jbigtopnm



Jbigtopnm User Manual(0)                              Jbigtopnm User Manual(0)




NAME

       jbigtopnm - JBIG to PNM image file converter



SYNOPSIS

       jbigtopnm [options] [input-file [output-file]]



DESCRIPTION

       This program is part of Netpbm(1).

       jbigtopnm reads a JBIG bi-level image entity (BIE) from a file or stan-
       dard 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.  You can
       use  options -x and -y 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

       -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.  You can  also  use
              options  -x and -y together which selects the largest layer that
              satisfies both limits.


       -b     Use binary values instead of Gray code words in order to  decode
              pixel  values  from  multiple bitplanes.  This option has effect
              only if the input has more  than  one  bitplane  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 only prints a  sum-
              mary  of the header information found in the input file and then
              exits.


       -p number
              If the input contains multiple bitplanes, then extract only  the
              specified  single plane as a PBM file.  The first plane has num-
              ber 0.





STANDARDS

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



AUTHOR

       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.

       jbigtopnm is part of the Netpbm package of graphics tools.



SEE ALSO

       pnm(1), pnmtojbig(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.



netpbm documentation           19 November 2003       Jbigtopnm User Manual(0)

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