emd分解

%此版本為ALAN 版本的整合注釋版 
 function imf = emd(x)
 % Empiricial Mode Decomposition (Hilbert-Huang Transform)
 % imf = emd(x)
 % Func : findpeaksx= transpose(x(:));%轉置為行矩陣
 imf = [];while ~ismonotonic(x) %當x不是單調函數，分解終止條件
    x1 = x;
    sd = Inf;%均值
 %直到x1滿足IMF條件，得c1
    while (sd > 0.1) | ~isimf(x1) %當标準偏差系數sd大于0.1或x1不是固有模态函數時，分量終止條件
       s1 = getspline(x1);%上包絡線
       s2 = -getspline(-x1);%下包絡線
       x2 = x1-(s1+s2)/2;%此處的x2為文章中的h
       
       sd = sum((x1-x2).^2)/sum(x1.^2);
       x1 = x2;
    end
    
    imf{end+1} = x1;
    x          = x-x1;
 endimf{end+1} = x;