waverec         - Multilevel 1-D wavelet reconstruction
        wenergy         - Energy for 1-D wavelet decomposition
        wrcoef          - Reconstruct single branch from 1-D wavelet coefficients
     
      Maximal Overlap Discrete Wavelet Transform
        modwt         - Maximal overlap discrete wavelet transform
        imodwt        - Inverse maximal overlap discrete wavelet transform
         modwtmra    - Maximal overlap discrete wavelet transform MRA
         modwtcorr    - Maximal overlap discrete wavelet transform correlation
         modwtvar    - Maximal overlap discrete wavelet transform variance
         modwtxcorr    - Maximal overlap discrete wavelet transform cross-correlation sequences
     
      Maximal Overlap Discrete Wavelet Packet Transform
        modwpt          -   Maximal overlap discrete wavelet packet transform
        imodwpt         -   Inverse maximal overlap discrete wavelet packet transform
        modwptdetails   -   Maximal overlap discrete wavelet packet details
     
      Multiscale Local Polynomial Transform: One-Dimensional
        mlpt            -   Multiscale local polynomial transform
        imlpt           -   Inverse multiscale local polynomial transform
        mlptrecon       -   Multiscale 1-D Local Polynomial Transform Reconstruction 
        mlptdenoise     -   Denoising using the Multiscale local 1-D Polynomial Transform
        
      Discrete Wavelets: Two-Dimensional
        appcoef2    - Extract 2-D approximation coefficients
        detcoef2    - Extract 2-D detail coefficients
        dwt2        - Single-level discrete 2-D wavelet transform
        dwtmode     - Discrete wavelet transform extension mode
         haart2        - Haar 2-D transform
        idwt2       - Single-level inverse discrete 2-D wavelet transform
         ihaart2        - Inverse Haar 2-D transform
        upcoef2     - Direct reconstruction from 2-D wavelet coefficients
        upwlev2     - Single-level reconstruction of 2-D wavelet decomposition
        wavedec2    - Multi-level 2-D wavelet decomposition
        waverec2    - Multi-level 2-D wavelet reconstruction
        wenergy2    - Energy for 2-D wavelet decomposition
        wrcoef2     - Reconstruct single branch from 2-D wavelet coefficients
     
      Discrete Wavelets: Three-Dimensional
        dwt3        - Single-level discrete 3-D wavelet transform
        dwtmode     - Discrete wavelet transform extension mode
        idwt3       - Single-level inverse discrete 2-D wavelet transform
        wavedec3    - Multi-level 3-D wavelet decomposition
        waverec3    - Multi-level 3-D wavelet reconstruction
     
      Wavelets Packets Algorithms
        bestlevt    - Best level tree (wavelet packet)
        besttree    - Best tree (wavelet packet)
        entrupd     - Entropy update (wavelet packet)
        wenergy     - Energy for a wavelet packet decomposition
        wentropy    - Entropy (wavelet packet)
        wp2wtree    - Extract wavelet tree from wavelet packet tree
        wpcoef      - Wavelet packet coefficients
        wpcutree    - Cut wavelet packet tree
        wpdec       - Wavelet packet decomposition 1-D
        wpdec2      - Wavelet packet decomposition 2-D
        wpfun       - Wavelet packet functions
        wpjoin      - Recompose wavelet packet
        wprcoef     - Reconstruct wavelet packet coefficients
        wprec       - Wavelet packet reconstruction 1-D 
        wprec2      - Wavelet packet reconstruction 2-D
        wpsplt      - Split (decompose) wavelet packet
     
      Discrete Stationary Wavelet Transform Algorithms

        iswt        - Inverse discrete stationary wavelet transform 1-D
        iswt2       - Inverse discrete stationary wavelet transform 2-D
        swt         - Discrete stationary wavelet transform 1-D
        swt2        - Discrete stationary wavelet transform 2-D
     
