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pvalue - convert RADIANCE picture to/from alternate formats
pvalue [ options ] [ file ]
Pvalue converts the pixels of a RADIANCE picture to or from
another format. In the default mode, pixels are sent to the
standard output, one per line, in the following ascii
format:
xpos ypos red green blue
If no file is given, the standard input is read.
- -u
- Print only unique values in the output, skipping
runs of equal pixels. Specifying +u turns this
option off, which is the default.
- -o
- Print original values, before exposure
compensation. Specifying +o uses final values,
which is the default.
- -h
- Do not print header. Specifying +h causes the
header to be printed, which is the default.
- -H
- Do not print the resolution string. (See also the
-r option below.) Specifying an input resolution
for reverse conversion also turns this option off.
Specifying +H causes the resolution string to be
printed, which is the default.
- -e exposure
-
Adjust the exposure by the amount specified. If
the exposure is being given as a conversion
factor, use +e instead, so an EXPOSURE line will
not be recorded in the header (if any).
- -g gamma
- Set gamma correction for conversion. When
converting from a RADIANCE picture to another
format, the inverse gamma is applied to correct
for monitor response. When converting to a
RADIANCE picture (-r option), the gamma is applied
directly to recover the linear values. By
default, gamma is set to 1.0, meaning no gamma
correction is performed.
- -d
- Data only, do not print x and y pixel position.
- -da
- Same as -d.
- -di
- Print ascii integer values from 0 to 255+. If +di
is given, the integer values will be preceded by
the x and y pixel locations.
- -db
- Print binary byte values from 0 to 255.
- -df
- Print binary float values.
- -dd
- Print binary double values.
- -R
- Reverse ordering of colors so that the output is
blue then green then red. The default ordering
(specified with +R) is red then green then blue.
- -b
- Print brightness values rather than RGB.
Specifying +b turns this option off, which is the
default.
- -r
- Perform reverse conversion. Input is in the
format given by the other options. The x and y
resolution must be specified on the command line,
unless the image file contains a Radiance
resolution string at the beginning (see -H option
above and -y option below). Specifying +r
converts from a Radiance picture to other values,
which is the default.
- -y res
- Set the output y resolution to res. If +y is
specified, then the scanlines are assumed to be in
increasing order (ie. bottom to top). The default
value for this option is 0, which means that the
picture size and scanline order must appear as the
first line after the header (if any) in the input
file. Either an upper or lower case `Y' may be
used for this option. Since Radiance files always
contain such a line, this option has no effect for
forward conversions.
- +x res
- Set the output x resolution to res. If -x is
specified, then the scanlines are assumed to be in
decreasing order (ie. right to left). The
ordering of the -y and +x options determines
whether the scanlines are sorted along x or along
y. Most Radiance pictures are sorted top to
bottom, then left to right. This corresponds to a
specification of the form "-y yres +x xres".
Either an upper or lower case `X' may be used for
this option. Like the -y option, -x options have
no effect for forward conversions.
To look at the original, unique pixels in picture:
pvalue -o -u picture | more
To convert from a 512x400 8-bit greyscale image in bottom to
top, left to right scanline ordering:
pvalue -r -db -b -h +y 400 +x 512 input.im > flipped.pic
pflip -v flipped.pic > final.pic
Greg Ward
The -r option does not work with the -u option. Also, input
pixel locations are ignored during a reverse conversion, so
this information is not used in determining the scanline
ordering or picture size.
getinfo(1), pcompos(1), pfilt(1), pflip(1), protate(1),
rpict(1), rtrace(1), rview(1)
Header and Footer
PVALUE(1) RADIANCE (11/15/93) PVALUE(1)
Page 1 (printed 7/17/96)
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