1、 Reference number ISO/IEC 24778:2008(E) ISO/IEC 2008INTERNATIONAL STANDARD ISO/IEC 24778 First edition 2008-02-15 Information technology Automatic identification and data capture techniques Aztec Code bar code symbology specification Technologies de linformation Techniques didentification automatiqu
2、e et de capture des donnes Spcification pour la symbologie de code barres du code Aztec ISO/IEC 24778:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which
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7、o.org Published in Switzerland ii ISO/IEC 2008 All rights reservedISO/IEC 24778:2008(E) ISO/IEC 2008 All rights reserved iii Contents Page Foreword. v Introduction . vi 1 Scope . 1 2 Normative references . 1 3 Terms, definitions, symbols and functions .1 3.1 Terms and definitions. 1 3.2 Symbols and
8、functions 2 4 Symbology characteristics 3 4.1 Basic characteristics 3 4.2 Summary of additional features 4 5 Symbol description. 4 5.1 Symbol structure 5 5.2 Symbol character structure and sequence 6 5.3 Symbol size and capacity 7 6 General encodation procedures 8 7 Symbol structure 9 7.1 Fixed patt
9、ern structures. 9 7.2 Mode Message encoding and structure . 10 7.3 Data message encoding and structure.11 8 Structured Append . 14 9 Reader initialization symbols 14 10 Extended Channel Interpretation 15 10.1 Encoding ECIs in Aztec Code 15 10.2 Code sets and ECIs 15 10.3 ECIs and Structured Append.
10、15 10.4 Post-decode protocol. 15 11 User considerations . 16 11.1 User selection of encoded message. 16 11.2 User selection of minimum error correction level 16 11.3 User selection of Structured Append . 16 11.4 User selection of optional symbol formats 16 12 Dimensions 16 13 User guidelines . 17 13
11、.1 Human readable interpretation 17 13.2 Autodiscrimination capability . 17 13.3 User-defined application parameters . 17 14 Reference decode algorithm . 17 14.1 Finding candidate symbols . 18 14.2 Processing the bullseye image . 18 14.3 Decoding the Core Symbol 18 14.4 Decoding the data message 19
12、14.5 Translating the datawords . 20 15 Symbol quality 20 15.1 Symbol quality parameters 20 ISO/IEC 24778:2008(E) iv ISO/IEC 2008 All rights reserved15.2 Symbol print quality grading . 21 15.3 Process control measurements. 22 16 Transmitted data . 22 16.1 Basic interpretation 22 16.2 Protocol for FNC
13、1 . 22 16.3 Protocol for ECIs. 22 16.4 Symbology identifier. 23 16.5 Transmitted data example 23 Annex A (normative) Aztec Runes 24 Annex B (normative) Error detection and correction . 26 Annex C (normative) Topological bullseye search algorithm . 29 Annex D (normative) Linear crystal growing algori
14、thm . 33 Annex E (normative) Fixed Pattern Damage grading . 34 Annex F (normative) Symbology identifiers 36 Annex G (informative) Aztec Code symbol encoding example . 37 Annex H (informative) Achieving minimum symbol size 41 Annex I (informative) Useful process control techniques 43 Bibliography . 4
15、5 ISO/IEC 24778:2008(E) ISO/IEC 2008 All rights reserved v Foreword ISO (the International 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 i
16、n the development of International Standards through technical committees established 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 no
17、n-governmental, in liaison with ISO and IEC, also take part in the work. In the field 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 2. The main
18、 task of the joint technical committee is to prepare International Standards. Draft 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 castin
19、g a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 24778 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information
20、technology, Subcommittee SC 31, Automatic identification and data capture techniques. ISO/IEC 24778:2008(E) vi ISO/IEC 2008 All rights reservedIntroduction Aztec Code is a two-dimensional matrix symbology whose symbols are nominally square, made up of square modules on a square grid, with a square b
21、ullseye pattern at their center. Aztec Code symbols can encode from small to large amounts of data with user-selected percentages of error correction. Manufacturers of bar code equipment and users of the technology require publicly available standard symbology specifications to which they can refer
