tiffdither
convert a greyscale image to bilevel using dithering
see also :
pal2rgb - fax2tiff - tiffinfo - tiffcp - tiff2bw
Synopsis
tiffdither
[ options ] input.tif output.tif
add an example, a script, a trick and tips
examples
no example yet ...
... Feel free to add your own example above to help other Linux-lovers !
description
tiffdither
converts a single channel 8-bit greyscale image to a bilevel
image using Floyd-Steinberg error propagation with
thresholding.
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,
zip for Deflate compression, g3 for CCITT
Group 3 (T.4) compression, and g4 for CCITT Group 4
(T.6) compression. By default tiffdither will
compress data according to the value of the
Compression tag found in the source file.
The
CCITT Group 3 and Group 4 compression
algorithms can only be used with bilevel data.
Group 3
compression can be specified together with several
T.4-specific options: 1d for 1-dimensional encoding,
2d for 2-dimensional encoding, and fill to
force each encoded scanline to be zero-filled so that the
terminating EOL code lies on a byte boundary. Group
3-specific options are specified by appending a
’’:’’-separated list to the
’’g3’’ option; e.g. -c
g3:2d:fill to get 2D-encoded data with byte-aligned EOL
codes.
LZW
compression can be specified together with a
predictor value. A predictor value of 2 causes each
scanline of the output image to undergo horizontal
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.
-f
Specify the bit fill order to
use in writing output data. By default, tiffdither
will create a new file with the same fill order as the
original. Specifying -f lsb2msb will force data
to be written with the FillOrder tag set to
LSB2MSB , while -f msb2lsb will
force data to be written with the FillOrder tag set
to MSB2LSB .
-t
Set the threshold value for dithering. By default the
threshold value is 128.
notes
The dither algorithm is taken from the tiffmedian(1)
program (written by Paul Heckbert).
see also
pal2rgb ,
fax2tiff , tiffinfo , tiffcp ,
tiff2bw , libtiff(3TIFF)
Libtiff library
home page: http://www.remotesensing.org/libtiff/