circularity_xldcircularity_xldcircularity_xldCircularityXldCircularityXld (Operator)

Name

circularity_xldcircularity_xldcircularity_xldCircularityXldCircularityXld — Shape factor for the circularity (similarity to a circle) of contours or polygons.

Signature

Description

The operator circularity_xldcircularity_xldcircularity_xldCircularityXldCircularityXld calculates the similarity of each input contour or polygon with a circle. The input contour or polygon must not intersect itself, otherwise the resulting parameter is not meaningful (Whether the input contour or polygon intersects itself or not can be determined with test_self_intersection_xldtest_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld). If the input contour or polygon is not closed it will be closed automatically.

Calculation:

If F is the area enclosed by the contour or polygon and max is the
maximum distance from the center to all contour or polygon pixels, the shape
factor
CircularityCircularityCircularityCircularitycircularity is defined as:
                    CircularityCircularityCircularityCircularitycircularity = F / (max^2 * pi)

The shape factor CircularityCircularityCircularityCircularitycircularity of a circle is 1. If the contour or polygon encloses an elongated area CircularityCircularityCircularityCircularitycircularity is smaller than 1. The operator circularity_xldcircularity_xldcircularity_xldCircularityXldCircularityXld especially responds to large bulges.

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

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 circularity_xldcircularity_xldcircularity_xldCircularityXldCircularityXld returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input contour 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

compactness_xldcompactness_xldcompactness_xldCompactnessXldCompactnessXld, convexity_xldconvexity_xldconvexity_xldConvexityXldConvexityXld, eccentricity_xldeccentricity_xldeccentricity_xldEccentricityXldEccentricityXld

See also

area_center_xldarea_center_xldarea_center_xldAreaCenterXldAreaCenterXld, select_shape_xldselect_shape_xldselect_shape_xldSelectShapeXldSelectShapeXld

Module

Foundation