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 identify 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.