%霍夫检测

BW=imread('lexp_1_2.bmp');

BW=rgb2gray(BW);

thresh=[0.01,0.17];

sigma=2;%定义高斯参数

f = edge(double(BW),'canny',thresh,sigma);

figure(1),imshow(f,[]);

title('canny 边缘检测');

[H, theta, rho]= hough(f,'RhoResolution', 0.5);

%imshow(theta,rho,H,[],'notruesize'),axis on,axis normal

%xlabel('\theta'),ylabel('rho');

peak=houghpeaks(H,5);

hold on

lines=houghlines(f,theta,rho,peak);

figure,imshow(f,[]),title('Hough Transform Detect Result'),hold on

for k=1:length(lines)

xy=[lines(k).point1;lines(k).point2];

plot(xy(:,1),xy(:,2),'LineWidth',4,'Color',[.6 .6 .6]);

end

%%

I=imread('1.jpg');

Ihsv=rgb2hsv(I);

Iv=Ihsv(:,:,3);                    %提取v空间

Ivl=Iv(500:end,:);              %截取下半部

Iedge=edge(Ivl,'sobel');    %边沿检测

Iedge = imdilate(Iedge,ones(3));%图像膨胀

%新建窗口，绘图用

figure (2)

imshow(Iedge);

hold on

%左方直线检测与绘制

%得到霍夫空间

[H1,T1,R1] = hough(Iedge,'Theta',20:0.1:75);

%求极值点

Peaks=houghpeaks(H1,5);

%得到线段信息

lines=houghlines(Iedge,T1,R1,Peaks);

%绘制线段

for k=1:length(lines)

xy=[lines(k).point1;lines(k).point2];

plot(xy(:,1),xy(:,2),'LineWidth',4);

end

%右方直线检测与绘制

[H2,T2,R2] = hough(Iedge,'Theta',-75:0.1:-20);

Peaks1=houghpeaks(H2,5);

lines1=houghlines(Iedge,T2,R2,Peaks1);

for k=1:length(lines1)

xy1=[lines1(k).point1;lines1(k).point2];

plot(xy1(:,1),xy1(:,2),'LineWidth',4);

end

hold off

%%

%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