The following code was writen in Matlab to detect multiple disks in an image using the HT.
Steps:
1. Turn the colored image into grayscale
2. Create a 3D Hough array (accumulator) with the first two dimensions representing the
coordinates of the circle origin and the third dimension represents the radii
3. Detect edges using the Canny edge detector. For each edge pixel (point), increment the
corresponding elements in the Hough array.
4. Collect candidate circles, then delete similar circles.
5. Draw circles around coins.