
vsub(1)                      Khoros                       vsub(1)

PROGRAM
     vsub - Compute the difference (subtract) between two images
     pixel by pixel.

SYNTAX
     vsub

     -i1            first input image

     -i2            second input image

     -o             resulting output image

     [-m]           subtraction operation masking image

     [-V]           Gives the version for vsub

     [-U]           Gives the usage for vsub

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     vsub computes the difference between the first input image
     and the second input image (result = image1 - image2), with
     an optional operation gating image.

     The two input images must be of the same size and have the
     same number of data bands, as must the optional mask image.
     The input images may be of the same or different data types.
     If the input images are of different data types, then all
     input images will be upcast to the highest input image data
     type.  The output image data type will be the same as that
     of the highest data type of the input images.

     The optional mask (gating) image will be upcast to the
     highest data type of the input images.  The mask image is
     used to gate the operation.  A non-zero mask pixel enables
     the output pixel to contain the result of the division. A
     zero mask pixel just transfers the value of the correspond-
     ing pixel in the first input image to the output pixel.

REQUIRED ARGUMENTS
     -i1    type: infile
            desc: first input image

     -i2    type: infile
            desc: second input image

     -o     type: outfile
            desc: resulting output image

OPTIONAL ARGUMENTS
     -m     type: infile
            desc: subtraction operation masking image

EXAMPLES
     vsub -i1 input.image1 -i2 input.image2 -o output.image -m
     mask.image

     This subtracts input.image2 from input.image1 using a mask
     image and stores the results in output.image.

SEE ALSO
     intro(1), verror(3), vgparms(3), vutils(3), lvsub(3)
     vcast(1)

RESTRICTIONS
     vsub will not operate on:
          Bit
     data storage types.

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

Khoros                    Release: 1.0                          1

