Polling an image for circles by random lines

A new random sampling strategy, designed for retrieving subsets consisting of two edge pixels from an input image, is proposed as the sampling process for RANSAC circle detection using coaxial transform. The proposed strategy is shown to have the following advantages over the conventional random sampling strategy. First, a poll size can be planned in a principled manner. Second, once a poll size is set, the probability that a circle is missed by the sampling process is kept relatively constant regardless of noise. Third, the actual number of subsets taken is automatically adjusted for different image complexities. Experimental results in agreement with the claimed advantages are presented.