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ra_t8 (1)
NAME
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ra_t8 - convert RADIANCE picture to/from Targa 8-bit image file |
SYNOPSIS
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ra_t8 [ -d ][ -b ][ -c ncolors
][ -g gamma ][ -e +/-stops ][ -n
sampfac ] input [ output ]
ra_t8 -r [ -g gamma ][ -e +/-stops ] [
input [ output ] ] |
DESCRIPTION
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Ra_t8 converts between RADIANCE and Targa 8-bit
color-mapped image files (type 1 in Targa's documentation).
In the default mode, a RADIANCE picture is converted to a
color-mapped Targa file of the same horizontal and vertical
dimensions with 8-bits per pixel. The -d option turns
off dithering. The -b option converts the image to
black and white. Only with this option can the input be
taken from stdin. The -c option allows fewer than 256
colors. The -g option specifies the exponent used in
gamma correction; the default value is 2.2. An exponent of
1.0 turns gamma correction off. The -e option
specifies an exposure compensation in f-stops (powers of
two). Only integer stops are allowed, for efficiency. The
-n option specifies a sampling factor for neural
network color quantization. This value should be between 1
and 80, where 1 takes the longest and produces the best
results in small areas of the image. If no value is given, a
faster median cut algorithm is used. The -r option
invokes a reverse conversion, from an 8-bit Targa file to a
RADIANCE picture. If the output file is missing, the
standard output is used. |
AUTHORS
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Greg Ward
Anthony Dekker provided the code for neural network color
quantization |
BUGS
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Run-length encoded files can be read but not written with
this program. |
SEE ALSO
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