Radiance ra_t8 program

RA_T8(1)                                                              RA_T8(1)

NAME

       ra_t8 - convert RADIANCE picture to/from Targa 8-bit image file

SYNOPSIS

       ra_t8 [ -d ][ -b ][ -c ncolors ][ -g gamma ][ -e +/-stops ][ -n sampfac
       ] input [ output ]
       ra_t8 -r [ -g gamma ][ -e +/-stops ] [ input [ output ] ]

DESCRIPTION

       Ra_t8 converts between RADIANCE  and  Targa  8-bit  color-mapped  image
       files  (type 1 in Targa's documentation).  In the default mode, a RADI-
       ANCE picture is converted to a color-mapped Targa file of the same hor-
       izontal  and  vertical dimensions with 8-bits per pixel.  The -d option
       turns off dithering.  The -b option converts the  image  to  black  and
       white.   Only  with this option can the input be taken from stdin.  The
       -c option allows fewer than 256 colors.  The -g  option  specifies  the
       exponent  used in gamma correction; the default value is 2.2.  An expo-
       nent of 1.0 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 -n option specifies a sampling factor
       for  neural network color quantization.  This value should be between 1
       and 80, where 1 takes the longest and  produces  the  best  results  in
       small  areas  of  the image.  If no value is given, a faster median cut
       algorithm is used.  The -r option invokes a reverse conversion, from an
       8-bit Targa file to a RADIANCE picture.  If the output file is missing,
       the standard output is used.

AUTHORS

       Greg Ward
       Anthony Dekker provided the code for neural network color quantization

BUGS

       Run-length encoded files can be read but not written with this program.

SEE ALSO

       pfilt(1),   ra_bmp(1),   ra_bn(1),   ra_ppm(1),  ra_pr(1),  ra_pr24(1),
       ra_t16(1), ra_tiff(1), ximage(1)

RADIANCE                            5/30/95                           RA_T8(1)