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circularitycircularityCircularitycircularityCircularityCircularity (Operator)

Name

circularitycircularityCircularitycircularityCircularityCircularity — 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 Circularity(const HObject& Regions, HTuple* Circularity)

HTuple HRegion::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 circularitycircularityCircularitycircularityCircularityCircularity 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 = min(1,C')

The shape factor C of a circle is 1. If the region is long or has holes, C is smaller than 1. The operator circularitycircularityCircularitycircularityCircularityCircularity especially responds to large bulges, holes and unconnected regions. The value of C is clipped to 1.0, because the pixel area of a region can only be an approximation of a real circle's area. This approximation error is bigger for small regions than for large regions.

In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their circularity.

In case of an empty region the operator circularitycircularityCircularitycircularityCircularityCircularity returns the value 0 (if no other behavior was set (see set_systemset_systemSetSystemset_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

RegionsRegionsRegionsRegionsRegionsregions (input_object)  region(-array) → objectHRegionHRegionHRegionHRegionXHobject

Region(s) to be examined.

CircularityCircularityCircularityCircularityCircularitycircularity (output_control)  real(-array) → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Circularity 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 (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++ (HALCON 5.0-10.0))

#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 circularitycircularityCircularitycircularityCircularityCircularity 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>)SetSystem("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>)SetSystem("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

thresholdthresholdThresholdthresholdThresholdThreshold, regiongrowingregiongrowingRegiongrowingregiongrowingRegiongrowingRegiongrowing, connectionconnectionConnectionconnectionConnectionConnection

Alternatives

roundnessroundnessRoundnessroundnessRoundnessRoundness, compactnesscompactnessCompactnesscompactnessCompactnessCompactness, convexityconvexityConvexityconvexityConvexityConvexity, eccentricityeccentricityEccentricityeccentricityEccentricityEccentricity

See also

area_centerarea_centerAreaCenterarea_centerAreaCenterAreaCenter, select_shapeselect_shapeSelectShapeselect_shapeSelectShapeSelectShape

Module

Foundation

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HALCON Operator Reference 13.0.4 Copyright © 1996-2019 MVTec Software GmbH