excentricity ( Regions : : : Anisometry, Bulkiness, StructureFactor )

Shape features derived from the ellipse parameters.

The operator excentricity calculates three shape features derived from the geometric moments.

Definition: If the ellipse radii $ra$, $rb$ and the area $F$ of the
            region are given (see moments,
elliptic_axis),
            the following applies:
                           Anisometry = ra / rb
                           Bulkiness = 4 pi ra rb / F
                           StructureFactor = (4 pi rb - F) / F
In case of empty region all parameters have the value 0.0 if no other behavior was set (see set_system).


Parameters

Regions (input_object)
region(-array) -> object
Region(s) to be examined.

Anisometry (output_control)
real(-array) -> real
Shape feature (in case of a circle = 1.0).
Assertion: Anisometry >= 1.0

Bulkiness (output_control)
real(-array) -> real
Calculated shape feature.

StructureFactor (output_control)
real(-array) -> real
Calculated shape feature.


Complexity

If F is the area of the region the mean runtime complexity is O(F).


Result

The operator excentricityreturns the value 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>:). The behavior in case of empty region (the region is the empty set) is set via set_system(::'empty_region_result',<Result>:). If necessary an exception is raised.


Possible Predecessors

threshold__, regiongrowing__, connection


See also

elliptic_axis, moments, select_shape, area_center



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