
vlog(1)                      Khoros                       vlog(1)

PROGRAM
     vlog - Compute the logarithm of an image pixel by pixel.

SYNTAX
     vlog

     -i             input image

     -o             resulting output image

     [-m]           logarithm operation masking input image

     [-n]           Choose Natural Log [False] or Log Base 10
                    [True]

     [-t]           Operate either on value [False] or value+1
                    [True]

     [-V]           Gives the version for vlog

     [-U]           Gives the usage for vlog

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     vlog

     vlog computes the logarithm of an image pixel by pixel with
     an operation gating image.

     The optional mask image must be of the same data type as the
     input image, and is used to gate the operation. A non-zero
     mask pixel causes the output pixel to contain the logarithm
     of (x). A zero mask pixel just transfers the value of the
     corresponding pixel in the input image to the output image.

     SPECIAL NOTE:  The log() function has machine-specific
     characteristics!  To fix this, -MAXFLOAT is returned if the
     argument is less than or equal to zero.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input image

     -o     type: outfile
            desc: resulting output image

OPTIONAL ARGUMENTS
     -m     type: infile
            desc: logarithm operation masking input image

     -n     type: boolean
            desc: Choose Natural Log [False] or Log Base 10
            [True]
            default: true

     -t     type: boolean
            desc: Operate either on value [False] or value+1
            [True]
            default: true

EXAMPLES
     vlog -i input.image -o output.image

     Takes the pixel-wise base 10 logarithm of input.image and
     places the result in output.image.

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

RESTRICTIONS
     vlog will not operate on:
          Complex, and Bit
     data storage types.

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

Khoros                    Release: 1.0                          1

