erosion_seqErosionSeqErosionSeqerosion_seqerosion_seq🔗

Short description🔗

erosion_seqErosionSeqErosionSeqerosion_seqerosion_seq — Erode a region sequentially.

Warning🔗

erosion_seqErosionSeq is obsolete and is only provided for reasons of backward compatibility.

Signature🔗

erosion_seq( region Region, out region RegionErosion, string GolayElement, integer Iterations )

Description🔗

erosion_seqErosionSeq computes the sequential erosion of the input region Regionregionregion with the selected structuring element GolayElementgolayElementgolay_element from the Golay alphabet. This is done by executing the operator erosion_golayErosionGolay with all rotations of the structuring element Iterationsiterationsiterations 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’ and ‘f2’ are identical for the foreground. The Golay elements, together with all possible rotations, are described with the operator golay_elementsGolayElements.

Execution information🔗

Execution information

Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
Automatically parallelized on tuple level.

Parameters🔗

Regionregionregion (input_object) region(-array) → objectHObjectHRegionHObjectHobject

Regions to be eroded.

RegionErosionregionErosionregion_erosion (output_object) region(-array) → objectHObjectHRegionHObjectHobject *

Eroded regions.

GolayElementgolayElementgolay_element (input_control) string → (string)HTuple (HString)HTuple (string)strHtuple (char*)

Structuring element from the Golay alphabet.

Default: 'h'"h"
List of values: 'c', 'd', 'f', 'h', 'k', 'l'"c", "d", "f", "h", "k", "l"

Iterationsiterationsiterations (input_control) integer → (integer)HTuple (Hlong)HTuple (int / long)intHtuple (Hlong)

Number of iterations.

Default: 11
Suggested values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 30, 40, 50
Value range: 1 ≤ Iterations (lin)
Minimum increment: 1
Recommended increment: 1

Complexity🔗

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

\[\begin{eqnarray*} O(\textrm{Iterations} \cdot 20 \cdot \sqrt{F}) \enspace . \end{eqnarray*}\]

Result🔗

erosion_seqErosionSeq returns 2 (H_MSG_TRUE) if all parameters are correct. The behavior in case of empty or no input region can be set via:

no region: set_system('no_object_result',<RegionResult>)
empty region: set_system('empty_region_result',<RegionResult>)

Otherwise, an exception is raised.

Combinations with other operators🔗

Combinations

Possible predecessors

thresholdThreshold, regiongrowingRegiongrowing, watershedsWatersheds, class_ndim_normClassNdimNorm

Possible successors

connectionConnection, reduce_domainReduceDomain, select_shapeSelectShape, area_centerAreaCenter

Alternatives

erosion_golayErosionGolay, erosion1Erosion1, erosion2Erosion2

Module🔗

Foundation