opening_seg ( Region, StructElement : RegionOpening : : )

Separate overlapping regions.

The opening_seg operation is defined as a sequence of the following operators: erosion1, connection and dilation1 (see example). Only one iteration is done in erosion1 and dilation1.

opening_seg serves to separate overlapping regions whose area of overlap is smaller than StructElement. It should be noted that the resulting regions can overlap without actually merging (see expand). opening_seg uses the center of gravity as the reference point of the structuring element.

Structuring elements (StructElement) can be generated with operators such as circle, rectangle1, rectangle2, ellipse, draw_region, store_polygon, store_coord, etc.


Parameters

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

StructElement (input_object)
region -> object
Structuring element (position-invariant).

RegionOpening (output_object)
region-array -> object
Opened regions.


Example
/* Simulation of opening_seg */
opening_seg(Region,StructElement:RegionOpening::):
    erosion1(Region,StructElement:H1:1:) >
    connection(H1:H2::) >
    dilation1(H2,StructElement:RegionOpening:1:) >
    clear([H1,H2]:::).

Complexity

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

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


Result

opening_seg 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__, circle, ellipse, rectangle1, rectangle2, draw_region, store_coord, struct_elements, store_filled_polygon


Possible Successors

expand, reduce_domain, select_shape, area_center, connection


Alternatives

erosion1, connection, dilation1



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