clear all;
close all;
clc;


%%
%以下只是做一个带直线的图像而已
r=300;           
jiaodu=30;      %更改这个值测试，90度270度时不管用
jiaodu1=mod(jiaodu,360);     
flag=0;

if jiaodu1>=0 && jiaodu1<90
    jiaodu1=jiaodu1;
    flag=1;
end

if jiaodu1>=90 && jiaodu1<180
    jiaodu1=180-jiaodu1;
    flag=2;
end

if jiaodu1>=180 && jiaodu1<270
    jiaodu1=jiaodu1-180;
    flag=3;
end

if jiaodu1>=270 && jiaodu1<360
    jiaodu1=360-jiaodu1;
    flag=4;
end

H=floor(r*sin(jiaodu1*pi/180));
W=floor(r*cos(jiaodu1*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 jiaodu1 ~= 90 && jiaodu1 ~= 270
    for i=1:H
        for j=1:W
            tmp=floor(j*tan(jiaodu1*pi/180));
            if tmp+1==i
                w(i,j)=r;
            end
        end
    end
else
    for i=1:H
        w(i,1)=r;
    end
end
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
%%
%下面是真正的霍夫变换
img=mat2gray(w);      %处理这个图像
[m n]=size(img);
imshow(img);

data=zeros(314,2*(m+n));
for i=1:m                       %将图像二维空间的一个点映射到p=x*cos(theta)+y*sin(theta)方程对应的参数空间的一条曲线
    for j=1:n
        if img(i,j)==1            
            for theta=0.01:0.01:3.14
                data(round(theta*100),round(i*sin(theta)+j*cos(theta)+m+n))= ...
                data(round(theta*100),round(i*sin(theta)+j*cos(theta)+m+n))+1;
            end        
        end
    end
end

theta=0;
ma=0;
for i=1:314                 %寻找曲线相交最多的那个点，即找最大值
    for j=1:2*(m+n)
        if data(i,j)>ma
            ma=data(i,j);
            theta=i/100;
            rou=j-m-n;
        end
    end
end
figure;imshow(data)     %形象的显示参数空间曲线

sr_k=tan(jiaodu*pi/180)     %设置的斜率
re_k=cos(theta)/sin(theta)  %求得的斜率