学步园

cl;
img=imread('1.bmp');
[m n]=size(img);
imshow(img)
imgn=img;
temp=[];
%开操作
for i=2:m-1                 %腐蚀
for j=2:n-1
        temp=img(i-1:i+1,j-1:j+1);
        imgn(i,j)=min(temp(:));     
end
end

for i=2:m-1                %膨胀  
for j=2:n-1
        temp=img(i-1:i+1,j-1:j+1);
        imgn(i,j)=max(temp(:));     
end
end

figure,imshow(imgn);
img=double(img);
imgn=double(imgn);
imgn=img-imgn;
figure,imshow(mat2gray(imgn));