基于双边滤波的图像处理，为什么会输出两个黑框？以下代码

Question

clear all;
close all;
clc;

img=imread('t_2.jpg');
img=mat2gray(img);
[m n]=size(img);
%imshow(img);

r=10; %模板半径
imgn=zeros(m+2*r+1,n+2*r+1);
img=imgn(r+1:m+r,r+1:n+r);
imgn(1:r,r+1:n+r)=img(1:r,1:n); %扩展上边界
imgn(1:m+r,n+r+1:n+2*r+1)=imgn(1:m+r,n:n+r); %扩展右边界
imgn(m+r+1:m+2*r+1,r+1:n+2*r+1)=imgn(m:m+r,r+1:n+2*r+1); %扩展下边界
imgn(1:m+2*r+1,1:r)=imgn(1:m+2*r+1,r+1:2*r); %扩展左边界

sigma_d=2;
sigma_r=0.1;
[x,y] = meshgrid(-r:r,-r:r);
w1=exp(-(x.^2+y.^2)/(2*sigma_d^2)); %以距离作为自变量高斯滤波器

h=waitbar(0,'wait...');
for i=r+1:m+r
for j=r+1:n+r

w2=exp(-(imgn(i-r:i+r,j-r:j+r)-imgn(i,j)).^2/(2*sigma_r^2)); %以周围和当前像素灰度差值作为自变量的高斯滤波器
w=w1.*w2;

    s=imgn(i-r:i+r,j-r:j+r).*w;
    imgn(i,j)=sum(sum(s))/sum(sum(w));

end
waitbar(i/m);

end
close(h)

figure;
imshow(mat2gray(imgn(r+1:m+r,r+1:n+r)));

Answer 1

http://blog.csdn.net/xw20084898/article/details/21822565