NAME¶
vdist3d - perform a 3D distance transform
SYNOPSIS¶
vdist3d [-option ...] [infile]
[outfile ]
DESCRIPTION¶
vdist3d performs a 3D distance transform on the
source image to
produce a file of a distance transformed
destination image. Each pixel
in the output image contains the distance to the nearest feature element
measured in a Euclidean or Chamfer metric. If needed, three images containing
the addresses of the nearest foreground pixels will also be produced.
The input image must be of type VBit. The output image will be of type VFloat.
If present, the vector images will be of type VShort.
Input and output files can be specified on the command line or allowed to
default to stdin and stdout.
If the metric is
euclidean, and no vectors are needed, the algorithm used
is Saito/Toriwaki's algorithm. If the metric is
euclidean, but vectors
are needed, then Daniellson's algorithm is used. For the chamfer metric the
algorithm by Borgefors is used. Note that Daniellson's algorithm is the most
expensive (both w.r.t computing time as well as w.r.t space). The second most
expensive algorithm is Saito/Toriwaki's. However, it is not possible to obtain
the distance vectors from this algorithm. The cheapest is Borgefors's, which
also does not yield the distance vectors.
Note that in some rare cases, Daniellson's algorithm fails. In that case, use
Saito's algorithm (which always works) and do without the distance vectors.
LITERATURE¶
Toyofumi Saito, Jun-Ichiro Toriwaki, New algorithms for euclidean distance
transformation of a n-dimensional picture with applications, Pattern
Recognition, Vol. 27, No. 11, pp 1551-1565, 1994.
Gunilla Borgefors, "Distance Transformations in Arbitrary Dimensions",
Computer Vision, Graphics and Image Processing, Vol 27, pp. 321-345, 1984.
P.-E. Daniellson, "Euclidean Distance Mapping", Computer Graphics and
IMage Processing, Vol. 14, pp. 227-248, 1980.
COMMAND LINE OPTIONS¶
vdist3d accepts the following options in any order:
- -help
- Causes vdist3d to print out a message describing its
options.
- -metric euclidean/chamfer
- Determines which metric to use.
- -vector yes/no
- Determines whether or not a vector image will be produced.
Default: no.
SEE ALSO¶
Vista(7Vi)
AUTHOR¶
Gabriele Lohmann <lohmann@cns.mpg.de>