eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld (Operator)

Name

eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld — Anisometry of contours or polygons treated as point clouds.

Signature

eccentricity_points_xld(XLD : : : Anisometry)

The operator eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld calculates the shape feature AnisometryAnisometryAnisometryAnisometryAnisometryanisometry derived from the geometric moments of the point cloud given by the contour or polygon XLDXLDXLDXLDXLDXLD (i.e., the order of the points in the contour or polygon is not taken into account). If the contour or polygon is closed (end point = start point), the end point of the contour or polygon is not taken into account to avoid that it receives twice the weight of the other points.

Calculation:

            If the ellipse radii Ra, Rb
            (see elliptic_axis_points_xldelliptic_axis_points_xldEllipticAxisPointsXldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXld)
            are given,
            the following applies:

            AnisometryAnisometryAnisometryAnisometryAnisometryanisometry = Ra / Rb

The anisometry of a circle is 1.0.

eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld should be used if the contour XLDXLDXLDXLDXLDXLD intersects itself or if it is not possible to close the contour using a line from end to start point without self-intersection, because in this case eccentricity_xldeccentricity_xldEccentricityXldeccentricity_xldEccentricityXldEccentricityXld does not produce useful results. To test whether the contours or polygons intersect themselves, test_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld can be used.

If more than one contour or polygon is passed, the values of the anisometry are stored in a tuple in the same order as the respective contours or polygons in XLDXLDXLDXLDXLDXLD.