eccentricity_points_xld — Anisometry of contours or polygons treated as point clouds.
The operator eccentricity_points_xld calculates the shape feature Anisometry derived from the geometric moments of the point cloud given by the contour or polygon XLD (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 (elliptic_axis_points_xld) are given, the following applies:
eccentricity_points_xld should be used if the contour XLD 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_xld does not produce useful results. To test whether the contours or polygons intersect themselves, test_self_intersection_xld 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 XLD.
Contours or polygons to be examined.
Anisometry of the contours or polygons.
Assertion: Anisometry >= 1.0
The operator eccentricity_points_xld returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input contours available) is set via the operator set_system('no_object_result',<Result>). If necessary an exception is raised.
gen_contours_skeleton_xld, edges_sub_pix, threshold_sub_pix, gen_contour_polygon_xld, test_self_intersection_xld
elliptic_axis_points_xld, moments_region_2nd, select_shape_xld