variation.m

方差法计算分维数

%变换法计算分维数
clear
load z1024h3_4.mat%待分析数据
y=z(1:1024)

x=length(y)
n=4%初始窗口数量
time=5%窗口尺度变化次数

for t=1:time
    w=x/n%单个窗口的宽度
    S(t)=0
%     for ii=1:x-w
%         Winy=y(ii:ii+w)
    for ii=1:n
        Winy=y((ii-1)*w+1:ii*w)
        S(t)=(max(Winy)-min(Winy))*w+S(t)
    end
    N(t)=S(t)/(w^2)
    R(t)=1/w
    R2(t)=w
    n=n*2
end

% Nlog=log(S)
% Rlog=log(R2)
Nlog=log(N)
Rlog=log(R)
plot(Rlog,Nlog,'.')
grid on
hold on
P=polyfit(Rlog,Nlog,1)%最小二乘法拟合数据
xx=[floor(min(Rlog)):ceil(max(Rlog))]
yy=P(1)*xx+P(2)
plot(xx,yy)
D=P(1)
H=2-D