How do I convert a race track image file into X,Y coordinates?

After importing a race track image into MATLAB, I need to convert the image into a set of X,Y coordinates for lap simulation.

Answer 1

[Walter Roberson]

Probably: threshold and find(). Or perhaps threshold and one of the two boundary tracing routines.

Answer 2

[Christoph Hahn]

Hi Nikhil,

please consider uploading an image to be able to provide better support.

Assuming that you are working with binary images (binary -> black-white; if not, please consider converting) that may be a quite straightforward task. I suggest you have a look into the function list of image processing toolbox. What about 'edge'- and 'bwboundaries'-function.

Again, please consider providing an actual image to allow for better support.

Cheers Christoph

[saud khan]

What about this one? Please guide us to convert these type of images into X-Y coordinates.

[david kardam]

Please answer this question anyone

[Walter Roberson]

filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/257733/monza-graphic.jpeg';
rgb = imread(filename);
Red = rgb(:,:,1); Green = rgb(:,:,2); Blue = rgb(:,:,3);
bw = Blue > 150 & Red < 128;
imshow(rgb)

B = bwboundaries(bw);
plot(B{1}(:,2), B{1}(:,1), B{2}(:,2), B{2}(:,1), B{3}(:,2), B{3}(:,1))
set(gca, 'YDir', 'reverse')

Now B{1} is the Y and X coordinates around the outside of the racetrack.

B{2} is the Y and X coordinates around the inside of the racetrack.

B{3} is the Y and X coordinates of the outer edge of the island near the checkered flag.

[Demi Milet]

Can u maybe explain this code? im trying to use this for an image of a track of my own, but i get an error.

[Walter Roberson]

What error do you get? You would get an error in the plot in trying to use B{3} if you do not have something equivalent to the small island at the bottom right where the checkered flag is.