The paper introduces a novel confocal ellipse-based distance (CED), that is based on the properties of the confocal ellipses. This distance is used to produce a confocal elliptical field (CEF). The Euclidean Distance Transform (EDT) of a single point (called seed) generates a distance field of concentric circles. The sum of two such distance fields of two distinct seed points produces a distance field of confocal ellipses. This fact enables to adapt CED and CEF to the discrete case, referred to as CED­DT and CEF-DT. The properties of the CEF and CEF-DT make them useful for skeletonization, in particular for efficient removal of the spurious branches.


Gabdulkhakova, A., & Kropatsch, W. (2018). Confocal Ellipse-based Distance and Confocal Elliptical Field for Polygonal Shapes. In IAPR/ICPR 2018 International Conference on Pattern Recognition (pp. 3025–3030). IEEE Computer Society. http://hdl.handle.net/20.500.12708/57535