www.pudn.com > digitalimageprocessprograms.rar > ruihua.m

clc; 
fid=fopen('d:/img/lena.img','r'); 
f=fread(fid,[256,256],'uchar'); 
subplot(3,1,1); 
imshow(f,[0,255]); 
g1=f;g2=f; 
a=1; 
for x=2:255 
    for y=2:255 
        g1(x,y)=f(x,y)-(f((x-1),y)+f((x+1),y)+f(x,(y-1))+f(x,(y+1))-f(x,y).*4).*a; 
        g2(x,y)=f(x,y).*4*a-(f((x-1),y)+f((x+1),y)+f(x,(y-1))+f(x,(y+1))).*a; 
    end 
end 
subplot(3,1,2); 
imshow(g1,[0,255]); 
subplot(3,1,3); 
imshow(g2,[0,255]);