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diff --git a/converter/other/jbig/ANNOUNCE b/converter/other/jbig/ANNOUNCE deleted file mode 100644 index edbcc3f8..00000000 --- a/converter/other/jbig/ANNOUNCE +++ /dev/null @@ -1,243 +0,0 @@ - -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/> |