area_centerarea_centerAreaCenterAreaCenterarea_center (Operator)
Name
area_centerarea_centerAreaCenterAreaCenterarea_center — Area and center of regions.
Signature
def area_center(regions: HObject) -> Tuple[Sequence[int], Sequence[float], Sequence[float]]
def area_center_s(regions: HObject) -> Tuple[int, float, float]
Description
The operator area_centerarea_centerAreaCenterAreaCenterarea_center calculates the area and the center
of the input regions. The area is defined as the number of
pixels of a region. The center is calculated as the mean value
of the line or column coordinates, respectively, of all pixels.
In the documentation of this chapter (Regions / Features), you can
find an image illustrating regions which vary in their area.
If more than one region is passed the results are stored in tuples,
the index of a value in the tuple corresponding to the index of the
input region. In case of empty region all parameters have the value 0.0
if no other behavior was set (see set_systemset_systemSetSystemSetSystemset_system).
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
Parameters
RegionsRegionsRegionsregionsregions (input_object) region(-array) → objectHRegionHObjectHObjectHobject
Region(s) to be examined.
AreaAreaAreaareaarea (output_control) integer(-array) → HTupleSequence[int]HTupleHtuple (integer) (int / long) (Hlong) (Hlong)
Area of the region.
RowRowRowrowrow (output_control) point.y(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)
Line index of the center.
ColumnColumnColumncolumncolumn (output_control) point.x(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)
Column index of the center.
Example (C++)
#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif
#include "HalconCpp.h"
using namespace Halcon;
main()
{
Tuple area, row, column;
HImage img ("monkey");
HWindow w;
img.Display (w);
w.Click ();
HRegionArray reg = (img >= 164).Connection ();
reg.Display (w);
w.Click ();
area = reg.AreaCenter (&row, &column);
for (int i = 0; i < reg.Num (); i++)
{
cout << "Row [" << i << "]" << "= " << row[i].D ();
cout << "\t\tColumn [" << i << "]" << "= " << column[i].D () << endl;
}
cout << "Total number of regions: " << reg.Num () << endl;
return(0);
}
Example (C)
threshold(&Image,&Seg,120.0,255.0);
connection(Seg,&Connected);
T_area_center(Connected,&Area,&Row,&Column);
Example (C++)
#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif
#include "HalconCpp.h"
using namespace Halcon;
main()
{
Tuple area, row, column;
HImage img ("monkey");
HWindow w;
img.Display (w);
w.Click ();
HRegionArray reg = (img >= 164).Connection ();
reg.Display (w);
w.Click ();
area = reg.AreaCenter (&row, &column);
for (int i = 0; i < reg.Num (); i++)
{
cout << "Row [" << i << "]" << "= " << row[i].D ();
cout << "\t\tColumn [" << i << "]" << "= " << column[i].D () << endl;
}
cout << "Total number of regions: " << reg.Num () << endl;
return(0);
}
Example (C++)
#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif
#include "HalconCpp.h"
using namespace Halcon;
main()
{
Tuple area, row, column;
HImage img ("monkey");
HWindow w;
img.Display (w);
w.Click ();
HRegionArray reg = (img >= 164).Connection ();
reg.Display (w);
w.Click ();
area = reg.AreaCenter (&row, &column);
for (int i = 0; i < reg.Num (); i++)
{
cout << "Row [" << i << "]" << "= " << row[i].D ();
cout << "\t\tColumn [" << i << "]" << "= " << column[i].D () << endl;
}
cout << "Total number of regions: " << reg.Num () << endl;
return(0);
}
Complexity
If F is the area of a region the mean runtime
complexity is O(sqrt(F)).
Result
The operator area_centerarea_centerAreaCenterAreaCenterarea_center 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>)SetSystem("no_object_result",<Result>)set_system("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>)SetSystem("empty_region_result",<Result>)set_system("empty_region_result",<Result>).
If necessary an exception is raised.
Possible Predecessors
thresholdthresholdThresholdThresholdthreshold,
regiongrowingregiongrowingRegiongrowingRegiongrowingregiongrowing,
connectionconnectionConnectionConnectionconnection
See also
select_shapeselect_shapeSelectShapeSelectShapeselect_shape
Module
Foundation