Hough transform algorithm
	Typically use a different parameterization • d is the perpendicular distance from the line to the origin • q is the angle this perpendicular makes with the x axis • Why? Basic Hough transform algorithm 1. Initialize H[d, q]=0 2. for each edge point I[x,y] in the image     for q = 0 to 180     H[d, q] += 1 3. Find the value(s) of (d, q) where H[d, q] is maximum 4. The detected line in the image is given by What’s the running time (measured in # votes)?
		•    O(edge pixels * line directions)			Hough line demo