HOUGH变换MATLAB

I = imread('D:\\My Documents\\MATLAB\\4.bmp');

figure,imshow(I),hold on;%show the original image title('The original imaage.');

rotI = rgb2gray(I); % convert to intensity image BW = edge(rotI,'canny'); % extract edges

[H,T,R] = hough(BW,'RhoResolution',0.5,'ThetaResolution',0.5);%hough transfer

figure,imshow(H,[],'XData',T,'YData',R,'InitialMagnification','fit'),hold on;

xlabel('\\theta'), ylabel('\\rho'); axis on, axis normal,hold on;

P = houghpeaks(H,10,'threshold',ceil(0.3*max(H(:)))); x = T(P(:,2)); y = R(P(:,1)); plot(x,y,'s','color','white'); % Find lines and plot them

lines = houghlines(BW,T,R,P,'FillGap',5,'MinLength',7); figure, imshow(rotI), hold on;

title('The lines that have been found'); max_len = 0;

for k = 1:length(lines)

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

plot(xy(:,1),xy(:,2),'LineWidth',2,'Color','red');

%Plot beginnings and ends of lines

%plot(xy(1,1),xy(1,2),'x','LineWidth',1,'Color','yellow'); %plot(xy(2,1),xy(2,2),'x','LineWidth',1,'Color','red');

% Determine the endpoints of the longest line segment len = norm(lines(k).point1 - lines(k).point2); if ( len > max_len) max_len = len; xy_long = xy; end end

% highlight the longest line segment

%plot(xy_long(:,1),xy_long(:,2),'LineWidth',1,'Color','cyan');