Measuring shape ellipticity

Abstract

A new ellipticity measure is proposed in this paper. The acquired shape descriptor shows how much the shape considered differs from a perfect ellipse. It is invariant to scale, translation, rotation and it is robust to noise and distortions. The new ellipticity measure ranges over (0, 1] and gives 1 if and only if the measured shape is an ellipse. The proposed measure is theoretically well founded, implying that the behaviour of the new measure can be well understand and predicted to some extent, what is always an advantage when select the set of descriptors for a certain application. Several experiments are provided to illustrate the behaviour and performance of the new measure.