Provided by: radiance_4R1+20120125-1.1_amd64 bug

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 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       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.  Interleaving 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 PRIMARIES 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  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.

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)