1、INTERNATIONAL STANDARD ISO/IEC 92814 First edition 1990-08-01 Information technology - Picture coding methods - Part 1: Identification Technologies de /information - M6thodes de codage dimage - Partie 1: identification Reference number ISOAEC 9281-1:1990(E) Processed and adopted by ASC NCITS and app
2、roved by ANSI as an American National Standard.Date of ANSI Approval: 1/14/99Published by American National Standards Institute,11 West 42nd Street, New York, New York 10036Copyright 1999 by Information Technology Industry Council (ITI).All rights reserved.These materials are subject to copyright cl
3、aims of International Standardization Organization (ISO),International Electrotechnical Commission (IEC), American National Standards Institute (ANSI), andInformation Technology Industry Council (ITI). Not for resale. No part of this publication may be reproducedin any form, including an electronic
4、retrieval system, without the prior written permission of ITI. All requestspertaining to this standard should be submitted to ITI, 1250 Eye Street NW, Washington, DC 20005.Printed in the United States of AmericaAdopted by INCITS (InterNational Committee for Information Technology Standards) as an Am
5、erican National Standard.Date of ANSI Approval: 1/14/99Published 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 copyright claims of International
6、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 an electronic retrieval system, wit
7、houtthe 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 AmericaISOllEC 9281-1:1990(E) Foreword IS0 (the International Organization for Standardization) and IEC (the Internati
8、onal Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields
9、 of technical activity. IS0 and IEC technical com- mittees collaborate in fields of mutual interest. Other international or- ganizations, governmental and non-governmental, in liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC have established a
10、 joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bod- ies for voting. Publication as an International Standard requires ap- proval by at least 75 % of the national bodies casting a vote. International Standar
11、d ISO/IEC 9281-l was prepared by Joint Technical Committee ISO/IEC JTC 1, information technology. ISO/IEC 9281 consists of the following parts, under the general title In- formation technology - Picture coding methods: - Part I: Identification - Part 2: Procedure for registration Annexes A and B of
12、this part of ISO/IEC 9281 are for information only. 0 ISOllEC 1990 All rights reserved. No part of thls publication may be reproduced or utilized in any form or by any means, electronic or mechanical, Including photocopying and microfilm, without permlsslon in writing from the publisher. ISO/IEC Cop
13、yright Office l Case Postale 56 l CH-1211 Genive 20 l Switzerland Printed in Switzerland ii ISOllEC 9281-1:1990(E) Introduction This part of ISOAEC 9281 specifies the identification methods for coding of pictorial information in digital form where the information can be stored, processed or intercha
14、nged by telecommunications or by the ex- change of physical storage media. Techniques are provided to switch between picture coding methods in the picture coding environment, as well as to switch between the picture coding environment and coding systems according to IS0 2022. Thus, this part of ISOA
15、EC 9281 is limited to coding and does not address functional aspects which are covered by other International Standards, e.g. IS0 8613. IS0 2022 deals with byte-oriented coding and extension techniques for graphic characters and control functions, and assigns specific areas of the code table to grap
16、hic characters and to control functions. In picture coding this structure cannot be retained. Picture coding methods con- stitute, therefore, coding systems different from that of IS0 2022. Indeed, the control functions may take the form of operations (opcodes) and operands. Because this part of ISO
17、AEC 9281 is intended to serve as a basis for a number of other standards for specific picture coding methods, an in- troduction to its basic concepts is included in annex B. . . . III INTERNATIONAL STANDARD ISOllEC 9281-1:1990(E) Information technology - Picture coding methods - Part 1: Identificati
18、on 1 Scope Members of IEC and IS0 maintain registers of cur- rently valid International Standards. This part of ISO/IEC 9281 specifies the identification methods for coding of pictorial information in digital form. It does not specify the contents of the data field of a picture entity. For instance,