      Multisignal Wavelet Analysis: One-Dimensional
        chgwdeccfs  - Change Multisignal 1-D decomposition coefficients
        mdwtdec     - Multisignal 1-D wavelet decomposition 
        mdwtrec     - Multisignal 1-D wavelet reconstruction 
        mswcmp      - Multisignal 1-D compression using wavelets 
        mswcmpscr   - Multisignal 1-D wavelet compression scores
        mswcmptp    - Multisignal 1-D compression thresholds and performances
        mswden      - Multisignal 1-D denoising using wavelets 
        mswthresh   - Performs Multisignal 1-D thresholding 
        wdecenergy  - Multisignal 1-D decomposition energy repartition 
        wmspca      - Multiscale principal component analysis 
        wmulden     - Wavelet multivariate 1-D denoising 
     
      Lifting Functions
        addlift     - Adding primal or dual lifting steps
        bswfun      - Biorthogonal scaling and wavelet functions
        displs      - Display lifting scheme
        filt2ls     - Filters to lifting scheme
        ilwt        - Inverse 1-D lifting wavelet transform
        ilwt2       - Inverse 2-D lifting wavelet transform
        liftfilt    - Apply elementary lifting steps on filters
        liftwave    - Lifting scheme for usual wavelets
        lsinfo      - Information about lifting schemes
        lwt         - Lifting wavelet decomposition 1-D
        lwt2        - Lifting wavelet decomposition 2-D
        lwtcoef     - Extract or reconstruct 1-D LWT wavelet coefficients
        lwtcoef2    - Extract or reconstruct 2-D LWT wavelet coefficients
        wave2lp     - Laurent polynomial associated to a wavelet
        wavenames   - Wavelet names information
     
      Laurent Polynomial [OBJECT in @laurpoly directory]
        laurpoly    - Constructor for the class LAURPOLY (Laurent Polynomial)
     
      Laurent Matrix [OBJECT in @laurmat directory]
        laurmat     - Constructor for the class LAURMAT (Laurent Matrix)
     
      Denoising and Compression for Signals and Images
        cmddenoise              - Command line interval dependent denoising
        ddencmp                 - Default values for denoising or compression
        thselect                - Threshold selection for denoising
        wbmpen                  - Penalized threshold for wavelet 1-D or 2-D denoising
        wdcbm                   - Thresholds for wavelet 1-D using Birge-Massart strategy
        wdcbm2                  - Thresholds for wavelet 2-D using Birge-Massart strategy
        wdenoise                - Wavelet signal denoising
        wden                    - Automatic 1-D denoising using wavelets
        wdencmp                 - Denoising or compression using wavelets
        wnoise                  - Generate noisy wavelet test data
        wnoisest                - Estimate noise of 1-D wavelet coefficients
        wpbmpen                 - Penalized threshold for wavelet packet denoising
        wpdencmp                - Denoising or compression using wavelet packets
        wpthcoef                - Wavelet packet coefficients thresholding
        waveletSignalDenoiser   - Wavelet signal denoiser app
        wthcoef                 - Wavelet coefficient thresholding 1-D
        wthcoef2                - Wavelet coefficient thresholding 2-D
        wthresh                 - Perform soft or hard thresholding
        wthrmngr                - Threshold settings manager
     
      Other Wavelet Applications
        dwtleader    - Multifractal 1-D wavelet leader estimates
        wfbm        - Synthesize fractional Brownian motion
        wfbmesti    - Estimate fractal index
        wfusimg     - Fusion of two images
        wfusmat     - Fusion of two matrices or arrays
     
      Tree Management Utilities
        allnodes    - Tree nodes
        cfs2wpt     - Wavelet packet tree construction from coefficients
        depo2ind    - Node depth-position to node index
        disp        - Display information of WPTREE object
        drawtree    - Draw wavelet packet decomposition tree (GUI)
        dtree       - Constructor for the class DTREE
        get         - Get tree object field contents
        ind2depo    - Node index to node depth-position
        isnode      - True for existing node
        istnode     - Determine indices of terminal nodes
        leaves      - Determine terminal nodes
        nodeasc     - Node ascendants
        nodedesc    - Node descendants
        nodejoin    - Recompose node
        nodepar     - Node parent
        nodesplt    - Split (decompose) node
        noleaves    - Determine nonterminal nodes
        ntnode      - Number of terminal nodes
        ntree       - Constructor for the class NTREE
        plot        - Plot tree object
        read        - Read values in tree object fields
        readtree    - Read wavelet packet decomposition tree from a figure
        set         - Set tree object field contents
        tnodes      - Determine terminal nodes (obsolete - use LEAVES)
        treedpth    - Tree depth
        treeord     - Tree order
        wptree      - Constructor for the class WPTREE
        wpviewcf    - Plot wavelet packets colored coefficients
        write       - Write values in tree object fields
        wtbo        - Constructor for the class WTBO
        wtreemgr    - NTREE object manager
     
