
vspeckle(1)                  Khoros                   vspeckle(1)

PROGRAM
     vspeckle - Reduce speckle noise from an image by using the
     Crimmins algorithm.

SYNTAX
     vspeckle

     -i             input image

     -o             output image

     [-n]           Iterations

     [-V]           Gives the version for vspeckle

     [-U]           Gives the usage for vspeckle

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     vspeckle reduces the "speckle" noise from an image.  It uses
     the "eight hull algorithm" developed by T. R. Crimmins to
     perform this reduction.

     The function takes one argument: n which determines how many
     times the image is to be sent through the speckle reducing
     filter.  This filter uses the complementary hulling tech-
     nique to reduce the speckle index of an image.

     Each pixel in the image is compared with all eight of its
     surrounding pixels.  The pixels above and below the pixel
     are the N-S pair, the pixels on either side are the E-W
     pair, those on the diagonals are the NW-SE and NE-SW pair.
     The image and a pair of pixels are sent to the symmetric
     hull function which in turn sends the image to the positive
     hull function and to the negative hull function.  The posi-
     tive and negative hull functions are called twice; the first
     time the neighboring pair of pixels is sent and the second
     time the complement of the pixels is sent.  The positive
     hull function replaces each "middle pixel" with the result
     of a several comparisons.  These comparison are a combina-
     tion of maximums and minimums.  The final comparison is a
     maximum for the postive hull algorithm.  The image is then
     sent to the negative hull function where the middle pixel is
     replaced with the result of more comparisons.  The final
     comparison for the negative hull algorithm is a minimum.
     The result of all these replacements has the effect of
     reducing the undesired speckle noise while preserving the
     edges of the original image.  The Geometric filter for
     speckle reduction is described in Applied Optics, Vol. 24,
     No. 10, 15 May 1985, Geometric fileter for speckle reduc-
     tion, by Thomas R Crimmins.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input image

     -o     type: outfile
            desc: output image

OPTIONAL ARGUMENTS
     -n     type: integer
            desc: Iterations
            default: 1
            bounds: 1 < [-n] < 20

EXAMPLES
     vspeckle -i image1 -o image2 -n 2

     This command sends the image through the geometric filter
     twice. Most of the speckle noise is removed from image1 and
     the result is stored in image2.

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

RESTRICTIONS
     vspeckle accepts only BYTE images.  The number of iterations
     is limited to 20.

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

Khoros                    Release: 1.0                          1

