thinning_seqthinning_seqthinning_seqThinningSeqThinningSeq (Operator)

Name

thinning_seqthinning_seqthinning_seqThinningSeqThinningSeq — Remove the result of a hit-or-miss operation from a region (sequential).

Signature

Description

thinning_seqthinning_seqthinning_seqThinningSeqThinningSeq calculates the sequential thinning of the input regions with a structuring element from the Golay alphabet (GolayElementGolayElementGolayElementGolayElementgolayElement). To do so, thinning_seqthinning_seqthinning_seqThinningSeqThinningSeq calls the operator thinning_golaythinning_golaythinning_golayThinningGolayThinningGolay with all possible rotations of the structuring element IterationsIterationsIterationsIterationsiterations times. If IterationsIterationsIterationsIterationsiterations is chosen large enough, the operator calculates the skeleton of a region if the structuring elements 'l' or 'm' are used. For the element 'c' the background and foreground are exchanged in order to have an effect on the interior boundary of a region. If a very large value or 'maximal' is passed for IterationsIterationsIterationsIterationsiterations the iteration stops if no more changes occur. The following structuring elements are available:

'l'

Skeleton, similar to skeletonskeletonskeletonSkeletonSkeleton. This structuring element is also used in morph_skizmorph_skizmorph_skizMorphSkizMorphSkiz.

'm'

A skeleton with many “hairs” and multiple (parallel) branches.

'd'

A skeleton without multiple branches, but with many gaps, similar to morph_skeletonmorph_skeletonmorph_skeletonMorphSkeletonMorphSkeleton.

'c'

Uniform erosion of the region.

'e'

One pixel wide lines are shortened. This structuring element is also used in morph_skizmorph_skizmorph_skizMorphSkizMorphSkiz.

'i'

Isolated points are removed. (Only IterationsIterationsIterationsIterationsiterations = 1 is useful.)

'f'

Y-junctions are eliminated. (Only IterationsIterationsIterationsIterationsiterations = 1 is useful.)

'f2'

One pixel long branches and corners are removed. (Only IterationsIterationsIterationsIterationsiterations = 1 is useful.)

'h'

A kind of inner boundary, which, however, is thicker than the result of boundaryboundaryboundaryBoundaryBoundary, is generated. (Only IterationsIterationsIterationsIterationsiterations = 1 is useful.)

'k'

Junction points are eliminated, but also new ones are generated.

The Golay elements, together with all possible rotations, are described with the operator golay_elementsgolay_elementsgolay_elementsGolayElementsGolayElements.

Parallelization

• 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

Complexity

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

      O(Iterations * 6 * sqrt(F)) .

Result

thinning_seqthinning_seqthinning_seqThinningSeqThinningSeq 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.

Possible Predecessors

thresholdthresholdthresholdThresholdThreshold, regiongrowingregiongrowingregiongrowingRegiongrowingRegiongrowing, connectionconnectionconnectionConnectionConnection, union1union1union1Union1Union1, watershedswatershedswatershedsWatershedsWatersheds, class_ndim_normclass_ndim_normclass_ndim_normClassNdimNormClassNdimNorm, gen_circlegen_circlegen_circleGenCircleGenCircle, gen_ellipsegen_ellipsegen_ellipseGenEllipseGenEllipse, gen_rectangle1gen_rectangle1gen_rectangle1GenRectangle1GenRectangle1, gen_rectangle2gen_rectangle2gen_rectangle2GenRectangle2GenRectangle2, draw_regiondraw_regiondraw_regionDrawRegionDrawRegion, gen_region_pointsgen_region_pointsgen_region_pointsGenRegionPointsGenRegionPoints, gen_struct_elementsgen_struct_elementsgen_struct_elementsGenStructElementsGenStructElements, gen_region_polygon_filledgen_region_polygon_filledgen_region_polygon_filledGenRegionPolygonFilledGenRegionPolygonFilled

Possible Successors

pruningpruningpruningPruningPruning, reduce_domainreduce_domainreduce_domainReduceDomainReduceDomain, select_shapeselect_shapeselect_shapeSelectShapeSelectShape, area_centerarea_centerarea_centerAreaCenterAreaCenter, connectionconnectionconnectionConnectionConnection, complementcomplementcomplementComplementComplement

Alternatives

skeletonskeletonskeletonSkeletonSkeleton, morph_skizmorph_skizmorph_skizMorphSkizMorphSkiz, expand_regionexpand_regionexpand_regionExpandRegionExpandRegion

See also

hit_or_miss_seqhit_or_miss_seqhit_or_miss_seqHitOrMissSeqHitOrMissSeq, erosion_golayerosion_golayerosion_golayErosionGolayErosionGolay, differencedifferencedifferenceDifferenceDifference, thinning_golaythinning_golaythinning_golayThinningGolayThinningGolay, thinningthinningthinningThinningThinning, thickening_seqthickening_seqthickening_seqThickeningSeqThickeningSeq

Module

Foundation