jbigtopnm(1) - phpMan

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 standard input, decom-
presses 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 res-
olution 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 avail-
able.

-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 avail-
able. 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 summary 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 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
jbigtopnm is based on the JBIG library by Markus Kuhn, part of his JBIG-KIT package
<http://www.cl.cam.ac.uk/~mgk25/jbigkit/> . The jbgtopbm program is part of the JBIG-KIT
package.

jbigtopnm is part of the Netpbm package of graphics tools.