      General Utilities
        localmax    - Compute local maxima positions   
        wcodemat    - Extended pseudocolor matrix scaling
        wextend     - Extend a Vector or a Matrix
        wkeep       - Keep part of a vector or a matrix
        wrev        - Flip vector
        wtbxmngr    - Wavelet Toolbox manager
     
      Other
        wvarchg     - Find variance change points
     
      Wavelets Information
        waveinfo        - Information on wavelets
        waveletfamilies - Wavelet families and family members 

    展开全文
  • Matlab 利用小波计算相关性

    千次阅读 2019-08-02 08:25:56
    modwtcorr: Multiscale correlation using the maximal overlap discrete wavelet transform ...Wavelet cross-correlation sequence estimates using the maximal overlap discrete wavelet transform (MO...

    MATLAB帮助:https://ww2.mathworks.cn/help/wavelet/ref/modwtxcorr.html?s_tid=doc_ta
    modwtcorr:
    Multiscale correlation using the maximal overlap discrete wavelet transform

    modwtxcorr:
    Wavelet cross-correlation sequence estimates using the maximal overlap discrete wavelet transform (MODWT)

    相干性与相关性的区别:相干性多用于频域计算,可以在基于频率上给出更多的信息。

    展开全文
  • 离散小波变换---matlab

    千次阅读 2019-03-15 10:52:53
    离散小波变换(Discrete Wavelet Transformation) 一、定义: 首先我们定义一些需要用到的信号及滤波器。 x[n]:离散的输入信号,长度为N。 g[n]:low pass filter低通滤波器,可以将输入信号的高频部份滤掉而输出...

    离散小波变换(Discrete Wavelet Transformation)

    一、定义:

    首先我们定义一些需要用到的信号及滤波器。
    x[n]:离散的输入信号,长度为N。
    g[n]:low pass filter低通滤波器,可以将输入信号的高频部份滤掉而输出低频部份。
    h[n]:high pass filter高通滤波器,与低通滤波器相反,滤掉低频部份而输出高频部份。
    \downarrow Q:downsampling filter降采样滤波器,如果以x[n]作为输入,则输出y[n]=x[Qn]。此处举例Q=2
    在这里插入图片描述
    清楚规定以上符号之后,便可以利用阶层架构来介绍如何将一个离散信号作离散小波变换:
    在这里插入图片描述

    在这里插入图片描述
    在小波分析中经常用到近似和细节,近似表示信号的低尺度,即低频信息;细节表示信号的高尺度,即高频信息。

    matlab

    1 一维小波变换的 Matlab 实现

    (1) dwt函数
    功能:一维离散小波变换
    在这里插入图片描述
    (2) idwt 函数
    功能:一维离散小波反变换
    在这里插入图片描述
    2 二维小波变换的 Matlab 实现

    二维小波变换的函数别可以实现一维、二维和 N 维 DFT

    在这里插入图片描述
    仅介绍wavedec

    wavedec2 函数
    功能:二维信号的多层小波分解1. 离散傅立叶变换的 Matlab实现
    在这里插入图片描述
    用指定的分解低通和高通滤波器 Lo_D 和 Hi_D 分解信号 X 。分别可以实现一维、二维和 N 维 DFT

    waverec2 函数

    说明:二维信号的多层小波重构
    在这里插入图片描述

    展开全文
  • matlab中添加路径和删除路径

    千次阅读 2018-10-10 21:08:09
    参考: ...我们知道,在matlab里添加路径和删除路径可以直接使用【设置路径】这一个选项添加路径和删除路径。但是这样操作的缺点就是,1、对路径的影响是永久性的;2、无法...
  • Matlab一维小波分解流程

