thinning ( Region, StructElement1, StructElement2 : RegionThin : Row, Column, Iterations : )

Remove the result of a hit-or-miss operation from a region.

thinning performs a thinning of the input regions using morphological operations. The operator first applies a hit-or-miss-transformation to Region (cf.hit_or_miss), and then removes the detected points from the input region. The parameter Iterations determines the number of iterations performed.

For the choice of the structuring elements StructElement1 and StructElement2, as well as for Row and Column, the same restrictions described under hit_or_miss apply.

Structuring elements (StructElement1, StructElement2) 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 processed.

StructElement1 (input_object)
region -> object
Structuring element for the foreground.

StructElement2 (input_object)
region -> object
Structuring element for the background.

RegionThin (output_object)
region(-array) -> object
Result of the thinning operator.

Row (input_control)
point.y -> integer
Row coordinate of the reference point.
Default value: 0
Range of values: 0 <= Row <= 511 (lin)
Minimum increment: 1
Recommended increment: 1

Column (input_control)
point.x -> integer
Column coordinate of the reference point.
Default value: 0
Range of values: 0 <= Column <= 511 (lin)
Minimum increment: 1
Recommended increment: 1

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, F1 the area of the structuring element 1, and F2 the area of the structuring element 2. Then the runtime complexity for one object is:

      O(Iterations * sqrt(F) * (sqrt(F1) + sqrt(F2))) .


Result

thinning 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

reduce_domain, select_shape, area_center, connection


Alternatives

thinning_golay, thinning_seq


See also

hit_or_miss



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