UNEXP(1)UNEXP(1)NAMEunexp - Convert "exponential" files into normal files.
SYNOPSISunexp [ -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 com‐
mon exponent for the other channels. This allows the values repre‐
sented 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 "exponen‐
tial_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 exe‐
cuted, and values found exceeding the maximum are clamped.
-o outfile
If specified, the output will be written to this file. If out‐
file is "-", or if it is not specified, the output will be writ‐
ten 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 out‐
put.
-v Verbose mode, print a message to stderr after scanning or con‐
verting every hundred scanlines.
SEE ALSOfloat_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)