    千次阅读 2020-06-07 23:00:46
    Matlab一维小波分解流程Matlab一维小波分解流程1.将待分解变量x放入工作空间。2.在命令窗口输入wavemenu。3.在弹出的对话框里选择One-Dimensional->Wavelet-1-D。4.在弹出的对话框里选择File->Import from ...
  • MATLAB 之 wavedec2函数详解

    千次阅读 2017-11-20 15:17:18
    1.功能:实现图像(即二维信号)的多层分解,多层,即多尺度. 2.格式:[c,s]=wavedec2(X,N,'wname')  [c,s]=wavedec2(X,N,Lo_D,Hi_D)(我不讨论它) 3.参数说明:对图像X用wname小波基函数实现N层分解, 这里的...
  • 利用小波工具箱进行脑电降噪

    千次阅读 2018-03-30 09:16:44
     打开小波工具箱,在MATLAB命令行窗口输入:wavemenu 2. 选中wavelet 1-D,进行离散小波一维信号处理 3. 加载信号,File--->Load--->Signal4. 然后选择母小波,与脑电信号比较匹配的是DB小波,...
  • Wavelet_Matlab.m

    2020-07-30 23:31:09
    基于小波包的模拟电路故障MATLAB
  • In this Augest, I began to learn wavelet for my project.During the learning,I searched many matreials, and found some very useful listed below.Some useful webs :http://www.multires.caltech.edu/tea
  • MATLAB最小化安装

    千次阅读 2017-07-19 17:24:55
    MATLAB Simulink
  • morlet小波程序 matlab

    千次阅读 2016-10-08 14:44:03
    d=-6; h=6; n=100; [g1,x]=morlet(d,h,n); subplot(2,2,1); plot(x,g1,'-r','LineWidth',1.5); xlabel('t') title('Morlet 时域') g2=fft(g1); g3=abs(g2); subplot(2,2,2);...title('Morlet 频域')
  • 小波

    千次阅读 2014-10-29 09:29:51
    申明,本文非笔者原创,原文转载自:http://www.blogbus.com/shijuanfeng-logs/221293135.html
  • 代码:小波包分解与重构、小波包能量特征提取

    万次阅读 多人点赞 2018-06-29 11:22:23
    1、小波变换的理解 傅里叶变换——短时傅里叶变换——小波变换。 参考文献:以下两篇参考资料讲述得十分清楚,有助于理解小波变换。 但具体的数学角度阐述,请参考其他资料。 (1)知乎专栏:形象易懂讲解算法I——...
  • 说说wavedec2函数

    万次阅读 2016-01-05 09:39:45
    wavedec2函数: 1.功能:实现图像(即二维信号)的多层分解. 多层,即多尺度. 2.格式:[c,s]=wavedec2(X,N,'wname')  [c,s]=wavedec2(X,N,Lo_D,Hi_D)(我不讨论它) 3.参数说明:对图像X用w
  • Matlab小波工具箱的使用1

    千次阅读 2018-12-21 13:48:42
    Matlab小波工具箱的使用1  (2011-11-10 20:12:39) 转载▼ 标签:  小波分析   连续小波变换   尺度   系数   信号 分类: 学科知识 最近想尝试一下小波的用法,...
  • haar wavelet 塔式算法

    2020-07-30 23:32:40
    MATLAB中,采用塔式算法,标准haar小波和非标准haar小波,对一组随机生成数进行小波分解和重构。
  • function o= ls_inv_filter(w,wavelet,mu) %LS_INV_FILTER: Spiking deconvolution % % This program computes an inverse filter (Spiking filter) % from an estimate of a seismic wavelet. The actual % ...
  • 数字图像处理--小波变换MATLAB程序

    万次阅读 热门讨论 2018-08-20 08:28:14
    小波变换(wavelet transform,WT)是一种新的变换分析方法,它继承和发展了短时傅立叶变换局部化的思想,同时又克服了窗口大小不随频率变化等缺点,能够提供一个随频率改变的“时间-频率”窗口,是进行信号时频分析...
  • 这一步一般使用灰度共生矩阵,gabor wavelet等纹理分析方法,本文使用gabor小波在多个尺度上进行纹理分析。 舍弃纹理不显著的点(光滑区域)。 候选点选取 可以考察每个点与纹理信息的关系,计算每个点的得分,一般...
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