dilation_rectangle1 ( Region : RegionDilation : Width, Height : )

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 the region being enlarged, and the closing of holes smaller than the rectangular mask in the interior of the region.

dilation_rectangle1 is a very fast operation because the height of the rectangle only enters 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 (edge length > 100).


Attention

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.


Parameters

Region (input_object)
region(-array) -> object
Regions to be dilated.

RegionDilation (output_object)
region(-array) -> object
Dilated regions.

Width (input_control)
extent.x -> integer
Width of the structuring rectangle.
Default value: 10
Suggested values: 1, 2, 3, 4, 6, 10, 15, 20, 30, 50, 70, 100, 150, 200
Range of values: 1 <= Width <= 511 (lin)
Minimum increment: 1
Recommended increment: 10

Height (input_control)
extent.y -> integer
Height of the structuring rectangle.
Default value: 10
Suggested values: 1, 2, 3, 4, 6, 10, 15, 20, 30, 50, 70, 100, 150, 200
Range of values: 1 <= Height <= 511 (lin)
Minimum increment: 1
Recommended increment: 10


Example
#include  
#include  "HCPP.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("affe");
  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);
}

Complexity

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

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


Result

dilation_rectangle1 returns 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>:)
Otherwise, an exception is raised.


Possible Predecessors

threshold__, regiongrowing__, connection, union1, watersheds, class_ndim1__


Possible Successors

reduce_domain, select_shape, area_center, connection


Alternatives

minkowski_add1, minkowski_add2, expand, dilation1, dilation2, dilation_circle


See also

rectangle1, store_polygon



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