An Implementation Of The Hough Transform For Line And Circle Location
James F Boyce, G.A. Jones, V. F. Leavers · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1987
Maxima in Hough space which correspond to straight line segments have a characteristic 'butterfly' shape. The intensity of regions which correspond to circles have an inverse square root singularity at their edge. Filters are thereby designed which automatically extract line and circle parameters.