22、when developing equipment and application standards. The publication of standardised symbology specifications is designed to achieve this. INTERNATIONAL STANDARD ISO/IEC 24778:2008(E) ISO/IEC 2008 All rights reserved 1 Information technology Automatic identification and data capture techniques Aztec
23、 Code bar code symbology specification 1 Scope This International Standard defines the requirements for the symbology known as Aztec Code. It specifies the Aztec Code symbology characteristics including data character encodation, rules for error control encoding, the graphical symbol structure, symb
24、ol dimensions and print quality requirements, a reference decoding algorithm, and user-selectable application parameters. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undate
25、d references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 646:1991, Information technology ISO 7-bit coded character set for information interchange ISO/IEC 15415:2004, Information technology Automatic identification and data capture techniques Bar code
26、print quality test specification Two-dimensional symbols ISO/IEC 15424, Information technology Automatic identification and data capture techniques Data Carrier Identifiers (including Symbology Identifiers) ISO/IEC 19762 (all parts), Information technology Automatic identification and data capture (
27、AIDC) techniques Harmonized vocabulary AIM Inc. International Technical Specification: Extended Channel Interpretations Part 1, Identification Schemes and Protocols Part 2, Registration Procedure for Coded Character Sets and Other Data Formats Character Set Register 3 Terms, definitions, symbols and
28、 functions 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in ISO/IEC 19762 and the following apply. 3.1.1 bullseye set of concentric square rings used as the finder pattern in Aztec Code ISO/IEC 24778:2008(E) 2 ISO/IEC 2008 All rights reserved3.1.2 check
29、word codeword which is included in a symbol for error correction and/or error detection 3.1.3 dataword codeword which is part of the data message encoded in a symbol 3.1.4 domino 2-module sub-structure of the symbol character in Aztec Code which is the elemental entity used in graphical encoding of
30、the symbol 3.1.5 Mode Message short fixed-length, error-corrected subsidiary message within an Aztec Code symbol which directly encodes the symbols size and data message length 3.2 Symbols and functions 3.2.1 Mathematical symbols For the purposes of this document, the following mathematical symbols
31、apply. B the number of bits in each codeword C bthe symbol capacity in number of bits C wthe symbol capacity in number of codewords D the number of data (message) codewords in the symbol K the number of error correction codewords in the symbol, equal to C w- D L the number of data layers (1 to 32) i
32、n the symbol, defining its size m the symbology identifier modifier value X the X-dimension or nominal square grid spacing x a general variable used to express error correction polynomials (x,y) Cartesian coordinates within the module grid 3.2.2 Mathematical functions and operations For the purposes
33、 of this document, the following mathematical functions and operations apply. abs() is the absolute value function div is the integer division operator max(a,b) is the greater of a and b mod is the remainder after integer division ISO/IEC 24778:2008(E) ISO/IEC 2008 All rights reserved 3 4 Symbology
34、characteristics 4.1 Basic characteristics Aztec Code is a two dimensional matrix symbology with the following basic characteristics: a. Encodable character set: 1. All 8-bit values can be encoded. The default interpretation shall be: a. for values 0 to 127, in accordance with the U.S. national versi
35、on of ISO/IEC 646; (NOTE: This version consists of the GO set of ISO/IEC 646 and the CO set of ISO/IEC 6429 with values 28 to 31 modified to FS, GS, RS and US respectively.) b. for values 128 - 255, in accordance with ISO/IEC 8859-1. This interpretation corresponds to ECI 000003. 2. Two non-data cha
36、racters can be encoded, FNC1 for compatibility with some existing applications and ECI escape sequences for the standardized encoding of message interpretation information. b. Representation of data: A dark module is a binary one and a light module is a binary zero. c. Symbol size: 1. The smallest A
