Ellipse Detection using the Hough Transform

We consider the problem of detecting elliptical curves using Hough Transform methods. Storage and efficiency problems are overcome by decomposing the problem into two stages. The first stage uses a novel constraint as the basis for a Hough Transform to detect the ellipse center while the second stage finds the remaining parameters using a simple but efficient focussing implementation of the HT. The method is applicable in many situations where previous HT schemes would fail. Results are demonstrated for complex image data containing several overlapping and occluding ellipses.