evaluate.m

用来描述融合图像的熵值

function [stad_deviation,stad_variance,entropy] = evaluate(I)
%I为融合图像
%stad_deviation:融合图像的标准偏差
%variance：融合图像的标准方差
%entropy:融合图像的熵
%%
%求标准偏差
I1 = imread(I);
[sI,cI,bI] = size(I1);
t = 0.;h = 0.;
for i = 1:sI
    for j = 1:cI
        h = double(I1(i,j));
        t = t+h^2;
    end
end
stad_deviation = sqrt(double(t/(sI*cI-1)));
%%
%求方差
u =0.;
I2 = imread(I);
for i = 1:sI
    for j = 1:cI
       u = u+double(I2(i,j));      
    end
end
u = u/(sI*cI);
k = 0.;
for i = 1:sI
    for j = 1:cI
        y = double(I2(i,j));
        k = k+(y-u)^2;
    end
end
stad_variance = sqrt(double(k/(sI*cI)));

%%
%求图像的熵
I3 = imread(I);
I3 = double(I3)+1;
s(256) = 0;
for i = 1:sI
    for j = 1:cI
        va = I3(i,j);
        s(va) = s(va)+1;
    end
end
p = s./(sI*cI);
en = 0.;
for i = 1:256
    if p(i)~=0
       en = en+p(i)*log2(p(i));%概率取对数(以2为底)再乘以概率 最后连加取反
    end
end
entropy = -en;