HALCON Reference Manual 10.0.2
Table of Contents / Regions / Features ClassesClassesClasses | | | Operators

circularitycircularitycircularityCircularityCircularity (Operator)

Name

circularitycircularitycircularityCircularityCircularity — Shape factor for the circularity (similarity to a circle) of a region.

Signature

circularity(Regions : : : Circularity)

Herror circularity(const Hobject Regions, double* Circularity)

Herror T_circularity(const Hobject Regions, Htuple* Circularity)

Herror circularity(Hobject Regions, double* Circularity)

Herror circularity(Hobject Regions, HTuple* Circularity)

double HRegion::Circularity() const

HTuple HRegionArray::Circularity() const

void HOperatorSetX.Circularity(
[in] IHUntypedObjectX* Regions, [out] VARIANT* Circularity)

VARIANT HRegionX.Circularity()

static void HOperatorSet.Circularity(HObject regions, out HTuple circularity)

HTuple HRegion.Circularity()

Description

The operator circularitycircularitycircularityCircularityCircularity calculates the similarity of the input region with a circle.

Calculation:

If F is the area of the region and max is the maximum distance from the center to all contour pixels, the shape factor C is defined as:

C = F / (max^2 * pi)

The shape factor C of a circle is 1. If the region is long or has holes C is smaller than 1. The operator circularitycircularitycircularityCircularityCircularity especially responds to large bulges, holes and unconnected regions.

In case of an empty region the operator circularitycircularitycircularityCircularityCircularity returns the value 0 (if no other behavior was set (see set_systemset_systemset_systemSetSystemSetSystem)). If more than one region is passed the numerical values of the shape factor are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.

Parallelization

Parameters

RegionsRegionsRegionsRegionsregions (input_object)  region(-array) → objectHRegionHRegionHRegionXHobject

Region(s) to be examined.

CircularityCircularityCircularityCircularitycircularity (output_control)  real(-array) → HTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double)

Roundness of the input region(s).

Assertion: (0 <= Circularity) && (Circularity <= 1.0)

Example (HDevelop)

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

Example (C)

/* Comparison between shape factors of rectangle, circle and ellipse */
gen_rectangle1(&R1,10.0,10.0,20.0,20.0);
gen_rectangle2(&R2,100.0,100.0,0.0,100.0,20.0);
gen_ellipse(&E,100.0,100.0,0.0,100.0,20.0);
gen_circle(&C,100.0,100.0,20.0);
circularity(R1,&R1_);
circularity(R2,&R2_);
circularity(E,&E_);
circularity(C,&C_);
printf("quadrate:   %g\n",R1_);
printf("rectangle:  %g\n",R2_);
printf("ellipse:    %g\n",E_);
printf("circle:     %g\n",C_);

Example (C++)

#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif
#include "HalconCpp.h"
using namespace Halcon;

int main (int argc, char *argv[])
{
  if (argc < 2)
  {
    cout << "Usage: " << argv[0] << " <# of regions> " << endl;
    return (-1);
  }

  HWindow        w;
  HRegionArray   reg;

  int NumOfElements = atoi (argv[1]);

  cout << "Draw " << NumOfElements << " regions " << endl;

  for (int i=0; i < NumOfElements; i++)
  {
    reg[i] = w.DrawRegion ();
  }

  Tuple circ = reg.Circularity ();
  Tuple cont = reg.Contlength ();

  for (i = 0; i < NumOfElements; i++)
  {
    cout << "Circularity of " << i+1 << ". region = " << circ[i].D();
    cout << "\t\t Contour Length of" << i+1 <<
            ". region = " << cont[i].D() << endl;
  }

  w.Click ();
  return(0);
}

Example (HDevelop)

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

Example (HDevelop)

* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate:  ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse:   ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle:    ',M_C])
fnew_line(FileId)

Result

The operator circularitycircularitycircularityCircularityCircularity returns the value 2 (H_MSG_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>)set_system("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("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>)set_system("empty_region_result",<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

thresholdthresholdthresholdThresholdThreshold, regiongrowingregiongrowingregiongrowingRegiongrowingRegiongrowing, connectionconnectionconnectionConnectionConnection

Alternatives

roundnessroundnessroundnessRoundnessRoundness, compactnesscompactnesscompactnessCompactnessCompactness, convexityconvexityconvexityConvexityConvexity, eccentricityeccentricityeccentricityEccentricityEccentricity

See also

area_centerarea_centerarea_centerAreaCenterAreaCenter, select_shapeselect_shapeselect_shapeSelectShapeSelectShape

Module

Foundation

Table of Contents / Regions / Features ClassesClassesClasses | | | Operators
HALCON Reference Manual 10.0.2 Copyright © 1996-2011 MVTec Software GmbH