Dilate a region with a circular structuring element.

::dilation_circle applies a Minkowski addition with a circular structuring element to the input regions Region. Because the circular mask is symmetrical, this is identical to a dilation. The size of the circle used as structuring element is determined by Radius.

The operator results in enlarged regions, smoothed region boundaries, and the holes smaller than the circular mask in the interior of the region are closed. It is useful to select only values like 3.5, 5.5, etc. for Radius in order to avoid a translation of a region, because integer radii result in the circle having a non-integer center of gravity which is rounded to the next integer.

::dilation_circle 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 'dilation_circle ()'" << endl;
  cout << "First = original image " << endl;
  cout << "Blue  = after dilation " << endl;
  cout << "Red   = before dilation " << endl;

  HByteImage img("monkey");
  HWindow    w;

  HRegion      circ   = HRegion::GenCircle (10, 10, 1.5);
  HRegionArray regs   = (img >= 128).Connection();
  HRegionArray minadd = regs.MinkowskiAdd1 (circ, 1);

                        img.Display (w);      w.Click ();
  w.SetColor ("blue");  minadd.Display (w);   w.Click ();
  w.SetColor ("red");   regs.Display (w);     w.Click ();

  return(0);
}

Let F1 be the area of an input region. Then the runtime complexity for one region is:

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

::dilation_circle 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

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

::minkowski_add1, ::minkowski_add2, ::expand_region, ::dilation1, ::dilation2, ::dilation_rectangle1

::gen_circle, ::erosion_circle, ::closing_circle, ::opening_circle

Morphology