1、 Reference numberISO/IEC 14492:2001(E)ISO/IEC 2001INTERNATIONAL STANDARD ISO/IEC14492First edition2001-12-15Information technology Lossy/lossless coding of bi-level images Technologies de linformation Codage avec/sans perte dimages deux niveaux Adopted by INCITS (InterNational Committee for Informat
2、ion Technology Standards) as an American National Standard.Date of ANSI Approval: 8/29/02Published by American National Standards Institute,25 West 43rd Street, New York, New York 10036Copyright 2002 by Information Technology Industry Council (ITI).All rights reserved.These materials are subject to
3、copyright claims of International Standardization Organization (ISO), InternationalElectrotechnical Commission (IEC), American National Standards Institute (ANSI), and Information Technology Industry Council(ITI). Not for resale. No part of this publication may be reproduced in any form, including a
4、n electronic retrieval system, withoutthe prior written permission of ITI. All requests pertaining to this standard should be submitted to ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaISO/IEC 14492:2001(E) PDF disclaimer This PDF file may contain embedded typef
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9、stale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.ch Web www.iso.ch Printed in Switzerland ii ISO/IEC 2001 All rights reserved ISO/IEC 14492:2001(E) ISO/IEC 2001 All rights reserved iiiCONTENTSPage0 Introduction . viii0.1 Interpretation and use of the requir
10、ements viii0.1.1 Subject matter for JBIG2 coding. viii0.1.2 Relationship between segments and documents. ix0.1.3 Structure and use of segments. ix0.1.4 Internal representations ix0.1.5 Decoding results. xi0.1.6 Decoding procedures xi0.2 Lossy coding. xii0.2.1 Symbol coding. xii0.2.2 Generic coding.
11、xii0.2.3 Halftone coding xiii0.2.4 Consequences of inadequate segmentation xiii1 Scope. 12 Normative References 13 Terms and Definitions 14 Symbols and Abbreviations 34.1 Abbreviations 34.2 Symbol definitions 44.3 Operator definitions 105 Conventions. 105.1 Typographic conventions 105.2 Binary notat
12、ion . 105.3 Hexadecimal notation 115.4 Integer value syntax 115.4.1 Bit packing. 115.4.2 Multi-byte values . 115.4.3 Bit numbering 115.4.4 Signedness. 115.5 Array notation and conventions . 115.6 Image and bitmap conventions 116 Decoding Procedures 126.1 Introduction to decoding procedures 126.2 Gen
13、eric region decoding procedure 136.2.1 General description 136.2.2 Input parameters. 136.2.3 Return value. 136.2.4 Variables used in decoding. 146.2.5 Decoding using a template and arithmetic coding 146.2.6 Decoding using MMR coding. 186.3 Generic Refinement Region Decoding Procedure. 196.3.1 Genera
14、l description 196.3.2 Input parameters. 196.3.3 Return value. 196.3.4 Variables used in decoding. 206.3.5 Decoding using a template and arithmetic coding 20ISO/IEC 14492:2001(E) iv ISO/IEC 2001 All rights reserved Page6.4 Text Region Decoding Procedure 236.4.1 General description 236.4.2 Input param
15、eters. 236.4.3 Return value. 246.4.4 Variables used in decoding. 246.4.5 Decoding the text region. 256.4.6 Strip delta T . 286.4.7 First symbol instance S coordinate 286.4.8 Subsequent symbol instance S coordinate . 286.4.9 Symbol instance T coordinate. 296.4.10 Symbol instance symbol ID 296.4.11 Sy
16、mbol instance bitmap . 296.5 Symbol Dictionary Decoding Procedure 306.5.1 General description 306.5.2 Input parameters. 306.5.3 Return value. 306.5.4 Variables used in decoding. 306.5.5 Decoding the symbol dictionary . 326.5.6 Height class delta height. 346.5.7 Delta width 346.5.8 Symbol bitmap. 346
17、.5.9 Height class collective bitmap 376.5.10 Exported symbols. 376.6 Halftone Region Decoding Procedure 386.6.1 General description 386.6.2 Input parameters. 386.6.3 Return value. 396.6.4 Variables used in decoding. 396.6.5 Decoding the halftone region 396.7 Pattern Dictionary Decoding Procedure . 4
18、26.7.1 General description 426.7.2 Input parameters. 426.7.3 Return value. 426.7.4 Variables used in decoding. 436.7.5 Decoding the pattern dictionary 437 Control Decoding Procedure 447.1 General description . 447.2 Segment header syntax 457.2.1 Segment header fields 457.2.2 Segment number 457.2.3 S
19、egment header flags . 457.2.4 Referred-to segment count and retention flags. 457.2.5 Referred-to segment numbers. 477.2.6 Segment page association. 477.2.7 Segment data length . 477.2.8 Segment header example 477.3 Segment types. 487.3.1 Rules for segment references 497.3.2 Rules for page associatio
20、ns. 507.4 Segment syntaxes 507.4.1 Region segment information field. 507.4.2 Symbol dictionary segment syntax 517.4.3 Text region segment syntax 567.4.4 Pattern dictionary segment syntax. 667.4.5 Halftone region segment syntax 677.4.6 Generic region segment syntax. 707.4.7 Generic refinement region
21、syntax . 727.4.8 Page information segment syntax . 73ISO/IEC 14492:2001(E) ISO/IEC 2001 All rights reserved vPage7.4.9 End of page segment syntax . 767.4.10 End of stripe segment syntax 767.4.11 End of file segment syntax . 767.4.12 Profiles segment syntax 767.4.13 Code table segment syntax . 777.4.
