Abstract: A method and a system of object contours comparisons are described. A first tree structure that connects all points of a set of points is determined such that a length of the first tree structure is smaller than a length of any other possible tree structures for connecting all points. Based on the first tree structure, a first subset of the set of points is determined such that it includes points ordered to form a path that satisfies a selection criterion for representing a first contour of a first object. From the first subset of points and a second set of points that forms a contour of a second object, a set of points of interest is determined. The first object and the second object are compared based on characteristics of the shape indicative of a difference between the first and the second contours formed by the points of interest.