eccentricity_xldeccentricity_xldeccentricity_xldEccentricityXldEccentricityXld (Operator)

Name

eccentricity_xldeccentricity_xldeccentricity_xldEccentricityXldEccentricityXld — Shape features derived from the ellipse parameters of contours or polygons.

Signature

Description

The operator eccentricity_xldeccentricity_xldeccentricity_xldEccentricityXldEccentricityXld calculates the three shape features AnisometryAnisometryAnisometryAnisometryanisometry, BulkinessBulkinessBulkinessBulkinessbulkiness, and StructureFactorStructureFactorStructureFactorStructureFactorstructureFactor derived from the geometric moments for each input contour or polygon. If the input contour or polygon is not closed it will be closed automatically.

Calculation:

   If the ellipse radii Ra, Rb (see elliptic_axis_xldelliptic_axis_xldelliptic_axis_xldEllipticAxisXldEllipticAxisXld)
   and the enclosed area A of the contour or polygon are given,
   the following applies:

   AnisometryAnisometryAnisometryAnisometryanisometry = Ra / Rb

   BulkinessBulkinessBulkinessBulkinessbulkiness = pi Ra Rb / A

   StructureFactorStructureFactorStructureFactorStructureFactorstructureFactor = AnisometryAnisometryAnisometryAnisometryanisometry * BulkinessBulkinessBulkinessBulkinessbulkiness - 1

The anisometry of a circle is 1.0.

It should be noted that eccentricity_xldeccentricity_xldeccentricity_xldEccentricityXldEccentricityXld only returns useful results if the contour or polygon encloses a region in the plane. In particular, the contour or polygon must not intersect itself. This is particularly important if open contours or polygons are passed because they are closed automatically, which can produce a self-intersection. To test whether the contours or polygons intersect themselves, test_self_intersection_xldtest_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld can be used. If the contour or polygon intersects itself, a useful value for the anisometry can be calculated with eccentricity_points_xldeccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld.

If more than one contour is passed the results are stored in tuples, the index of a value in the tuple corresponding to the index of a contour in the input.

Parallelization

• 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

Result

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

Possible Predecessors

gen_contours_skeleton_xldgen_contours_skeleton_xldgen_contours_skeleton_xldGenContoursSkeletonXldGenContoursSkeletonXld, edges_sub_pixedges_sub_pixedges_sub_pixEdgesSubPixEdgesSubPix, threshold_sub_pixthreshold_sub_pixthreshold_sub_pixThresholdSubPixThresholdSubPix, gen_contour_polygon_xldgen_contour_polygon_xldgen_contour_polygon_xldGenContourPolygonXldGenContourPolygonXld, test_self_intersection_xldtest_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld

Alternatives

eccentricity_points_xldeccentricity_points_xldeccentricity_points_xldEccentricityPointsXldEccentricityPointsXld

See also

elliptic_axis_xldelliptic_axis_xldelliptic_axis_xldEllipticAxisXldEllipticAxisXld, moments_region_2ndmoments_region_2ndmoments_region_2ndMomentsRegion2ndMomentsRegion2nd, select_shape_xldselect_shape_xldselect_shape_xldSelectShapeXldSelectShapeXld, area_center_xldarea_center_xldarea_center_xldAreaCenterXldAreaCenterXld

Module

Foundation