PVALUE(1)						      General Commands Manual							 PVALUE(1)

NAME

       pvalue - convert RADIANCE picture to/from alternate formats

SYNOPSIS

       pvalue [ options ] [ file ]
       pvalue -r [ options ] [ file1 [ file2 file3 ] ]

DESCRIPTION

       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.

       The reverse conversion option (-r) may be used with a single input file or when reading from the standard input, but if the second form	is
       used with three separate input files, the three primaries are presumed to be separated in these files.

       -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.  If the input file is in XYZE format, the Y (green) channel will	correspond
		 to units of candelas/meter^2.	Otherwise, the RGB values should be in spectral watts/steradian/meter^2.  Specifying +o uses final
		 exposed 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.

       -s nbytes Skip  the  specified  number  of bytes on the input header.  This option is useful for skipping unintelligible headers in foreign
		 file formats.	(Does not work when reading from standard input.)

       -e exposure
		 Adjust the exposure by the amount specified.  If the exposure is being given as a conversion factor, use +e instead, so an  EXPO-
		 SURE 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	 Output binary byte values from 0 to 255.

       -dw	 Output binary 16-bit words from 0 to 65535.

       -dW	 Output binary 16-bit words from 0 to 65535, byte-swapped.

       -df	 Output binary float values.

       -dF	 Output byte-swapped binary float values.

       -dd	 Output binary double values.

       -dD	 Output byte-swapped 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.

       -n	 The RGB values are non-interleaved, meaning that all the red, green and blue data are stored together in separate chunks.  Inter-
		 leaving may be turned on with the +n option, which is the default.

       -b	 Print brightness values rather than RGB.  Specifying +b turns this option off, which is the default.

       -pP	 Put  out  only  the  primary P, where P is one of upper or lower case 'R', 'G' or 'B' for red, green or blue, respectively.  This
		 option may be used to separate the Radiance primaries into three files with three separate runs of pvalue, or only one file  when
		 only one primary is needed.  Note that there is no space between this option and its argument.

       -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.

       -p xr yr xg yg xb yb xw yw
		 On  reverse  conversion, RGB input uses the given set of color primaries.  These are written into the output header with the PRI-
		 MARIES variable.

       -pXYZ	 On reverse conversion, input is in CIE XYZ coordinates, rather than RGB.  The Y channel is assumed to be in candelas/meter^2.

       -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 pic-
		 tures	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.

EXAMPLE

       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.hdr
	 pflip -v flipped.hdr > final.hdr

AUTHOR

       Greg Ward

BUGS

       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.

SEE ALSO

       getinfo(1), pcompos(1), pfilt(1), pflip(1), protate(1), ra_xyze(1), rpict(1), rtrace(1), rvu(1)

RADIANCE
							      1/15/99								 PVALUE(1)