An Improved Circle Detection Method Based on Right Triangles Inscribed in a Circle

An efficient method of detecting circles, called semi- random detection (SRD) based on right triangles inscribed in a circle (RTIC), is presented. Above all, a 2D compressed array space based on the positions of valid pixels (ASPVP) is constructed. And then four points searching method is used to search the corresponding right triangles. After employing a few specific and effective tools such as radius constraint, error distance judgment, data merging etc., real circle check is applied to get the real circles. Some composite images with different levels of noises and some real images have been taken to test the performance. Experimental results show that the proposed algorithm is fast, reliable and spatially compact.