19、 this field may also IS0 2022:1986, information processing - /SO 7-bit and 8-bit coded character sets - Code extension techniques. contain audio and/or animation data associated with the data specifying the picture(s). IS0 2375:1985, Data processing - Procedure for the registration of escape sequenc
20、es. This part of ISO/IEC 9281 serves as a basis for a number of standards. In combination with one or more of those, pictorial information in digital form, using one or more methods of coding, may be built up into a document for visual comprehension. Graphic characters coded in accordance with other
21、 standards can also be combined with the picture in- formation. The coded information from such a docu- ment may be processed, and transmitted by telecommunications systems. IS0 6429:1988, fnformation processing - Control functions for 7-bit and B-bit coded character sets. ISO/IEC 9281-2:1990, Infor
22、mation technology - Pic- ture coding methods - Part 2: Procedure for regis- tration. international Register of Coded Character Sets To Be Used with Escape Sequences. This part of ISO/IEC 9261 also specifies a technique for switching between character-coded information and digital pictorial informati
23、on, and between differ- ent picture coding methods. 4 Definitions For the purposes of this part of ISO/IEC 9281, the following definitions apply. 2 Conformance 4.1 picture: A bounded representation of visual in- formation. It may comprise, for example, a photo- graph, a diagram or a chart with capti
24、ons, or a combination of these. It may also comprise audio and/or animation data associated with the visual in- formation. A picture coding method is in conformance with this part of ISO/IEC 9281 if it satisfies the requirements of clause 5, clause 6 and clause 7. 3 Normative references The followin
25、g standards contain provisions which, through reference in this text, constitute provisions of this part of ISO/IEC 9281. At the time of publica- tion, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO/IEC 9281 are encourage
26、d to investigate the possibility of applying the most recent editions of the standards indicated below. 4.2 picture coding: The representation in digital form of a picture, particularly for storage, inter- change or processing. 4.3 graphic element: A constituent of an array from which a picture is c
27、onstructed. 4.4 picture coding method: A specific way of coding a distinctive type of graphic element constituting a picture. 1 ISOllEC 9281-1:1990(E) 4.5 picture coding environment: Applications using picture coding methods. 5.2 Coding 4.6 picture entity (PE): The complete coded repre- sentation of
28、 a picture or part of a picture. It com- prises a Picture Control Entity and a Picture Data Entity. In the following description - the Picture Identifier byte (PI). CMI = PM + PI The PM byte shall specify the mode (see 6.2) and shall be in the range 02/00 to 03/14. The PI byte shall specify a coding
29、 method and shall be in the range 04100 to 07/15. Bit combination 03115 shall be reserved for future extensions (E) of the code table. ISOllEC 9281-1:1990(E) 1h.b In In In In In Ifi In II II 11 II II 11 11 11 I 5 “0 -“o “0 I “0 I “1 I “1 I I I-1 I; I I I I m m . I 0 10 I.0 10 11 11 I.1 .I . 0 0 1 10
30、 0l1I1101011I1101011 1 h. f 1 n 1 I-L 1 Picture Picture Mode Identifier (PM) (PI) Figure 3 - Code table for the bytes of the CMI ISOllEC 9281-1:1990(E) 6.2 Specification of modes 7.2 Direct switching Several modes have already been defined or will be defined in the future. Each of these modes shall
31、be identified by a PM byte as follows: PM Mode 02100 Incremental mode 02JOl Geometric mode 02102 Photographic mode Further modes, when defined, will be identified by a PM byte. Each combination of two or more modes will also be identified by a PM byte. If the application is not under the control of
32、a high level protocol, or if the latter allows it, direct switching between IS0 2022 and picture coding methods identified by this part of ISOAEC 9281 shall be performed by ESC 02/05 F and ESC 02/05 04/00 (see figure 5). IS0 2022 ISOAEC 9281-1 ESC 02/05 F1 I Character Coding ESC 02/05 F2 7 Switching
33、 from character coding to picture coding and vice versa Depending on the application considered, switching from character coding in accordance with IS0 2022 to picture coding methods identified according to this International Standard and vice versa, is per- formed by different means. 7.1 High level
34、 protocol ESCOZ/OSF, a If the application is controlled by a high level proto- col, this switching is performed by this protocol with its own means. Exit from character coding or from picture coding to the high level protocol is per- formed by the control function CODING METHOD DELIMITER (CMD), the
