a=imread('C:\Documents and Settings\Administrator\桌面\bbb.bmp');
a=rgb2gray(a);
figure
imshow(a)
d=a>190;
figure
imshow(d)
b1=bwperim(d);
figure
imshow(b1)
h=0;
l=0;
n=0;
for i=224:278
     for j=268:278
        if b1(i,j)==1
             h=h+i;
             l=l+j;
             n=n+1;
         end
     end
end
 h=h/n;
 l=l/n;
 disp([h,l]);