Masao Hiyane

A circle-detection algorithm simulating wave propagation

Based on the analogy of the Hough transform and Huygenss principle, we present a circle-detection algorithm that numerically solves a two-dimensional wave equation using neighbor-based operations only, that is, Laplacian, frame addition, and multiplication of constants with frame contents, all basic functions of standard image processors. Because it does not use edge extraction, the algorithm detects circles even from low-contrast and blurred images. A comparison of point spread functions shows the algorithm to be equivalent to the weighted Hough transform but requiring much less computation. We applied the algorithm to disk-surface inspection of low-contrast and blurred microscopic images.