eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld (Operator)

Name

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

Signature

eccentricity_points_xld(XLD : : : Anisometry)

Description

The operator eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXldEccentricityPointsXld calculates the shape feature AnisometryAnisometryAnisometryAnisometryanisometry derived from the geometric moments of the point cloud given by the contour or polygon XLDXLDXLDXLDXLD (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_xldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXldEllipticAxisPointsXld) are given, the following applies: The anisometry of a circle is 1.0.

eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXldEccentricityPointsXld should be used if the contour XLDXLDXLDXLDXLD 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_xldEccentricityXldEccentricityXldEccentricityXld does not produce useful results. To test whether the contours or polygons intersect themselves, test_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXldTestSelfIntersectionXld 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 XLDXLDXLDXLDXLD.

Execution Information

Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
Automatically parallelized on tuple level.

Parameters

XLDXLDXLDXLDXLD (input_object) xld(-array) → object

Contours or polygons to be examined.

AnisometryAnisometryAnisometryAnisometryanisometry (output_control) real(-array) → (real)

Anisometry of the contours or polygons.

Assertion: Anisometry >= 1.0

Result

The operator eccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXldEccentricityPointsXld 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>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary an exception is raised.