union_adjacent_contours_xldunion_adjacent_contours_xldunion_adjacent_contours_xldUnionAdjacentContoursXldUnionAdjacentContoursXld (Operator)

Name

union_adjacent_contours_xldunion_adjacent_contours_xldunion_adjacent_contours_xldUnionAdjacentContoursXldUnionAdjacentContoursXld — Compute the union of contours whose end points are close together.

Signature

Description

The operator union_adjacent_contours_xldunion_adjacent_contours_xldunion_adjacent_contours_xldUnionAdjacentContoursXldUnionAdjacentContoursXld unifies all contours of the input XLD contour array (ContoursContoursContoursContourscontours) whose end points are close together. The unified contour consists of the concatenation of the contour points of the input contours. If necessary, the order of these input contour points is flipped, so that the end points of the contours that have to be connected are direct neighbors in the resulting point list. This operation is repeated until there are no more unconnected adjacent contours left. As a result all the contours that are newly created by unification, as well as the input contours that could not be connected with any other contour, are returned in UnionContoursUnionContoursUnionContoursUnionContoursunionContours.

The neighbored endpoints of two contours are connected if the distance between these end points neither exceeds an absolute threshold (MaxDistAbsMaxDistAbsMaxDistAbsMaxDistAbsmaxDistAbs) nor a relative threshold that is defined by the length of the longer contour multiplied by MaxDistRelMaxDistRelMaxDistRelMaxDistRelmaxDistRel.

The order for connecting adjacent contours depends mainly on the distance of the neighbored end points: the contours with the smallest distance are connected first. If there are two paires of contours with the same distance, first the contour pair that does not contain the shortest contour is connected.

Finally, by the parameter ModeModeModeModemode it is possible to control how to handle the attributes that may come with input contours. For example, the operator edges_sub_pixedges_sub_pixedges_sub_pixEdgesSubPixEdgesSubPix attaches to every contour point attributes like the local orientation, the edge response, and the edge direction. Choosing the default value 'attr_keep'"attr_keep""attr_keep""attr_keep""attr_keep", all attributes are copied to the output, and - if a contour has to be flipped for connecting it with another one - they are adapted to the new orientation. With a great number of input contours, however, it may be sensible to ignore the attributes for performance reasons, if they are not needed for further calculations. For this the value 'attr_forget'"attr_forget""attr_forget""attr_forget""attr_forget" has to be passed.

Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

Parameters

Possible Predecessors

split_contours_xldsplit_contours_xldsplit_contours_xldSplitContoursXldSplitContoursXld, select_contours_xldselect_contours_xldselect_contours_xldSelectContoursXldSelectContoursXld

Alternatives

union_collinear_contours_xldunion_collinear_contours_xldunion_collinear_contours_xldUnionCollinearContoursXldUnionCollinearContoursXld, union_collinear_contours_ext_xldunion_collinear_contours_ext_xldunion_collinear_contours_ext_xldUnionCollinearContoursExtXldUnionCollinearContoursExtXld, union_cocircular_contours_xldunion_cocircular_contours_xldunion_cocircular_contours_xldUnionCocircularContoursXldUnionCocircularContoursXld, union_straight_contours_xldunion_straight_contours_xldunion_straight_contours_xldUnionStraightContoursXldUnionStraightContoursXld, union_cotangential_contours_xldunion_cotangential_contours_xldunion_cotangential_contours_xldUnionCotangentialContoursXldUnionCotangentialContoursXld

See also

edges_sub_pixedges_sub_pixedges_sub_pixEdgesSubPixEdgesSubPix, threshold_sub_pixthreshold_sub_pixthreshold_sub_pixThresholdSubPixThresholdSubPix, gen_polygons_xldgen_polygons_xldgen_polygons_xldGenPolygonsXldGenPolygonsXld, split_contours_xldsplit_contours_xldsplit_contours_xldSplitContoursXldSplitContoursXld, select_contours_xldselect_contours_xldselect_contours_xldSelectContoursXldSelectContoursXld, get_contour_xldget_contour_xldget_contour_xldGetContourXldGetContourXld, get_contour_attrib_xldget_contour_attrib_xldget_contour_attrib_xldGetContourAttribXldGetContourAttribXld

Module

Foundation