
vlpf(1)                      Khoros                       vlpf(1)

PROGRAM
     vlpf - Perform a low-pass filtering operation on an image in
     the frequency domain.

SYNTAX
     vlpf

     -i             first input image

     -o             resulting output image

     -n             selects the order of the filter

     -c             selects the cut off radius

     [-t]           Choose Exponential Filter [False] or Butter-
                    worth Filter [True]

     [-V]           Gives the version for vlpf

     [-U]           Gives the usage for vlpf

     [-P]           Prompts for command line options

     [-A [file1]]   Creates the answer file called vlpf.ans or
                    file1

     [-a [file1]]   Uses vlpf.ans or file1 as the answer file

DESCRIPTION
     vlpf performs a low-pass filtering operation on an image in
     the frequency domain. The filter cutoff is a radius normal-
     ized to the longest image dimension (lets you filter non-
     square images, but with an elliptical cutoff area). The
     order of the filter is an integer specifying the sharpness
     of the cutoff.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: first input image

     -o     type: outfile
            desc: resulting output image

     -n     type: integer
            desc: selects the order of the filter

     -c     type: float
            desc: selects the cut off radius

OPTIONAL ARGUMENTS
     -t     type: boolean
            desc: Choose Exponential Filter [False] or Butter-
            worth Filter [True]
            default: false

EXAMPLES
     vlpf -i input.image -o output.image -n 1 -c 1 -t 0

     This command low pass filters input.image and stores the
     result in output.image.  The order of the filter is 1 and
     the cutoff radius is 1.  An exponential filter is used.

SEE ALSO
     intro(1), verror(3), vgparms(3), vutils(3), lvlpf(3)

RESTRICTIONS
     vlpf will complain if asked to operate on non COMPLEX data
     storage type images.

     Filters of high order can take a long time to do their work.

COPYRIGHT
     Copyright 1991, University of New Mexico.  All rights
     reserved.

Khoros                    Release: 1.0                          1

