Close a region.

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

Structuring elements (StructElement) can be generated with operators such as ::gen_circle, ::gen_rectangle1, ::gen_rectangle2, ::gen_ellipse, ::draw_region, ::gen_region_polygon, ::gen_region_points, etc.

::closing is applied to each input region separately. If gaps between different regions are to be closed, ::union1 or ::union2 has to be called first.

#include  <iostream.h>
#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);
}

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:

    O(2 * sqrt(F1) * sqrt(F2)) .

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

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

::threshold, ::regiongrowing, ::connection, ::union1, ::watersheds, ::class_ndim_norm, ::gen_circle, ::gen_ellipse, ::gen_rectangle1, ::gen_rectangle2, ::draw_region, ::gen_region_points, ::gen_struct_elements, ::gen_region_polygon_filled

::reduce_domain, ::select_shape, ::area_center, ::connection

::closing_circle, ::closing_golay

::dilation1, ::erosion1, ::opening, ::minkowski_sub1

Morphology