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RegionCircularity

Header:	AVL.h
Namespace:	avl
Module:	FoundationBasic

Computes the area of a region divided by the area of a circular region having the same feature.

Syntax

void avl::RegionCircularity
(
	const avl::Region& inRegion,
	const avl::CircularityMeasure::Type inCircularityMeasure,
	float& outCircularity,
	avl::Circle2D& diagCircle
)

Parameters

Name	Type	Default	Description
inRegion	const Region&		Input region
inCircularityMeasure	const CircularityMeasure::Type	RadiusPreserving	Which algorithm should be used to compute a circle
outCircularity	float&
diagCircle	Circle2D&		Computed circle which area was compared.

Description

Circularity is a measure of similarity of a region shape to the perfect circle. Circular regions have circularity close to 1.0, while the more elongated the region is (or contains more holes), the closer to 0.0 is its circularity.

Mathematically, the circularity is calculated as follows: Where c denotes a circular region having the same feature as input region r. The feature being considered depends on the inCircularityMeasure chosen and it is:

the minimal bounding circle in case of BoundingCirclePreserving
the perimeter in case of PerimeterPreserving
the radius (maximal distance from mass center to any of the region pixels) in case of RadiusPreserving

Hints

If the input region is not guaranteed to be non-empty, precede this filter with SkipEmptyRegion.

Examples

Circularity with RadiusPreserving of the sample region equals to 0.667.

Circularity with PerimeterPreserving of the sample region equals to 1.000.

Errors

List of possible exceptions:

Error type	Description
DomainError	Empty region on input in RegionCircularity.
DomainError	Not supported circularity measure in RegionCircularity.