RA_PPM(1)                                                            RA_PPM(1)



NNAAMMEE
       ra_ppm - convert RADIANCE picture to/from a Poskanzer Portable Pixmap

SSYYNNOOPPSSIISS
       rraa__ppppmm [ --rr ][ --aa ][ --bb ][ --ss mmaaxxvv ][ --gg ggaammmmaa ][ --ee ++//--ssttooppss ] [ iinnppuutt
       [ oouuttppuutt ] ]

DDEESSCCRRIIPPTTIIOONN
       _R_a___p_p_m converts between RADIANCE and Poskanzer Portable Pixmap formats.
       The  _-_g  option  specifies  the  exponent used in gamma correction; the
       default value is 2.2.  An exponent of 1  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  _-_r  option
       invokes  a reverse conversion, from a Pixmap to a RADIANCE picture.  If
       the output file is missing, the standard output is used.  If the  input
       file is missing as well, the standard input is used.

       The  _-_a  option produces a standard ASCII Pixmap representation instead
       of the default binary file.  The file is much larger and the conversion
       is  much slower, which is why this format is not normally used.  The _-_b
       option forces greyscale output.  The  _-_s  option  controls  the  output
       scale,  which  is 255 by default.  If this value is set above 255, then
       two bytes will be output for each component in binary mode.   This  may
       not  be  understood  by some PPM readers, which do not understand files
       with maximum values greater than 255.  The maximum allowed setting  for
       this parameter is 65535.

       With  the  _-_r  option,  the type of the Pixmap input file is determined
       automatically.  _R_a___p_p_m will read either  greyscale  or  color  Pixmaps,
       with any precision up to a maximum scale of 65535.

NNOOTTEESS
       The Poskanzer Portable Bitmap Plus package contains translators between
       the Pixmap format and many of the dozen or so  image  file  "standards"
       that  exist.   At  the  time  of this writing, the software is free and
       available by anonymous ftp from export.lcs.mit.edu (18.30.0.238) in the
       file "contrib/pbmplus.tar.Z".

AAUUTTHHOORR
       Greg Ward

AACCKKNNOOWWLLEEDDGGEEMMEENNTT
       Work  on  this program was initiated and sponsored by the LESO group at
       EPFL in Switzerland and Silicon Graphics, Inc.

SSEEEE AALLSSOO
       pfilt(1),  ra_bmp(1),   ra_bn(1),   ra_pr(1),   ra_pr24(1),   ra_t8(1),
       ra_t16(1), ra_tiff(1), ximage(1)



RADIANCE                            2/10/99                          RA_PPM(1)
