1 cl;
 2 m=31;
 3 n=31;
 4 img=zeros(m+1,n+1);
 5 img=double(img);
 6 pi=3.1415926;
 7 sigma=10;
 8 for i=-(m/2):m/2
 9     for j=-(n/2):n/2
10         img(i+m/2+1,j+n/2+1)=(1/(2*pi*sigma*sigma))*exp(-(i*i+j*j)/(2*sigma*sigma)); 
11     end
12 end
13 img=mat2gray(img);
14 imshow(img);
15 imwrite(img,'pic.bmp');
16 
17 %一个更好的实现，2012.12.18修改
18 h=5;
19 w=2;
20 [x y]=meshgrid(-w:w,-h:h);
21 sigma=5;
22 img = (1/(2*pi*sigma^2))*exp(-(x.^2+y.^2)/(2*sigma^2));