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 particularly 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 concatenated
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 reso‐
lution 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 reso‐
lution layer exists, then use the smallest one available.
Options -x and -y can also be used together in which case
the largest layer that satisfies both limits will be
selected.
-b Use binary values instead of Gray code words in order to
decode pixel values from multiple 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 pack‐
age. 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, particularly on
its arithmetic encoding method, and in all probability you do not have
a license from the patent owners to do so.
2000-05-20 JBIGTOPNM(1)
