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diff --git a/converter/other/jbig/ANNOUNCE b/converter/other/jbig/ANNOUNCE new file mode 100644 index 00000000..edbcc3f8 --- /dev/null +++ b/converter/other/jbig/ANNOUNCE @@ -0,0 +1,243 @@ + +Version 1.2 of the JBIG-KIT lossless image compression library available +------------------------------------------------------------------------ + +Markus Kuhn -- 2000-04-08 + + +The latest release of JBIG-KIT can be downloaded over the Internet +with anonymous ftp from + + ftp://ftp.informatik.uni-erlangen.de/pub/doc/ISO/JBIG/jbigkit-1.2.tar.gz + http://www.cl.cam.ac.uk/~mgk25/download/jbigkit-1.2.tar.gz + +and from a number of other servers. + +JBIG-KIT implements a highly effective data compression algorithm for +bi-level high-resolution images such as fax pages or scanned +documents. + +JBIG-KIT provides a portable library of compression and decompression +functions with a documented interface that you can very easily include +into your image or document processing software. In addition, JBIG-KIT +provides ready-to-use compression and decompression programs with a +simple command line interface (similar to the converters found in Jef +Poskanzer's PBM graphics file conversion package). + +JBIG-KIT implements the specification + + International Standard ISO/IEC 11544:1993 and ITU-T Recommendation + T.82(1993), "Information technology - Coded representation of picture + and audio information - progressive bi-level image compression", + <http://www.itu.ch/itudoc/itu-t/rec/t/t82_23822.html>, + +which is commonly referred to as the "JBIG standard". JBIG (Joint +Bi-level Image experts Group) is the committee which developed this +international standard for the lossless compression of images using +arithmetic coding. Like the well-known compression algorithms JPEG and +MPEG, also JBIG has been developed and published by the International +Organization for Standardization (ISO) and the International +Telecommunication Union (ITU). See also + + http://www.jpeg.org/public/jbighomepage.htm + http://www.iso.ch/ + http://www.itu.ch/ + +The JBIG compression algorithm offers the following features: + + - Close to state-of-the-art lossless compression ratio for high + resolution bi-level images. + + - Around 1.1 to 1.5 times better compression ratio on typical + scanned documents compared to G4 fax compression (ITU-T T.6), + which has been the best compression algorithm for scanned + documents available prior to JBIG. + + - Up to 30 times better compression of scanned images with dithered + images compared to G4 fax compression. + + - Around 2 times better compression on typical 300 dpi documents + compared to 'gzip -9' on raw bitmaps. + + - Around 3-4 times better compression than GIF on typical 300 dpi + documents. + + - Even much better competitive compression results on computer + generated images which are free of scanning distortions. + + - JBIG supports hierarchical "progressive" encoding, that means it is + possible to encode a low resolution image first, followed by + resolution enhancement data. This allows for instance a document + browser to display already a good 75 dpi low resolution version of + an image, while the data necessary to reconstruct the full 300 dpi + version for laser printer reproduction is still arriving (say + over a slow network link or mass storage medium). + + - The various resolution layers of a JBIG image in progressive + encoding mode together require not much more space than a + normal non-progressive mode encoded image (which JBIG also + supports). + + - The progressive encoding mode utilizes a very sophisticated + resolution reduction algorithm which offers highest quality + low resolution versions that preserve the shape of characters as + well as the integrity of thin lines and dithered images. + + - JBIG supports multiple bit planes and can this way also be used + for greyscale and color images, although the main field of + application is compression of bi-level images, i.e. images with + only two different pixel values. For greyscale images with up to + 6 bit per pixel, JBIG performs superior to JPEG's lossless + mode. + +JBIG-KIT is free software under the GNU General Public License. For +other license arrangements contact the author. JBIG-KIT provides a +portable library implemented in ANSI/ISO C for encoding and decoding +JBIG data streams together with documentation. The library is not +intended for 8-bit or 16-bit machine architectures (e.g., old MS-DOS C +compilers) on which a number of very efficient optimization techniques +used in this software are not possible. For maximum performance, a +32-bit processor is required (64-bit systems work too, of course). On +architectures with 16-bit pointer arithmetic, only very small images +can be processed. + +Special