closingClosingClosingclosingclosing🔗

Short description🔗

closingClosingClosingclosingclosing — Close a region.

Signature🔗

closing( region Region, region StructElement, out region RegionClosing )

Description🔗

A closingClosing operation is defined as a dilation followed by a Minkowski subtraction. By applying closingClosing to a region, larger structures remain mostly intact, while small gaps between adjacent regions and holes smaller than StructElementstructElementstruct_element are closed, and the regions’ boundaries are smoothed. All closingClosing variants share the property that separate regions are not merged, but remain separate objects. The position of StructElementstructElementstruct_element is meaningless, since a closing operation is invariant with respect to the choice of the reference point.

Structuring elements (StructElementstructElementstruct_element) can be generated with operators such as gen_circleGenCircle, gen_rectangle1GenRectangle1, gen_rectangle2GenRectangle2, gen_ellipseGenEllipse, draw_regionDrawRegion, gen_region_polygonGenRegionPolygon, gen_region_pointsGenRegionPoints, etc.

Attention🔗

closingClosing is applied to each input region separately. If gaps between different regions are to be closed, union1Union1 or union2Union2 has to be called first.

Execution information🔗

Execution information

Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).

Parameters🔗

Regionregionregion (input_object) region(-array) → objectHObjectHRegionHObjectHobject

Regions to be closed.

StructElementstructElementstruct_element (input_object) region → objectHObjectHRegionHObjectHobject

Structuring element (position-invariant).

RegionClosingregionClosingregion_closing (output_object) region(-array) → objectHObjectHRegionHObjectHobject *

Closed regions.

Example🔗

(C)

my_closing(Hobject In, Hobject StructElement, Hobject *Out)
{
  Hobject  tmp\;
  dilation1(In,StructElement,&tmp,1)\;
  minkowski_sub1(tmp,StructElement,Out,1)\;
}

(C++)

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

main()
{
  cout << "Reproduction of 'closing ()' using " << endl\;
  cout << "'dilation()' and 'minkowski_sub1()'" << endl\;
 HByteImage img("monkey")\;
  HWindow    w\;
 HRegion      circ = HRegion::GenCircle (10, 10, 1.5)\;
  HRegionArray regs = (img >= 128).Connection()\;
 HRegionArray dilreg = regs.Dilation1 (circ, 1)\;
  HRegionArray minsub = dilreg.MinkowskiSub1 (circ, 1)\;
                       img.Display (w)\;      w.Click ()\;
  w.SetColor ("red")\;   regs.Display (w)\;     w.Click ()\;
  w.SetColor ("green")\; dilreg.Display (w)\;   w.Click ()\;
  w.SetColor ("blue")\;  minsub.Display (w)\;   w.Click ()\;
 return(0)\;
}

Complexity🔗

Let \(F1\) be the area of the input region, and \(F2\) be the area of the structuring element. Then the runtime complexity for one region is:

\[\begin{eqnarray*} O(2 \cdot \sqrt{F1} \cdot \sqrt{F2}) \enspace . \end{eqnarray*}\]

Result🔗

closingClosing returns 2 (H_MSG_TRUE) if all parameters are correct. The behavior in case of empty or no input region can be set via:

no region: set_system('no_object_result',<RegionResult>)
empty region: set_system('empty_region_result',<RegionResult>)

Otherwise, an exception is raised.

Combinations with other operators🔗

Combinations

Possible predecessors

thresholdThreshold, regiongrowingRegiongrowing, connectionConnection, union1Union1, watershedsWatersheds, class_ndim_normClassNdimNorm, gen_circleGenCircle, gen_ellipseGenEllipse, gen_rectangle1GenRectangle1, gen_rectangle2GenRectangle2, draw_regionDrawRegion, gen_region_pointsGenRegionPoints, gen_region_polygon_filledGenRegionPolygonFilled

Possible successors

reduce_domainReduceDomain, select_shapeSelectShape, area_centerAreaCenter, connectionConnection

Alternatives

closing_circleClosingCircle

Module🔗

Foundation