RegionsOperatorsmRgnPerimeterRatio Method |
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Ratio of perimeter to convex perimeter.
Namespace: MediaCy.IQL.Operators
Assembly: MediaCy.IQL.Operators (in MediaCy.IQL.Operators.dll) Version: 3.1.0.0
SyntaxVB
<ExtensionAttribute> Public Shared Function mRgnPerimeterRatio ( regions As McRegions ) As McMeasure
Parameters
- regions
- Type: MediaCy.IQL.FeaturesMcRegions
Return Value
Type: McMeasureUsage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type McRegions. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).RemarksThis is computed as mRgnConvexPerimeter / mRgnPerimeter. The maximum
value is 1.0, which will be found for purely convex region boundaries.
Note that region features of Type mcftScanList (ones created by the
McThreshold.Execute method or McFeatures.SetFromMask methods) will usually
have one-pixel sized non-convex transitions even for purely convex blobs.
The weak filtering of mRgnPerimeter for these features usually acts to keep
mRgnPerimeterRatio to its maximum value of one, in spite of these
irregularities. See mRgnPerimeter for more discussion of the rationale
behind this filtering.
This is a boundary geometry based measurement, so it is independent of pixel
counts and is accurate for sub-pixel locations of region boundaries. It is
only valid for boundaries that do not cross themselves (i.e., no
figure-8's).
See Also