compactnesscompactnessCompactnesscompactnessCompactnessCompactness (Operator)

Name

compactnesscompactnessCompactnesscompactnessCompactnessCompactness — Shape factor for the compactness of a region.

Signature

Description

The operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness calculates the compactness of the input regions.

Calculation:

If L is the length of the contour (see contlengthcontlengthContlengthcontlengthContlengthContlength) and F the area of the region the shape factor C is defined as:

C' = L^2 / (4 F pi)

C = max(1,C')

The shape factor C of a circle is 1. If the region is long or has holes C is larger than 1. The operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness responds to the course of the contour (roughness) and to holes. The value of C is clipped to 1.0, because the pixel area of a region can only be an approximation of a real circle's area. This approximation error is bigger for small regions than for large regions.

In case of an empty region the operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness returns the value 0 if no other behavior was set (see set_systemset_systemSetSystemset_systemSetSystemSetSystem). If more than one region is passed the numerical values of the shape factor are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.

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 compactnesscompactnessCompactnesscompactnessCompactnessCompactness returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input regions available) is set via the operator set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). The behavior in case of empty region (the region is the empty set) is set via set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

thresholdthresholdThresholdthresholdThresholdThreshold, regiongrowingregiongrowingRegiongrowingregiongrowingRegiongrowingRegiongrowing, connectionconnectionConnectionconnectionConnectionConnection

Alternatives

convexityconvexityConvexityconvexityConvexityConvexity, eccentricityeccentricityEccentricityeccentricityEccentricityEccentricity

See also

contlengthcontlengthContlengthcontlengthContlengthContlength, area_centerarea_centerAreaCenterarea_centerAreaCenterAreaCenter, select_shapeselect_shapeSelectShapeselect_shapeSelectShapeSelectShape

Module

Foundation