gen_contours_skeleton_xld — Convert a skeleton into XLD contours.
gen_contours_skeleton_xld converts the input skeleton
Skeleton, which is assumed to contain
mostly one pixel wide regions (see
skeleton), into XLD
The algorithm first attempts to transform the regions to contain only line
segments in 8-neighborhood. In a second step, the junction points are
labeled. After this,
gen_contours_skeleton_xld tries to generate
contours which end in junction or end points, in particular for junction
points of the following configurations (in all four possible
1 0 1 1 0 1 1 0 0 1 0 0 0 1 0 0 1 0
0 2 0 0 2 0 0 2 1 0 2 1 0 2 1 1 2 1
0 0 1 1 0 1 0 1 0 1 0 0 0 1 0 0 1 0
where 0 = background, 1 = foreground, and 2 = junction point.
After this, all contours having at least
Since contours are split at junction points, possibly long contours
may be split into several short segments because of short adjacent
lines, even if they are longer than
Length points, if
Mode = 'filter' was selected. This can be avoided by setting
Mode = 'generalize1'. In this case, the contours are
generated as if the segments shorter than
Length were not
contained in the input region. In order to preserve line segments,
which are split into very short segments by the crossing of short
Mode = 'generalize2' can be selected. In this
case, line segments are preserved if they end in two junction
points, even if they are shorter than
Skeleton of which the contours are to be determined.
Minimum number of points a contour has to have.
Default value: 1
Suggested values: 1, 2, 3, 5, 10, 20
Contour filter mode.
Default value: 'filter'
List of values: 'filter', 'generalize1', 'generalize2'