gen_contour_region_xldgen_contour_region_xldGenContourRegionXldGenContourRegionXldGenContourRegionXldgen_contour_region_xld generates XLD contours
ContoursContoursContoursContourscontourscontours from the regions given in 区域区域区域区域区域区域. This
operator is useful if regions have been obtained from segmentation
operations, but higher level operators, e.g., polygon approximation
and extraction of parallels, are to be performed on their
boundaries. For each connected component of the input regions a
closed contour of the boundary is generated. The parameter
ModeModeModeModemodemode can take on the following values:
'center'"center""center""center""center""center": The centers of the border pixels are used
as contour points.
'border'"border""border""border""border""border": The outer border of the border pixels is
used as contour points.
'border_holes'"border_holes""border_holes""border_holes""border_holes""border_holes": In addition to the outer border of the
input region you get the contours of all holes.
The difference between the modes is demonstrated using the
following region:
Example region.
Computing the contour with the different values available for
ModeModeModeModemodemode returns the following result contours:
(
1)
(
2)
(
3)
Result for 'center'"center""center""center""center""center" (1), 'border'"border""border""border""border""border" (2), and
'border_holes'"border_holes""border_holes""border_holes""border_holes""border_holes" mode (3).
This means, for example, that contours generated with
'border'"border""border""border""border""border" will in general have a much larger Euclidean
length (see length_xldlength_xldLengthXldLengthXldLengthXldlength_xld) than contours generated with
'center'"center""center""center""center""center". This results from the fact that for diagonal
border elements 'border'"border""border""border""border""border" uses two contour segments of
length 1 each, whereas 'center'"center""center""center""center""center" uses a single segment of
length . Other features, e.g., the area (see
area_center_xldarea_center_xldAreaCenterXldAreaCenterXldAreaCenterXldarea_center_xld), will obviously also have different values.
运行信息
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
List of values:
'border'"border""border""border""border""border", 'border_holes'"border_holes""border_holes""border_holes""border_holes""border_holes", 'center'"center""center""center""center""center"