图像的局部熵

clear all;close all;clc;img=imread('lena.jpg');[m n]=size(img);w=3;    %模板半径imgn=zeros(m,n);for i=1+w:m-w    for j=1+w:n-w                Hist=zeros(1,256);        for p=i-w:i+w            for q=j-w:j+w                Hist(img(p,q)+1)=Hist(img(p,q)+1)+1;    %统计局部直方图            end        end        Hist=Hist/sum(Hist);        for k=1:256            if Hist(k)~=0               imgn(i,j)=imgn(i,j)+Hist(k)*log(1/Hist(k));  %局部熵            end        end        %{          p=sum(sum(img(i-w:i+2,j-w:j+w)));   %这里是按第一个公式写的        s=img(i-w:i+w,j-w:j+w)/p;        imgn(i,j)=-sum(sum(s.*log(s)));        %}    endendimshow(imgn,[])imgn=entropyfilt(img);         %系统的局部熵函数figure;imshow(imgn,[])