UNEXP(1) 1 (November 8, 1987) 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.
Page 1 (printed 12/1/98)
UNEXP(1) 1 (November 8, 1987) UNEXP(1)-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.
Page 2 (printed 12/1/98)
