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ra_rgbe (1)
NAME
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ra_rgbe - convert between different RADIANCE picture types |
SYNOPSIS
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ra_rgbe [ -r ][ -e +/-stops ][
-f ][ -n frameno ] [ input [
outspec ] ] |
DESCRIPTION
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Ra_rgbe converts between RADIANCE run-length encoded
and flat formats, and separates concatanated animation
frames produced by rpict(1). The -e option
specifies an exposure compensation in f-stops (powers of
two). Only integer stops are allowed, for efficiency. By
default, ra_rgbe produces a flat RADIANCE picture
file from any type of RADIANCE input picture. The -r
option causes ra_rgbe to produce a run-length encoded
file instead. |
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If the input file consists of multiple animation frames as
produced by rpict with the -S option,
ra_rgbe will read each frame and write it to the
output file created by calling printf(3) with the
output specification and frame number as arguments. If the
output specification begins with an exclamation mark ('!'),
then this interpreted as a command spec., which is also run
through printf with the frame number to get the final
command. This command must accept a Radiance picture on its
standard input, and may write results either to a file or to
the standard output. The -n option may be used to
select a specific frame for output, and other frames in the
input will be skipped. Normally, all frames will be read and
written. |
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Ra_rgbe will report an error and exit if the target
output file already exists, unless the -f option is
given. If the output file is missing, the standard output is
used. If the input file is missing or set to '-', the
standard input is used. |
NOTES
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The file format for RADIANCE pictures was changed between
release 1.4 and release 2.0. The older format can still be
read by all the programs, but only the newer format is
produced. This newer format cannot be read by RADIANCE
software prior to release 2.0. |
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Ra_rgbe provides some downward compatibility by
producing files that can be read by older RADIANCE software.
The resultant files are also easier to manipulate with
programs designed to read raw raster data. |
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The other use for ra_rgbe is as a quicker way to
adjust the exposure of a RADIANCE picture than
pfilt(1), since ra_rgbe only allows integer
f-stop changes. In this mode, ra_rgbe should be used
with the -r option. |
AUTHOR
ACKNOWLEDGEMENT
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Work on this program was initiated and sponsored by the LESO
group at EPFL in Switzerland. |
SEE ALSO
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