Radiance pvalue program

PVALUE(1)                                                            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 cor-
                 respond to units of  candelas/meter^2.   Otherwise,  the  RGB
                 values should be in spectral watts/steradian/meter^2.  Speci-
                 fying +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  conver-
                 sion  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 for-
                 eign 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 Radi-
                 ance 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. bot-
                 tom 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 deter-
                 mines 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),   rpict(1),
       rtrace(1), rvu(1)

RADIANCE                            1/15/99                          PVALUE(1)