emd_EMD_EMD分解

function imf = emd1(x) % Empiricial Mode Decomposition (Hilbert-Huang Transform) % EMD分解或HHT变换 % 返回值为cell类型，依次为一次IMF、二次IMF、...、最后残差 x = transpose(x(:)); imf = []; while ~ismonotonic(x) x1 = x; sd = Inf; while (sd > 0.1) || ~isimf(x1) s1 = getspline(x1); % 极大值点样条曲线 s2 = -getspline(-x1); % 极小值点样条曲线 x2 = x1-(s1+s2)/2; sd = sum((x1-x2).^2)/sum(x1.^2); x1 = x2; end imf{end+1} = x1; x = x-x1; end imf{end+1} = x; % 是否单调 function u = ismonotonic(x) u1 = length(findpeaks(x))*length(findpeaks(-x)); if u1 > 0 u = 0; else u = 1; end % 是否IMF分量 function u = isimf(x) N = length(x); u1 = sum(x(1:N-1).*x(2:N) < 0); % 过零点的个数 u2 = length(findpeaks(x))+length(findpeaks(-x)); % 极值点的个数 if abs(u1-u2) > 1 u = 0; else u = 1; end % 据极大值点构造样条曲线 function s = getspline(x) N = length(x); p = findpeaks(x); s = spline([0 p N+1],[0 x(p) 0],1:N);