box_frac_dem.m

分形计算的几个程序原码

function fd=box_frac_dem(X); 
% 差分盒维数 
% Example: 
%    X=double(imread('rice.tif')); 
%    fd=box_frac_dem(X); 
% Author email of the program:% [e-mail] 
% 
% Reference: 
% Sarkar N,Chaudhuri B B. An efficient approach to estimate 
% fractal dimensionof textural images [J].Pattern Recognition, 
% 1992,25(9):1035-1041 

if size(X,1)~=size(X,2); 
   error('The size of X must NxN.'); 
end 
B=size(X,1); 
if mod(log2(B),1)>0; 
   error('The size of X must 2^n'); 
end 
t=log2(B); 
s=2.^(1:t); 
Nr=zeros(1,t); 
for k=1:t; 
   d=s(k); 
   h=256/d; % Let B instead of 256 for the size [2^nX2^n] 
   for m=1:h; 
       for n=1:h; 
           A=X(d*(m-1)+[1:d],d*(n-1)+[1:d]); 
           mn=min(A(1:end)); 
           mx=max(A(1:end)); 
           nr=fix(mx/d)-fix(mn/d)+1; 
           Nr(k)=Nr(k)+nr; 
       end 
   end 
end 
r=B./s; 
p=polyfit(log10(r),log10(Nr),1); 
fd=p(1);