Search for line passing through a point in edge image

Hi all

I have an color image and I converted it to gray image then I do edge detection using 'canny'. The edge image contains horizontal, vertical and inclined lines. For specific pixel (xp,yp) in the edge image, I want to search for a vertical line that pass through this point.

Can anyone help me to find to a method to search or detect a vertical line passing in this point. Your help is highly appreciated.

I started with:

I=imread('image.jpg');

G=rgb2gray(I);

B=edge(G,'canny');

[Image Analyst]

Where did you post your image? http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers Post both your original image and the Canny edge image. Tell us the pixel (xp,yp) you're looking at, or let us know if you want to do that for every pixel in the image.

[Mary]

Hi Image Analyst and thank you for your comment.

I tried many times to upload the images to the forum , but I couldn't. could you please tell me the steps and the location that I can upload my images. I highly appreciate your help.

[Jan]

@Mary: Image Analyst had posted a link to the page, where you can upload images. Then post the link inside < and > or even better in << and &gt&gt. Please explain any details of "I cuoldn't" to allow us to suggest an improvement.

Answer 1

[ChristianW]

doc hough

[Mary]

Hi Christian and thank you for your answer

I read about Hough transform and I found these functions but I could't write the codes or the program to solve the problem. could you please help me for more details or a part of program. your help is greatly appreciated:

[H, theta, rho] = hough(BW)

[H, theta, rho] = hough(BW, ParameterName, ParameterValue)

peaks = houghpeaks(H, numpeaks)

peaks = houghpeaks(..., param1, val1, param2, val2)

lines = houghlines(BW, theta, rho, peaks)

lines = houghlines(..., param1, val1, param2, val2)

[ChristianW]

BW = diag(ones(1,100)); BW(:,[20 60])=1; BW(20:90,75)=1;

[H,T,R] = hough(BW);
P = houghpeaks(H,200);
It = T(P(:,2)) == 0; % index vector for theta == 0
lines = houghlines(BW,T,R,P(It,:));

isvline = false(size(BW));
for k = 1:length(lines)
   y = lines(k).point1(2) : lines(k).point2(2);
   x = lines(k).point1(1) * ones(size(y));
   isvline(y,x) = true;
end

isvline(38,75) % test, is pixel(yp=38,xp=75) part of a vertical line?

[Mary]

Thank you Christian for your answer.