Hough(matlab)

clear
close all
clc
I= imread('111.jpg');% 读取图像
f =rgb2gray(I);
%二值化
f = im2bw(f,0.35);
f =255-f;
f = edge(f,'canny');
figure;imshow(f);
%获取霍夫空间
%  'RhoResolution', Hough 变换 bin 沿 rho 轴的间距
%  指定为介于 0 和 norm(size(BW))之间（不包含两者）的正数。没明白啥意思

% 'Theta',角度值 取值范围为-90~89
[H,T,R] = hough(f,'RhoResolution',0.01,'Theta',-1:0.01:1);
% R 与原点之间的距离值
% T 角度值
% H 霍夫值
figure;imagesc(R,T,H);colormap(hot);colorbar
xlabel('\theta T'), ylabel('\rho R');
axis on, axis normal, hold on;

% 对h值进行筛选
[m,n] = find(H<95 & H>70);
%获取筛选后在霍夫空间的分布
t = T(n(:,1));
r = R(m(:,1));
% 创建空白图用于绘制
figure;
[m1,n1] = size(f);
z = zeros(m1,n1);
% imshow(z,[]);
%显示原图，将直线绘在原图上
imshow(f,[]);
% 霍夫空间逆变换
for i=1:size(t,2)
    y(i,1) = (r(i)- 1*cos((t(i)+360)*(pi/180)))/sin((t(i)+360)*(pi/180));
    y(i,2) = (r(i)- size(f(1,:),2)*cos((t(i)+360)*(pi/180)))/sin((t(i)+360)*(pi/180));
    xy(1,1) =1;
    xy(2,1) =y(i,1);
    xy(1,2) =size(f(1,:),2);
    xy(2,2) =y(i,2);
    hold on
    plot(xy(1,:),xy(2,:),'LineWidth',1,'Color','red');
end