37、ztec Code symbol is 15 x 15 modules square, and the largest is 151 x 151. 2. No quiet zone is required outside the bounds of the symbol. d. Data capacity (at recommended error correction level): 1. The smallest Aztec Code symbol encodes up to 13 numeric or 12 alphabetic characters or 6 bytes of data
38、. 2. The largest symbol encodes up to 3832 numeric or 3067 alphabetic characters or 1914 bytes of data. e. Selectable error correction: 1. User-selectable, from 5 % to 95 % of the data region, with a minimum of 3 codewords. 2. Recommended level is 23 % of symbol capacity plus 3 codewords. f. Code ty
39、pe: Matrix g. Orientation independent: Yes ISO/IEC 24778:2008(E) 4 ISO/IEC 2008 All rights reserved4.2 Summary of additional features The following summarizes additional features that are inherent or optional in Aztec Code: a. Reflectance Reversal (Inherent): Though Aztec Code symbols are shown and
40、described in this specification always with the finders center dark and with dark modules encoding binary 1s throughout, symbols exhibiting the opposite reflectance characteristics are easily autodiscriminated and decoded with the standard reader. b. Mirror Image (Inherent): Images which contain an
41、Aztec Code symbol in mirror reversal, either because they are obtained using a reflected optical path, a reversed scan direction, or from behind through a clear substrate, are easily autodiscriminated and decoded with the standard reader. c. Extended Channel Interpretation (Optional): The ECI mechan
42、ism enables characters from various character sets (e.g. Arabic, Cyrillic, Greek, Hebrew) and other data interpretations or industry-specific requirements to be represented. d. Structured Append (Optional): Structured Append allows files of data to be represented logically and continually in up to 2
43、6 Aztec Code symbols. The symbols may be scanned in any sequence to enable the original data to be correctly reconstructed. e. Reader Initialization Symbols (Optional): A distinct format of Aztec Code symbol is available for use in barcode menus for reader initialization. The encoded message in thes
44、e special symbols is never passed on to an application. f. Aztec “Runes” (Optional): a series of 256 small, machine-readable marks compatible with Aztec Code are available for special applications. See Annex A. 5 Symbol description Aztec Code symbols are nominally square, made up of square modules o
45、n a square grid, with a square bullseye pattern at their center. Figure 1 shows two representative Aztec Code symbols, a small 1-layer symbol on the left which encodes 12 digits with 47 % error correction and a larger 6-layer symbol on the right which encodes 168 text characters with 30 % error corr
46、ection. Figure 1 Representative Aztec Code symbols These symbols illustrate the two basic formats of Aztec Code symbols: on the left is a “compact” Aztec Code symbol, visually characterized by a 2-ring bullseye, useful for encoding shorter messages efficiently, while on the right is a “full-range” A
47、ztec Code symbol, visually characterized by a 3-ring bullseye, which supports much larger symbols for longer data messages. Since encoders can autoselect and decoders autodiscriminate between the two formats, a seamless transition is achieved to cover the full spectrum of applications. ISO/IEC 24778
48、:2008(E) ISO/IEC 2008 All rights reserved 5 5.1 Symbol structure The underlying structure of a compact Aztec Code symbol is shown in Figure 2, and that of a full-range Aztec Code symbol is shown in Figure 3. In both cases, the Aztec Code symbol has at its center a Core Symbol which is then surrounde
49、d by data fields on all four sides. Layer 1 - - - - Layer 2 - - - - Layer 3 - - - - Layer 4 - - - - MODE BITS - - - Fixed Structures Orientation Patterns Finder Pattern Variable Structures Data Layers Mode MessageFigure 2 Structure of a “compact” Aztec Code symbol Layer 1 - - - - Layer 2 - - - - Layer 3 - - - - Layer 4 - - - - Layer 5 - - - - La yer 6 - - - - MODE BITS - - - - Fixed Structures Orientation Patterns Reference Grid Variable Structures Mode Message Data Layers Finder PatternFigure 3 St