22、14 Extension segment syntax. 777.4.15 Defined extension types . 778 Page Make-up 788.1 Decoder model 788.2 Page image composition 78Annex A Arithmetic Integer Decoding Procedure 82A.1 General description . 82A.2 Procedure for decoding values (except IAID). 82A.3 The IAID decoding procedure .84Annex
23、B Huffman Table Decoding Procedure . 86B.1 General description . 86B.2 Code table structure. 86B.2.1 Code table flags . 87B.2.2 Code table lowest value 87B.2.3 Code table highest value. 87B.3 Assigning the prefix codes. 87B.4 Using a Huffman table 88B.5 Standard Huffman tables . 89Annex C Gray-scale
24、 Image Decoding Procedure. 97C.1 General description . 97C.2 Input parameters 97C.3 Return value 97C.4 Variables used in decoding 97C.5 Decoding the gray-scale image 98Annex D File Formats. 99D.1 Sequential organisation . 99D.2 Random-access organisation 99D.3 Embedded organisation . 100D.4 File hea
25、der syntax . 100D.4.1 ID string. 100D.4.2 File header flags. 100D.4.3 Number of pages 100Annex E Arithmetic Coding 101E.1 Binary encoding 101E.1.1 Recursive interval subdivision 101E.1.2 Coding conventions and approximations. 101E.2 Description of the arithmetic encoder. 102E.2.1 Encoder code regist
26、er conventions 103E.2.2 Encoding a decision (ENCODE). 103E.2.3 Encoding a 1 or 0 (CODE1 and CODE0) 103E.2.4 Encoding an MPS or LPS (CODEMPS and CODELPS) . 104E.2.5 Probability estimation. 105E.2.6 Renormalisation in the encoder (RENORME). 105E.2.7 Compressed data output (BYTEOUT) 106E.2.8 Initialisa
27、tion of the encoder (INITENC) 107E.2.9 Termination of encoding (FLUSH) . 107E.2.10 Minimisation of the compressed data. 107ISO/IEC 14492:2001(E) vi ISO/IEC 2001 All rights reserved PageE.3 Arithmetic decoding procedure 109E.3.1 Decoder code register conventions 111E.3.2 Decoding a decision (DECODE)
28、111E.3.3 Renormalisation in the decoder (RENORMD) 111E.3.4 Compressed data input (BYTEIN) 111E.3.5 Initialisation of the decoder (INITDEC) 114E.3.6 Resynchronisation of the decoder . 114E.3.7 Resetting arithmetic coding statistics 115E.3.8 Saving arithmetic coding statistics 115Annex F Profiles 116A
29、nnex G Arithmetic Decoding Procedure (Software Conventions) 119Annex H Datastream Example and Test Sequence 121H.1 Datastream example 121H.2 Test sequence for arithmetic coder. 142Bibliography. 149Annex I P atents . 147ISO/IEC 14492:2001(E) ISO/IEC 2001 All rights reserved viiForeword ISO (the Inter
30、national Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees establis
31、hed by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the fi
32、eld of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of the joint technical committee is to prepare International Standards. Draf
33、t International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 14492 was prepared by Joint Technical Com
34、mittee ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information, in collaboration with ITU-T. The identical text is published as ITU-T Recommandation T.88. Annexes A, B, C, D, E and F form a normative part of ISO/IEC 14492. Annexes G,
35、 H and I are for information only. 0 IntroductionThis Recommendation | International Standard, informally called JBIG2, defines a coding method for bi-level images(e.g. black and white printed matter). These are images consisting of a single rectangular bit plane, with each pixel takingon one of jus
36、t two possible colours. Multiple colours are to be handled using an appropriate higher level standard such asITU-T Recommendation T.44. It is being drafted by the Joint Bi-level Image Experts Group (JBIG), a “CollaborativeTeam“, established in 1988, that reports both to ISO/IEC JTC 1/SC29/WG1 and to
37、 ITU-T.Compression of this type of image is also addressed by existing facsimile standards, for example by the compressionalgorithms in ITU-T Recommendations T.4 (MH, MR), T.6 (MMR), T.82 (JBIG1), and T.85 (Application profile ofJBIG1 for facsimile). Besides the obvious facsimile application, JBIG2
