Ubuntu Manpage: jbgtopbm - JBIG1 to portable bitmap file converter

Provided by: jbigkit-bin_2.1-6.1ubuntu1_amd64

NAME

       jbgtopbm - JBIG1 to portable bitmap file converter

SYNOPSIS

       jbgtopbm [ options ] [ input-file | -  [ output-file ]]

DESCRIPTION

       Reads  in  a JBIG1 bi-level image entity (BIE) from a file or standard input, decompresses
       it, and outputs a portable bitmap (PBM) file.

       JBIG1 is a highly effective lossless compression algorithm for bi-level  images  (one  bit
       per pixel), which is particularly suitable for scanned document pages.

       A  JBIG1  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. With option -m the input file can consist of multiple
       concatenated BIEs which contain different increasing resolution layers of the same image.

       If  more  than  one  bit  per  pixel  is stored in the JBIG1 file, then a PGM file will be
       produced.

OPTIONS

- A single hyphen instead of an input file name will cause jbgtopbm 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 satisfies both limits will be selected.

-m Process multiple concatenated BIEs. If there are bytes left after the final
SDE in the first BIE, then with this option jbgtopbm will attempt to decode
these as the start of another BIE that may contain higher resolution data.
Normally, any remaining bytes will generate a warning message.

-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 bitplane and a PGM output file is produced. 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 single BIE. With this option, jbgtopbm will print a summary of
the header information found in the input file, followed by a list of all
PSCD and ESC marker sequences encountered until the end of the file is
reached.

-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.

BUGS

       Using standard input and standard output for binary data works only on systems where there
       is no difference between binary and text streams (e.g., Unix). On other systems (e.g., MS-
       DOS),  using  standard input or standard output may cause control characters like CR or LF
       to be inserted or deleted and this will damage the binary data.

STANDARDS

       This program  implements  the  JBIG1  image  coding  algorithm  as  specified  in  ISO/IEC
       11544:1993 and ITU-T T.82(1993).

AUTHOR

       The  jbgtopbm  program is part of the JBIG-KIT package, which has been developed by Markus
       Kuhn.  The most recent version of this portable JBIG1 library and tools set  is  available
       from <http://www.cl.cam.ac.uk/~mgk25/jbigkit/>.