35、coded representation of which is ESC 06/04. The invocation of a coded character set in accordance with IS0 2022 or of a picture coding method identified by this pat-l of ISOAEC 9281 is performed by the specific means of the high level protocol (see figure4). ESC02/0504/00 Figure 5 - Direct switching
36、 For each picture coding method identified by a CMI, a corresponding registration will be made in the International Register of Coded Character Sets to be Used with Escape Sequences, so that to each method identified by a CMI a specific escape se- quence of the type ESC 02105 F will correspond. High
37、 level protocol 4 4 Return from any picture coding method to character coding shall be always performed by , i, 202; EjCO6/04 / ls!,lEC 92J;CW04 ESC 0205. 04oo 7.3 Sequences of picture coding methods Unless the rules of the high level protocol or of the particular application requires it, switching
38、from one picture coding method to another shall be as speci- Figure 4 - High level protocol fled below. This applies both to 7.1 and 7.2. 5 ISOllEC 9281-1:1990(E) A PE can be followed by a second PE with the same or a different CMI: - If the CMI is the same, the second PE specifies the same picture
39、coding method as the first PE. - If the CMI is different, the second PE specifies a picture coding method different from that of the first PE. This second PE can, in turn, be followed by a further PE, and so on. 8 Registration Authority) For each picture coding method specified in an International S
40、tandard, or in a publicly available document, the CMI identifying this method shall be uniquely allocated by the Registration Authority for Picture Coding. The Registration Authority shall maintain a register of CMls allocated in accordance with the registration procedures given in ISO/IEC 9281-2. T
41、he Registration Authority is entrusted with the fol- lowing functions: a) b) cl d) to check the completeness of said publicly avail- able document; to allocate, modify and delete CMls in accord- ance with the rules provided; to maintain and publish the register when re- quired; to apply to the Regis
42、tration Authority for IS0 2375 for a registration of an escape sequence for each picture coding method registered in accordance with this part of ISO/IEC 9281. 1) For the purposes of this part of ISO/IEC 9281 and in accordance with the rules for the designation and operation of registration authorit
43、ies in the ISOllEC JTC 1 procedures, the IS0 and IEC Councils have designated the Association Francaise de Normalisation (AFNOR) to act as registration authority. 6 ISOllEC 9281-1:1990(E) Annex A (informative) Examples of application Table A.1 illustrates a correspondence between the different categ
44、ories of graphic elements (as de- scribed in annex B) and certain services or appli- cations where some or all of the graphic element categories are used. A consistent coding scheme is intended to be used for each graphic element category corresponding to one column of table A.1 in such a way as to
45、meet the requirements of preferably all the relevant services indicated in tableA.l. Whereas different levels of resolution or picture definition for the same category of graphic elements may be required within a ser- vice or for different services or applications, the coding scheme should ensure up
46、wards or down- wards compatibility across the different implemen- tation levels. Table A.1 - Graphic elements of different services (applications) Elements - Services (applications) Graphic character Character-coded Geometric Short line Photographic strings pictorial elements elements segments Pixel
47、 arrays images Videotex X X X X X X Teletex X X Computer graphics X X X - image processing X X X - - Tele-writing X X Slow-scan video X Teletex mixed mode X X X Phototelegraphy X ISOllEC 9281-1:1990(E) Annex B (informative) Introduction to the basic concepts A picture may be considered to be compose
48、d of graphic elements. Each graphic element may have attributes related to shape, size, gray scale/colour and position. A graphics function is an instruction or command used to create a graphic element. Each type of graphic element has certain distinguishing visual characteristics which make particu
49、lar picture coding methods relevant. It is not possible to sep- arate completely graphic element types as the same picture can be created by using several different types. Different graphic elements for which picture coding methods are applicable are as follows. 6.1 Picture element characters These are pre-determined shapes or patterns that are taken from a graphics repertoire and presented in adjacent character cells in order to construct a simple picture. Examples are mosaic and line drawings sets of characters. 8.2 Geometric elements These are characterized by their stylized app
