JBIGTOPNM(1)JBIGTOPNM(1)NAMEjbigtopnm - JBIG to PNM image file converter
SYNOPSISjbigtopnm [ options ] [ input-file | - [ output-file ]]
DESCRIPTION
Reads in a JBIG bi-level image entity (BIE) from a file or
standard input, decompresses it, and outputs a PBM or PGM
file. If the input has one plane, or you choose just one
plane of it, the output is PBM. Otherwise, the output is
PGM.
JBIG is a highly effective lossless compression algorithm
for bi-level images (one bit per pixel), which is particu
larly suitable for scanned document pages.
A JBIG encoded image can be stored in several resolutions
in one or several BIEs. All resolution layers except the
lowest one are stored efficiently as differences to the
next lower resolution layer. Options -x and -y can be used
to stop the decompression at a specified maximal output
image size. The input file can consist of several concate
nated BIEs which contain different increasing resolution
layers of the same image.
OPTIONS
- A single hyphen instead of an input file
name will cause jbigtopnm to read the data
from standard input instead from a file.
-x number Decode only up to the largest resolution
layer which is still not more than number
pixels wide. If no such resolution layer
exists, then use the smallest one available.
-y number Decode only up to the largest resolution
layer which is still not more than number
pixels high. If no such resolution layer
exists, then use the smallest one available.
Options -x and -y can also be used together
in which case the largest layer that satis
fies both limits will be selected.
-b Use binary values instead of Gray code words
in order to decode pixel values from multi
ple bitplanes. This option has only an
effect if the input has more than one bit
plane and you don't select just one of those
bitplanes. Note that the decoder has to be
used in the same mode as the encoder and
cannot determine from the BIE, whether Gray
or binary code words were used by the
encoder.
-d Diagnose a BIE. With this option, jbigtopnm
will only print a summary of the header
information found in the input file and then
exit.
-p number If the input contains multiple bitplanes,
then extract only the specified single plane
as a PBM file. The first plane has number 0.
STANDARDS
This program implements the JBIG image coding algorithm as
specified in ISO/IEC 11544:1993 and ITU-T T.82(1993).
AUTHOR
The jbigtopnm is based on the JBIG library by Markus Kuhn,
part of his JBIG-KIT package. The jbgtopbm program is
part of the JBIG-KIT package. The most recent version of
that library and tools set is freely available on the
Internet from anonymous ftp server ftp.informatik.uni-
erlangen.de in directory pub/doc/ISO/JBIG/.
jbigtopnm is part of the Netpbm package of graphics tools.
SEE ALSOpbm(5),pgm(5),pbmtojbg(1)LICENSE
If you use jbigtopnm, you are using various patents, par
ticularly on its arithmetic encoding method, and in all
probability you do not have a license from the patent own
ers to do so.
2000-05-20 JBIGTOPNM(1)
