1. A method of detecting elliptical structures in an image, the method comprising the steps of: detecting circular arc-shaped structures in the image by means of a circle Hough transform (CHT) of the image, wherein a radius and a center point are determined for each circular arc-shaped structure, identifying pairs of circular arc-shaped structures consisting of two of the detected circular arc-shaped structures with substantially equal radii, defining, for each of the pairs of circular arc-shaped structures, a search area within the image depending on the center points of the respective pair of circular arc-shaped structures, searching, for each of the pairs of circular arc-shaped structures, in the search area defined for the pair of circular arc-shaped structures, for a pair of edges connecting the two circular arc-shaped structures of this pair of circular arc-shaped structures, identifying, if a pair of edges connecting the two circular arc-shaped structures of a pair of circular arc-shaped structures is found, an area enclosed by this pair of edges and this pair of circular arc-shaped structures as an elliptical structure.