1JBGTOPBM(1) General Commands Manual JBGTOPBM(1)
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6 jbgtopbm - JBIG1 to portable bitmap file converter
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9 jbgtopbm [ options ] [ input-file | - [ output-file ]]
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12 Reads in a JBIG1 bi-level image entity (BIE) from a file or standard
13 input, decompresses it, and outputs a portable bitmap (PBM) file.
14 JBIG1 is a highly effective lossless compression algorithm for bi-level
16 images (one bit per pixel), which is particularly suitable for scanned
17 document pages.
18 A JBIG1 encoded image can be stored in several resolutions in one or
20 several BIEs. All resolution layers except the lowest one are stored
21 efficiently as differences to the next lower resolution layer. Options
22 -x and -y can be used to stop the decompression at a specified maximal
23 output image size. With option -m the input file can consist of multi‐
24 ple concatenated BIEs which contain different increasing resolution
25 layers of the same image.
26 If more than one bit per pixel is stored in the JBIG1 file, then a PGM
28 file will be produced.
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31 - A single hyphen instead of an input file name will cause
32 jbgtopbm to read the data from standard input instead
33 from a file.
34 -x number Decode only up to the largest resolution layer which is
36 still not more than number pixels wide. If no such reso‐
37 lution layer exists, then use the smallest one available.
38 -y number Decode only up to the largest resolution layer which is
40 still not more than number pixels high. If no such reso‐
41 lution layer exists, then use the smallest one available.
42 Options -x and -y can also be used together in which case
43 the largest layer that satisfies both limits will be
44 selected.
45 -m Process multiple concatenated BIEs. If there are bytes
47 left after the final SDE in the first BIE, then with this
48 option jbgtopbm will attempt to decode these as the start
49 of another BIE that may contain higher resolution data.
50 Normally, any remaining bytes will generate a warning
51 message.
52 -b Use binary values instead of Gray code words in order to
54 decode pixel values from multiple bitplanes. This option
55 has only an effect if the input has more than one bit‐
56 plane and a PGM output file is produced. Note that the
57 decoder has to be used in the same mode as the encoder
58 and cannot determine from the BIE, whether Gray or binary
59 code words were used by the encoder.
60 -d Diagnose a single BIE. With this option, jbgtopbm will
62 print a summary of the header information found in the
63 input file, followed by a list of all PSCD and ESC marker
64 sequences encountered until the end of the file is
65 reached.
66 -p number If the input contains multiple bitplanes, then extract
68 only the specified single plane as a PBM file. The first
69 plane has number 0.
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72 Using standard input and standard output for binary data works only on
73 systems where there is no difference between binary and text streams
74 (e.g., Unix). On other systems (e.g., MS-DOS), using standard input or
75 standard output may cause control characters like CR or LF to be
76 inserted or deleted and this will damage the binary data.
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79 This program implements the JBIG1 image coding algorithm as specified
80 in ISO/IEC 11544:1993 and ITU-T T.82(1993).
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83 The jbgtopbm program is part of the JBIG-KIT package, which has been
84 developed by Markus Kuhn. The most recent version of this portable
85 JBIG1 library and tools set is available from
86 <http://www.cl.cam.ac.uk/~mgk25/jbigkit/>.
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89 pbm(5), pgm(5), pbmtojbg(1)
90 2003-06-04 JBGTOPBM(1)