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我按照该操作,下载了原程序,“上google,输入关键字emd.m,点击第一个链接,这是flandrin的一个关于EMD和HHT的网页,进入后就可以看见主要的几个m文件,对只搞EMD的朋友这些程序就够用了,如果要进行HHT后续分析,则需要点击Time-Frequency ToolBox链接下载工具箱,具体位置在Time-Frequency ToolBox页面的download处,下载后得到tftb-0.1.tar.gz压缩包,压缩包中有个mfiles文件夹,所有程序就齐全了。” 下边是就下载的emd程序的开始部分,开始输入的参数特别多(x,t,sd,sd2,tol,display_sifting,sdt,sd2t,ner,nzr,lx,r,imf,k,nbit,NbIt,MAXITERATIONS,FIXE,FIXE_H,MAXMODES,INTERP,mask),求教大家这些参数该怎么设置?另外,Hilbert变换后边的hhspectrum.m和instfreq.m程序怎么用呀?
% EMD.M
%
% G. Rilling, last update: May 2005
%
% computes EMD (Empirical Mode Decomposition) according to:
%
% N. E. Huang et al., "The empirical mode decomposition and the
% Hilbert spectrum for non-linear and non stationary time series analysis",
% Proc. Royal Soc. London A, Vol. 454, pp. 903-995, 1998
%
% with variations reported in:
%
% G. Rilling, P. Flandrin and P. Gon峚lv弒
% "On Empirical Mode Decomposition and its algorithms",
% IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing
% NSIP-03, Grado (I), June 2003
%
% default stopping criterion for sifting :
% at each point : mean amplitude < threshold2*envelope amplitude
% &
% mean of boolean array ((mean amplitude)/(envelope amplitude) > threshold) < tolerance
% &
% |#zeros-#extrema|<=1
%
% inputs:
% - x: analysed signal (line vector)
% - opts (optional): struct object with (optional) fields:
% - t: sampling times (line vector) (default: 1:length(x))
% - stop: threshold, threshold2 and tolerance (optional)
% for sifting stopping criterion
% default: [0.05,0.5,0.05]
% - display: if equals to 1 shows sifting steps with pause
% if equals to 2 shows sifting steps without pause (movie style)
% - maxiterations: maximum number of sifting steps for the computation of each mode
% - fix (int): disable the stopping criterion and do exactly
% the value of the field number of sifting steps for each mode
% - maxmodes: maximum number of imfs extracted
% - interp: interpolation scheme: 'linear', 'cubic' or 'spline' (default)
% - fix_h (int): do <fix_h> sifting iterations with |#zeros-#extrema|<=1 to stop
% according to N. E. Huang et al., "A confidence limit for the Empirical Mode
% Decomposition and Hilbert spectral analysis",
% Proc. Royal Soc. London A, Vol. 459, pp. 2317-2345, 2003
% - mask: masking signal used to improve the decomposition
% according to R. Deering and J. F. Kaiser, "The use of a masking signal to
% improve empirical mode decomposition",
% ICASSP 2005
%
% outputs:
% - imf: intrinsic mode functions (last line = residual)
% - ort: index of orthogonality
% - nbits: number of iterations for each mode
%
% calls:
% - io: computes the index of orthogonality
%
%examples:
%
%>>x = rand(1,512);
%
%>>imf = emd(x);
%
%>>imf = emd(x,struct('stop',[0.1,0.5,0.05],'maxiterations',100));
%Remark: the following syntax is equivalent
%>>imf = emd(x,'stop',[0.1,0.5,0.05],'maxiterations',100);
%
%>>options.dislpay = 1;
%>>options.fix = 10;
%>>options.maxmodes = 3;
%>>[imf,ort,nbits] = emd(x,options);
function [imf,ort,nbits] = emd(varargin);
[x,t,sd,sd2,tol,display_sifting,sdt,sd2t,ner,nzr,lx,r,imf,k,nbit,NbIt,MAXITERATIONS,FIXE,FIXE_H,MAXMODES,INTERP,mask] = init(varargin{:});
if display_sifting
figure
end
[ 本帖最后由 zhangnan3509 于 2007-7-4 14:50 编辑 ] |
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