The Hough transform for circle detection requires the search of a 3-dimensional parameter space for circles of arbitrary radius. A technique has been developed which calculates intersection points of edge gradient vectors storing response weights in one plane and the product of weights and radii in another plane effectively eliminating the radius dimension of the parameter space. The result is a significant savings in both search time and storage in the parameter space accumulator. © 1988.
Conker, R. S. (1988). A dual plane variation of the Hough transform for detecting non-concentric circles of different radii. Computer Vision, Graphics and Image Processing, 43(2), 115–132. https://doi.org/10.1016/0734-189X(88)90057-6