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# AVL.RegionCircularity

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

Namespace: AvlNet AVL.NET.dll

### Syntax

C++
C#

public static void RegionCircularity
(
AvlNet.Region inRegion,
AvlNet.CircularityMeasure inCircularityMeasure,
out float outCircularity,
out AvlNet.Circle2D diagCircle
)


### Parameters

Name Type Range Default Description
inRegionAvlNet.RegionInput region.
inCircularityMeasureAvlNet.CircularityMeasureRadiusPreservingWhich algorithm should be used to compute a circle. Default value: RadiusPreserving.
outCircularityfloat
diagCircleAvlNet.Circle2DComputed 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

### 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 Degenerate region on input in RegionCircularity.
DomainError Not supported circularity measure in RegionCircularity.