38、will be useful for document storage andarchiving, coding images on the World Wide Web, wireless data transmission, print spooling, and even teleconferencing.As the result of a process that ended in 1993, JBIG produced a first coding standard formally designated ITU-TRecommendation T.82 | Internation
39、al Standard ISO/IEC 11544, which is informally known as JBIG or JBIG1. JBIG1 isintended to behave as lossless and progressive (lossy-to-lossless) coding. Though it has the capability of lossy coding,the lossy images produced by JBIG1 have significantly lower quality than the original images because
40、the number ofpixels in the lossy image cannot exceed one quarter of those in the original image.On the contrary, JBIG2 was explicitly prepared for lossy, lossless, and lossy-to-lossless image compression. The designgoal for JBIG2 was to allow for lossless compression performance better than that of
41、the existing standards, and to allowfor lossy compression at much higher compression ratios than the lossless ratios of the existing standards, with almost novisible degradation of quality. In addition, JBIG2 allows both quality-progressive coding, with the progression goingfrom lower to higher (or
42、lossless) quality, and content-progressive coding, successively adding different types of imagedata (for example, first text, then halftones). A typical JBIG2 encoder decomposes the input bi-level image into severalregions and codes each of the regions separately using a different coding method. Suc
43、h content-based decomposition isvery desirable especially in interactive multimedia applications. JBIG2 can also handle a set of images (multiple pagedocument) in an explicit manner.As is typical with image compression standards, JBIG2 explicitly defines the requirements of a compliant bitstream, an
44、dthus defines decoder behaviour. JBIG2 does not explicitly define a standard encoder, but instead is flexible enough toallow sophisticated encoder design. In fact, encoder design will be a major differentiator among competing JBIG2implementations.Although this Recommendation | International Standard
45、 is phrased in terms of actions to be taken by decoders tointerpret a bitstream, any decoder that produces the correct result (as defined by those actions) is compliant, regardless ofthe actions it actually takes.Annexes A, B, C, D, E, and F are normative, and thus form an integral part of this This
46、 Recommendation | InternationalStandard. Annexes G and H are informative, and thus do not form an integral part of this Recommendation | InternationalStandard.0.1 Interpretation and use of the requirementsThis section is informative and designed to aid in interpreting the requirements of this Recomm
47、endation | InternationalStandard. The requirements are written to be as general as possible to allow a large amount of implementation flexibility.Hence the language of the requirements is not specific about applications or implementations. In this section acorrespondence is drawn between the general
48、 wording of the requirements and the intended use of this Recom-mendation | International Standard in typical applications.0.1.1 Subject matter for JBIG2 codingJBIG2 is used to code bi-level documents. A bi-level document contains one or more pages. A typical page containssome text data, that is, so
49、me characters of a small size arranged in horizontal or vertical rows. The characters in the textpart of a page are called symbols in JBIG2. A page may also contain “halftone data“, that is, gray-scale or colour multi-level images (e.g. photographs) that have been dithered to produce bi-level images. The periodic bitmap cells in thehalftone part of the page are called patterns in JBIG2. In addition, a page may contain other data, such as line art andnoise. Such non-text, non-halftone data is called generic data in JBIG2.The JBIG2 ima
