grey_skeleton__ ( Image : GreySkeleton : : )

Thinning of gray value images.

grey_skeleton__ applies a gray value thinning operation to the input image Image. Figuratively, the gray value ``mountain range'' is reduced to its ridge lines by setting the gray value of ``hillsides'' to the gray value at the corresponding valley bottom. The resulting ridge lines are at most two pixels wide. This operator is especially useful for thinning edge images, and is thus an alternative to nonmax_suppression_amp. In contrast to nonmax_suppression_amp, grey_skeleton__ preserves contours, but is much slower. In contrast to skeleton, this operator changes the gray values of an image while leaving its region unchanged.


Parameters

Image (input_object)
image(-array) -> object
Image to be thinned.

GreySkeleton (output_object)
image(-array) -> object
Thinned image.


Example
/* Seeking leafs of a beech tree in an aerial picture: */
read_image(:Image:'wald1':) >
grey_skeleton__(Image:Skelett::) >
mean__(Skelett:MeanSkelett:7,7:) >
dyn_threshold__(Skelett,MeanSkelett:Leafs:3,'light':).

Result

grey_skeleton__ returns TRUE if all parameters are correct. If the input is empty the behaviour can be set via set_system(::'no_object_result',<Result>:). If necessary, an exception is raised.


Possible Successors

mean__


Alternatives

nonmax_suppression_amp, nonmax_suppression_dir, local_max


See also

skeleton, max1__



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