Direct Ellipse Fitting and Measuring Based on Shape Boundaries

: Measuring ellipticity is an important area of computer vision systems. Most existing ellipticity measures are area based and cannot be easily applied to point sets such as extracted edges from real world images. We are interested in ellipse fitting and ellipticity measures which rely exclusively on shape boundary points which are practical in computer vision. They should also be calculated very quickly, be invariant to rotation, scaling and translation. Direct ellipse fitting methods are guaranteed to specifically return an ellipse as the fit rather than any conic. We argue that the only existing direct ellipse fit method does not work properly and propose a new simple scheme. It will determine the optimal location of the foci of the fitted ellipse along the orientation line (symmetrically with respect to the shape center) such that it minimizes the variance of sums of distances of points to the foci. We next propose a novel way of measuring the accuracy of ellipse fits against the o...

• Type: Conference
• Year: 2007
• Where: PSIVT
• Authors: Milos Stojmenovic, Amiya Nayak
• Keywords: Ellipse, Ellipse Fit, Ellipticity Measure, PSIVT 2007