features of the JBIG-KIT implementation are: + + - Fully reentrant multithread-capable design (no global or static + variables, isolated malloc()/free() calls, etc.). + + - Capable of handling incomplete and growing JBIG data streams in + order to allow earliest display of low resolution versions. + + - Capable of handling several incoming data streams simultaneously + in one single process and task. + + - Especially designed with applications in mind that want to display + incoming data as early as possible (e.g., similar to the way in + which Netscape Navigator handles incoming GIF images). + + - Implements all JBIG features and options including progressive and + sequential encoding, multiple bit planes, user specified + resolution reduction and deterministic prediction tables, adaptive + template changes for optimal performance on half-tone images, + deterministic prediction, typical prediction in lowest and + differential layers, various stripe orderings, etc. Only the SEQ + and HITOLO options are currently not supported by the decoder + (they are normally never required, but could be added later in + case of user requirements). + + - Efficient code, optimized utilization of 32-bit processor + registers. + + - Very easy to use documented C library interface. + + - Included Gray code conversion routines for efficient encoding + of greyscale images. + + - Ready-to-use pbmtojbg and jbgtopbm converters. + + +Changes in version 1.2 (2000-04-08): + + - bug in the decoder fixed, which caused the rest of the input file + to be skipped whenever a comment marker was encountered (special + thanks to Ben Rudiak-Gould <benrg@math.berkeley.edu> for + reporting this one) + +Changes in version 1.1 (1999-11-16): + + - serious bug in the encoder fixed, which for a very small + percentage of images has caused an unterminated linked list to be + created internally that could have been responsible for + segmentation violations or non-terminating encoders + (special thanks to Hisashi Saiga <saiga@itl.tnr.sharp.co.jp> for + tracking that one down) + + - minor bug in the "jbgtopbm -d" diagnostic output fixed + +Changes in version 1.0 (1998-04-11): + + - two bugs fixed that caused the encoder and decoder to fail + under certain modes of operation with several bit planes + + - added new functions jbg_split_planes(), jbg_dec_merge_planes(), + and jbg_dec_getsize_merged() for easy handling of greyscale + images + + - added support for compressing greyscale PGM files to pbmtojbg + and jbgtopbm + + - more changes to avoid paranoid compiler warnings + +Changes in version 0.9 (1996-01-09): + + - encoder won't break any more on input bitmap data with incorrect + zero padding + + - pbmtojbg displays a warning if input file has incorrect zero + padding + + - various minor improvements suggested by Stefan Willer + <Stefan.Willer@unnet.wupper.DE> + + - many minor changes in order to avoid warnings from paranoid + compilers + +Changes in version 0.8 (1995-09-20): + + - namespace cleared up, all names externally visible from the library + start now with jbg_ or JBG_ + + - minor non-critical bug fixed which caused library to fail compatibility + test and showed up especially on DEC Alpha systems + + - jbg_dec_gethight() is now called jbg_dec_getheight() + + - filenames conform now to MS-DOS limits + + - Bug in pbmtojbg fixed (handling of ASCII PBM files) + +Changes in version 0.7 (1995-06-10): + + - more problems on 16-bit int systems and on Macintosh systems fixed + (special thanks to Jean-Pierre Gachen <jpg11@calvanet.calvacom.fr>) + + - global Makefile + +Changes in version 0.6 (1995-06-08): + + - memory leak fixed + + - should now also work on systems where int is only 16-bit large + + - changes of the JBIG "Technical Corrigendum 1" included (special + thanks to Dr. Sebestyen from Siemens AG for sending me a copy + of the draft) + +First release: version 0.5 (1995-05-28) + + +Please send all questions, problem reports, patches, suggestions, +success stories, comments, etc. to + + mkuhn at acm.org + +I will try to provide free support and maintenance for this software +at least for the next few months depending on my available time. + +Y2K statement: JBIG-KIT does not handle any date and time related +data, therefore if JBIG-KIT causes you any problems related to date +and time overflows, this would indeed be most surprising. + +This library has been published in the hope that it will encourage the +development of good freely available scanned document handling and +transmission systems for the Internet so that large amounts of scanned +text can be made available to the global village easily. + +Happy compressing ... + +Markus Kuhn + +-- +Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK +email: mkuhn at acm.org, home page: <http://www.cl.cam.ac.uk/~mgk25/> |