clear all;
close all;
clc;
r=50;           %模糊半径
jiaodu=-45;      %模糊角度
jiaodu=mod(jiaodu,360);     %经过这个处理，对所有角度均适用了。
flag=0;

%%下面是把卷积模板做出来。
if jiaodu>=0 && jiaodu<90
    jiaodu=jiaodu;
    flag=1;
end

if jiaodu>=90 && jiaodu<180
    jiaodu=180-jiaodu;
    flag=2;
end

if jiaodu>=180 && jiaodu<270
    jiaodu=jiaodu-180;
    flag=3;
end

if jiaodu>=270 && jiaodu<360
    jiaodu=360-jiaodu;
    flag=4;
end

H=floor(r*sin(jiaodu*pi/180));
W=floor(r*cos(jiaodu*pi/180));

if mod(H,2)==0
    H=H+1;
end

if mod(W,2)==0
    W=W+1;
end

w=zeros(H,W);
if jiaodu ~= 90 && jiaodu ~= 270
    for i=1:H
        for j=1:W
            tmp=floor(j*tan(jiaodu*pi/180));
            if tmp+1==i
                w(i,j)=r;
            end
        end
    end
else
    for i=1:H
        w(i,1)=r;
    end
end

w=w/sum(sum(w));
if flag==1 || flag==3       %如果角度在1,3象限，卷积矩阵上下翻转
    w=flipud(w);        
end

%%下面是正常的图像处理，卷积等
HH=floor(H/2);
WW=floor(W/2);

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

imgn=zeros(m+2*HH+1,n+2*WW+1);
imgn(HH+1:m+HH,WW+1:n+WW)=img;

imgn(1:HH,WW+1:n+WW)=img(1:HH,1:n); 
imgn(1:m+HH,n+WW+1:n+2*WW+1)=imgn(1:m+HH,n:n+WW);
imgn(m+HH+1:m+2*HH+1,WW+1:n+2*WW+1)=imgn(m:m+HH,WW+1:n+2*WW+1);
imgn(1:m+2*HH+1,1:WW)=imgn(1:m+2*HH+1,WW+1:2*WW);

for i=HH+1:m+HH
    for j=WW+1:n+WW        
        s=imgn(i-HH:i+HH,j-WW:j+WW).*w;
        imgn(i,j)=sum(sum(s))/sum(sum(w));    
    end
end

figure;
img=imgn(HH+1:m+HH,WW+1:n+WW);
imshow(mat2gray(img));