TIFFMEDIAN(1)                                       TIFFMEDIAN(1)



NAME
       tiffmedian  -  apply the median cut algorithm to data in a
       TIFF file

SYNOPSIS
       tiffmedian [ options ] input.tif output.tif

DESCRIPTION
       tiffmedian applies the median  cut  algorithm  to  an  RGB
       image  in  input.tif  to  generate a palette image that is
       written to output.tif.  The  generated  colormap  has,  by
       default, 256 entries.  The image data is quantized by map-
       ping each pixel to the closest color values  in  the  col-
       ormap.

OPTIONS
       -c     Specify  the compression to use for data written to
              the output file: none for no compression,  packbits
              for  PackBits  compression,  lzw  for  Lempel-Ziv &
              Welch compression, and zip for Deflate compression.
              By  default tiffmedian will compress data according
              to the value of the Compression tag  found  in  the
              source file.

              LZW  compression  can  be specified together with a
              predictor value.  A predictor  value  of  2  causes
              each  scanline of the output image to undergo hori-
              zontal differencing before it is encoded;  a  value
              of  1  forces  each  scanline to be encoded without
              differencing.  LZW-specific options  are  specified
              by  appending a ``:''-separated list to the ``lzw''
              option; e.g.  -c lzw:2  for  LZW  compression  with
              horizontal differencing.

       -C     Specify  the number of entries to use in the gener-
              ated colormap.  By default all  256  entries/colors
              are used.

       -f     Apply  Floyd-Steinberg dithering before selecting a
              colormap entry.

       -r     Specify the number  of  rows  (scanlines)  in  each
              strip  of  data  written  to  the  output file.  By
              default, tiffmedian attempts to set the  rows/strip
              that  no  more than 8 kilobytes of data appear in a
              strip.

NOTES
       This program is derived from Paul Heckbert's  median  pro-
       gram.

SEE ALSO
       pal2rgb(1),     tiffinfo(1),     tiffcp(1),    tiffcmp(1),
       libtiff(3TIFF)

       Color Image Quantization for Frame  Buffer  Display,  Paul
       Heckbert, SIGGRAPH proceedings, 1982, pp. 297-307.

       Libtiff    library   home   page:   http://www.remotesens-
       ing.org/libtiff/



libtiff                  November 2, 2005           TIFFMEDIAN(1)