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UNEXP(1)               DragonFly General Commands Manual              UNEXP(1)


NAME

       unexp - Convert "exponential" files into normal files.


SYNOPSIS

       unexp [ -m maxval ] [ -o outfile ] [ -p ] [ -s ] [ -v ] infile


DESCRIPTION

       Unexp Converts a file of "exponential" floating point values into an
       RLE(5) file containing integer valued bytes.  Exponential files have
       N-1 channels of eight bit data, with the Nth channel containing a
       common exponent for the other channels.  This allows the values
       represented by the pixels to have a wider dynamic range.

       If no maximum value is specified, unexp first reads the RLE file to
       find the dynamic range of the whole file.  It then rewinds the file and
       scales the output to fit within that dynamic range.  If a maximum value
       is specified, unexp runs in one pass, and clamps any values exceeding
       the maximum.

       Files containing exponential data are expected to have a
       "exponential_data" comment; unexp prints a warning if such a comment
       doesn't exist.  An exponential file should be unexp'ed before
       attempting to use any tools that perform arithmetic on pixels (e.g.,
       rlecomp(1), avg4(1), fant(1), or applymap(1)) or displaying the image.

       Unexp does not allow piped input.  The infile must be a real file; the
       special filenames described in urt(1) are not allowed.  ("-" does work,
       as long as the input is coming from a real file; this is of minimal
       utility, therefore, as typing unexp - <foo.rle is harder than typing
       unexp foo.rle.)


OPTIONS

       -m maxval
              Specify the maximum value (i.e., the data in the file is assumed
              to be in the range 0..maxval).  Only the conversion pass is
              executed, and values found exceeding the maximum are clamped.

       -o outfile
              If specified, the output will be written to this file.  If
              outfile is "-", or if it is not specified, the output will be
              written to the standard output stream.

       -p     Print the maximum value found during the scanning phase

       -s     Just scan the file to find the maximum, don't generate any
              output.

       -v     Verbose mode, print a message to stderr after scanning or
              converting every hundred scanlines.


SEE ALSO

       float_to_exp(3), urt(1), RLE(5).


AUTHOR

       John W. Peterson


BUGS

       Unexp is provided because of the lack of floating point or extended
       precision RLE files.

       The -v flag is a historical relict from the slow CPU days.

4th Berkeley Distribution      November 8, 1987                       UNEXP(1)

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