A Parallel Hardware and Associated Algorithms for Fast Detection of Circles and Symmetric Patterns

Abstract

A VLSI array processor, consisting of two sets of data-shifters and an array of AND-gates, is proposed to implement the hardwired midpoint finding and to support the fast locating of possible symmetric axes of image patterns. By further analyzing the line segments formed by these midpoints, the radii and centers of circles in the image can be found. The circuit of this design is simple and the operation is efficient. This detection scheme can be extended to the more general cases of ellipses and patterns with vertical (or horizontal) symmetric axis.