HALCON Reference Manual / Morphology / Region Operators

erosion2 (Operator)

Name

erosion2 — Erode a region (using a reference point).

Synopsis

erosion2(Region, StructElement : RegionErosion : Row, Column, Iterations : )

Description

erosion2 erodes the input regions with a structuring element (StructElement) having the reference point (Row,Column). erosion2 has a similar effect as erosion1, the difference is that the reference point of the structuring element can be chosen arbitrarily. The parameter Iterations determines the number of iterations which are to be performed with the structuring element. The result of iteration n-1 is used as input for iteration n.

A maximum region is generated in case of an empty structuring element.

Structuring elements (StructElement) can be generated with operators such as gen_circle, gen_rectangle1, gen_rectangle2, gen_ellipse, draw_region, gen_region_polygon, gen_region_points, etc.

Parameters

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

StructElement (input_object) region object
Structuring element.

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

Row (input_control) point.y (integer)
Row coordinate of the reference point.
Default value: 0
Typical 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
Typical 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
Typical range of values: 1 ≤ Iterations (lin)
Minimum increment: 1
Recommended increment: 1

Complexity

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

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

Result

erosion2 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>)

Otherwise, an exception is raised.

Parallelization Information

erosion2 is reentrant and automatically parallelized (on tuple level).

Possible Predecessors

threshold, regiongrowing, watersheds, class_ndim_norm, gen_circle, gen_ellipse, gen_rectangle1, gen_rectangle2, draw_region, gen_region_points, gen_struct_elements, gen_region_polygon_filled

Possible Successors

reduce_domain, select_shape, area_center, connection

Alternatives

minkowski_sub2, minkowski_sub1, erosion1, erosion_golay, erosion_seq

See also

transpose_region, gen_circle, gen_rectangle2, gen_region_polygon

Module

Foundation


HALCON Reference Manual / Morphology / Region Operators
Version 9.0.2 Copyright © 1996-2010 MVTec Software GmbH