两个matlab实现最大熵法图像分割程序.doc
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%两个程序,亲测可用
clearall
a=imread('moon.tif');
figure,imshow(a)
count=imhist(a);
[m,n]=size(a);
N=m*n;
L=256;
count=count/N;%%每一个像素的分布概率
count
fori=1:
L
ifcount(i)~=0
st=i-1;
break;
end
end
st
fori=L:
-1:
1
ifcount(i)~=0
nd=i-1;
break;
end
end
nd
f=count(st+1:
nd+1);%f是每个灰度出现的概率
size(f)
E=[];
forTh=st:
nd-1%%%设定初始分割阈值为Th
av1=0;
av2=0;
Pth=sum(count(1:
Th+1));
%%%第一类的平均相对熵为
fori=0:
Th
av1=av1-count(i+1)/Pth*log(count(i+1)/Pth+0.00001);
end
%%%第二类的平均相对熵为
fori=Th+1:
L-1
av2=av2-count(i+1)/(1-Pth)*log(count(i+1)/(1-Pth)+0.00001);
end
E(Th-st+1)=av1+av2;
end
position=find(E==(max(E)));
th=st+position-1
fori=1:
m
forj=1:
n
ifa(i,j)>th
a(i,j)=255;
else
a(i,j)=0;
end
end
end
figure,imshow(a);
%%%%%%%%%%%%%%%%%%%%%2-d最大熵法(递推方法)%%%%%%%%%%%
clearall;
clc;
tic
a=imread('trial2_2.tiff');
figure,imshow(a);
a0=double(a);
[m,n]=size(a);
h=1;
a1=zeros(m,n);
%计算平均领域灰度的一维灰度直方图
fori=1:
m
forj=1:
n
fork=-h:
h
forw=-h:
h;
p=i+k;
q=j+w;
if(p<=0)|(p>m)
p=i;
end
if(q<=0)|(q>n)
q=j;
end
a1(i,j)=a0(p,q)+a1(i,j);
end
end
a2(i,j)=uint8(1/9*a1(i,j));
end
end
fxy=zeros(256,256);
%计算二维直方图
fori=1:
m
forj=1:
n
c1=a0(i,j);
d=double(a2(i,j));
fxy(c1+1,d+1)=fxy(c1+1,d+1)+1;
end
end
Pxy=fxy/m/n;
%figure,
%mesh(Pxy);
%title('二维灰度直方图');
%计算Hl
Hl=0;
fori=1:
256
forj=1:
256
ifPxy(i,j)>0.00001
Hl=Hl-Pxy(i,j)*log(Pxy(i,j));
else
Hl=Hl;
end
end
end
%计算PA,HA
PA=zeros(256,256);
HA=zeros(256,256);
PB=zeros(256,256);
PA(1,1)=Pxy(1,1);
ifPA(1,1)<1e-4
HA(1,1)=0;
else
HA(1,1)=-PA(1,1)*log(PA(1,1));
end
fori=2:
256
PA(i,1)=PA(i-1,1)+Pxy(i,1);
ifPxy(i,1)>0.00001
HA(i,1)=HA(i-1,1)-Pxy(i,1)*log(Pxy(i,1));
else
HA(i,1)=HA(i-1,1);
end
end
forj=2:
256
PA(1,j)=PA(1,j-1)+Pxy(1,j);
ifPxy(1,j)>0.00001
HA(1,j)=HA(1,j-1)-Pxy(1,j)*log(Pxy(1,j));
else
HA(1,j)=HA(1,j-1);
end
end
fori=2:
256
forj=2:
256
PA(i,j)=PA(i-1,j)+PA(i,j-1)-PA(i-1,j-1)+Pxy(i,j);
ifPxy(i,j)>0.00001
HA(i,j)=HA(i-1,j)+HA(i,j-1)-HA(i-1,j-1)-Pxy(i,j)*log(Pxy(i,j));
else
HA(i,j)=HA(i-1,j)+HA(i,j-1)-HA(i-1,j-1);
end
end
end
%计算最大熵
PB=1-PA;
h=zeros(256,256);
hmax=0;
fori=1:
256
forj=1:
256
ifabs(PA(i,j))>0.00001&abs(PB(i,j))>0.00001
h(i,j)=log(PA(i,j)*PB(i,j))+HA(i,j)/PA(i,j)+(Hl-HA(i,j))/PB(i,j);
else
h(i,j)=0;
end
ifh(i,j)>hmax
hmax=h(i,j);
s=i-1;
t=j-1;
end
end
end
z=ones(m,n);
fori=1:
m
forj=1:
n
ifa0(i,j)<=s&a2(i,j)<=t
%ifdouble(a(i,j))+double(a2(i,j))+a3(i,j)<=s+t+q
z(i,j)=0;
else
z(i,j)=255;
end
end
end
hmax
s
t
figure,imshow(z);
toc