# reference: http://aishack.in/tutorials/hough-transform-basics/
# reference: http://aishack.in/tutorials/hough-transform-normal/
# reference: https://alyssaq.github.io/2014/understanding-hough-transform/
# reference: https://github.com/alyssaq/hough_transform
# reference: https://github.com/vmonaco/general-hough/blob/master/src/GeneralHough.py

