erosion_seq ( Region : RegionErosion : GolayElement, Iterations : )

Erode a region sequentially.

erosion_seq computes the sequential erosion of the input region Region with the selected structuring element GolayElement from the Golay alphabet. This is done by executing the operator erosion_golay with all rotations of the structuring element Iterations times. The following structuring elements can be selected:

'l', 'd', 'c', 'f', 'h', 'k'.

Only the ``foreground elements'' (even rotation numbers) are used. The elements 'i' and 'e' result in unchanged output regions. The elements 'l', 'm'. anf 'f2' are identical for the foreground. The Golay elements, together with all possible rotations, are described with the operator golay_elements.


Parameters

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

RegionErosion (output_object)
region(-array) -> object
Eroded regions.

GolayElement (input_control)
string -> string
Structuring element from the Golay alphabet.
Default value: 'h'
List of values: 'l', 'd', 'c', 'f', 'h', 'k'

Iterations (input_control)
integer -> integer
Number of iterations.
Default value: 1
Suggested values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 30, 40, 50
Range of values: 1 <= Iterations
Minimum increment: 1
Recommended increment: 1


Complexity

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

       O(Iterations * 20 * sqrt(F)) .


Result

erosion_seq 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__, watersheds, class_ndim1__


Possible Successors

connection, reduce_domain, select_shape, area_center


Alternatives

erosion_golay, erosion1, erosion2


See also

dilation_seq, hit_or_miss_seq, thinning_seq



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