Dilate a region with a rectangular structuring element.

dilation_rectangle1 applies a dilation with a rectangular structuring element to the input regions Region. The size of the structuring rectangle is Width x Height. The operator results in enlarged regions, and the holes smaller than the rectangular mask in the interior of the regions are closed.

dilation_rectangle1 is a very fast operation because the height of the rectangle enters only logarithmically into the runtime complexity, while the width does not enter at all. This leads to excellent runtime efficiency, even in the case of very large rectangles (edge length > 100).

dilation_rectangle1 is applied to each input region separately. If gaps between different regions are to be closed, union1 or union2 has to be called first.

To enlarge a region by the same amount in all directions, Width and Height must be odd. If this is not the case, the region is dilated by a larger amount at the right or at the bottom, respectively, than at the left or at the top.

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

main()
{
  cout << "Reproduction of 'dilation_rectangle ()'" << endl;
  cout << "First = original image " << endl;
  cout << "Blue  = after dilation " << endl;
  cout << "Red   = after segmentation " << endl;

  HByteImage img("monkey");
  HWindow    w;

  HRegionArray regs   = (img >= 220).Connection();
  HRegionArray dilreg = regs.DilationRectangle1 (2, 4);

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

  return(0);
}

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

       O(sqrt(F1) * ld(H)) .

dilation_rectangle1 returns 2 (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>)

dilation_rectangle1 is reentrant and automatically parallelized (on tuple level).

threshold, regiongrowing, connection, union1, watersheds, class_ndim_norm

reduce_domain, select_shape, area_center, connection

minkowski_add1, minkowski_add2, expand_region, dilation1, dilation2, dilation_circle

gen_rectangle1, gen_region_polygon_filled

Foundation