
vgamth(1)                    Khoros                     vgamth(1)

PROGRAM
     vgamth - Generate a binary image by thresholding a color
     image.

SYNTAX
     vgamth

     -i             input image

     -o             resulting image

     -b             high threshold for map column #1

     -c             low threshold for map column #1

     -d             high threshold for map column #2

     -e             low threshold for map column #2

     -f             high threshold for map column #3

     -g             low threshold for map column #3

     -v             non-zero output value

     [-V]           Gives the version for vgamth

     [-U]           Gives the usage for vgamth

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     vgamth generates a binary image by thresholding a psuedo
     color input image.  The result image is of data type BYTE,
     and the input image must also be of type BYTE.

     The output pixel is given the specified value if:  1) only
     the lower value option is given and the pixel value is
     larger then the lower threshold, 2) only the upper value
     option is given and the pixel value is less than the upper
     threshold, 3) the upper value and lower value options are
     given and the pixel value is between the upper and lower
     threshold, or 4) same as 3 but both thresholds are equal and
     the pixel value is same as the threshold level.  Otherwise,
     the output pixel is given a zero value.

     The input image must contain a map with three columns The
     thresholding is actually performed on the maps; thus the
     input image must have a map scheme of FORCE, and the map
     data type must be BYTE.

     By choosing the appropriate limits is it possible to iden-
     tify areas in an image that are above or below a certain
     value, or to isolate certain bands of intensities in each
     colormap. There are many different combinations that can be
     used to produce the results required.

     Note that this type of image is NOT a Khoros BIT image!  The
     output image is of the data type BYTE, but the only pixel
     values are 0 and non-zero.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input image

     -o     type: outfile
            desc: resulting image

     -b     type: integer
            desc: high threshold for map column #1

     -c     type: integer
            desc: low threshold for map column #1

     -d     type: integer
            desc: high threshold for map column #2

     -e     type: integer
            desc: low threshold for map column #2

     -f     type: integer
            desc: high threshold for map column #3

     -g     type: integer
            desc: low threshold for map column #3

     -v     type: integer
            desc: non-zero output value

OPTIONAL ARGUMENTS
     none

EXAMPLES
     vgamth -i input.image -o output.image -b 125 -c 75 -d 125 -e
     75 -f 125 -g 75 -v 100

     This command performs a threshold on input.image and stores
     the result in output.image.  All pixel values between 75 and
     125 are given the value 100 in the output image.  All pixel
     values that do not fall within this range are give the value
     0.

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

RESTRICTIONS
     vgamth will only operate on 1 band images of data storage
     type BYTE, with the map enable FORCE, and map data type
     BYTE.

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

Khoros                    Release: 1.0                          1

