DIPlib Documentation - ©1995-2014 Quantitative Imaging Group, Delft University of Technology.

FeatureP2A

Measure the circularity of the object

SYNOPSIS

#include "dip_measurement.h"

dip_int dip_FeatureP2AID ( void )

OUTPUT DATA TYPE

dip_float

FUNCTION

dip_FeatureP2AID returns the ID value of this measurement function, that is registered by Initialise.

This function is a composite measurement function, that uses FeatureSize, FeaturePerimeter, and FeatureSurfaceArea to determine the circularity of an object by calculating: 2D: P2A = perimeter^2 / (4Pi * size) 3D: P2A = surface-area^1.5 / (6 Sqrt(Pi) * size)

NOTE

This function ignores any physical dimensions passed through the Measure function. The units are always pixels.

NOTE

This function uses chain codes. It expects each measured object to be compact, that is, to have only one chain code. Additional chain codes are ignored, meaning that non-compact objects are not measured properly. Take care in providing the correct connectivity value: if you object is compact only with 2-connectivity, this measure will fail if you call Measure with a value of 1 for the connectivity.

SEE ALSO

Measure

FeatureAnisotropy2D, FeatureBendingEnergy, FeatureCenter, FeatureChainCodeBendingEnergy, FeatureConvexArea, FeatureConvexPerimeter, FeatureConvexity, FeatureDimension, FeatureExcessKurtosis, FeatureFeret, FeatureGinertia, FeatureGmu, FeatureGravity, FeatureInertia, FeatureLongestChaincodeRun, FeatureMass, FeatureMaxVal, FeatureMaximum, FeatureMean, FeatureMinVal, FeatureMinimum, FeatureMu, FeatureOrientation2D, FeatureP2A, FeaturePerimeter, FeatureRadius, FeatureShape, FeatureSize, FeatureSkewness, FeatureStdDev, FeatureSum, FeatureSurfaceArea