ISO/IEC 19794-2:2011

INTERNATIONAL ISO/IEC
STANDARD 19794-2
Second edition
2011-12-15
Information technology — Biometric data
interchange formats —
Part 2:
Finger minutiae data
Technologies de l'information — Formats d'échange de données
biométriques —
Partie 2: Données du point caractéristique du doigt

Reference number
©
ISO/IEC 2011
©  ISO/IEC 2011
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Published in Switzerland
ii © ISO/IEC 2011 – All rights reserved

Contents Page
Foreword .vi
Introduction.vii
1 Scope.1
2 Conformance .1
3 Normative references.2
4 Terms and definitions .2
5 Abbreviated terms .3
6 Minutiae extraction.3
6.1 Purpose .3
6.2 Minutia description.3
6.3 Minutia type.3
6.4 Minutia location .4
6.5 Minutiae direction.6
6.6 Core and delta placement.7
6.7 Encoding of multibyte quantities.7
7 Finger minutiae format types .8
7.1 Overview.8
7.2 Record format .8
7.3 On-card comparison format .8
8 Finger minutiae record format .9
8.1 Introduction.9
8.2 Record organization.9
8.3 General header .10
8.4 Finger minutiae representation format .11
8.5 Extended data .21
9 Finger minutiae on-card comparison format.29
9.1 Purpose .29
9.2 On-card comparison format .30
9.3 Number of minutiae and truncation.30
9.4 Minutiae order.32
9.5 Usage of extended data for the on-card comparison format.34
10 Registered format type identifiers .36
Annex A (normative) Conformance test methodology .37
Annex B (normative) Record format diagrams.38
Annex C (informative) Example data record .41
Annex D (informative) Handling of finger minutiae card formats .45
Annex E (normative) Capture device certifications.47
Annex F (normative) Detailed description of finger minutiae location, direction, and type .71
Bibliography.93

© ISO/IEC 2011 – All rights reserved iii

Figures
Figure 1 — Coordinate system . 4
Figure 2 — Location and direction of a ridge ending (encoded as valley skeleton bifurcation point) . 5
Figure 3 — Location and direction of a ridge bifurcation (encoded as ridge skeleton bifurcation point). 5
Figure 4 — Location and direction of a ridge skeleton endpoint . 6
Figure 5 — Example core and delta placement . 8
Figure 6 — Image quality layout . 16
Figure 7 — Example ridge count data . 23
Figure 8 — Eight-minutiae neighbourhood. 24
Figure 9 — Four-minutiae neighbourhood. 25

Tables
Table 1 — Format type options . 9
Table 2 — General header . 10
Table 3 — Finger minutiae representation format. 12
Table 4 — Extended data areas. 15
Table 5 — Capture device technology ID. 16
Table 6 — Identifiers for certification schemes specified in the annexes. 18
Table 7 — Finger position codes . 19
Table 8 — Finger impression codes . 19
Table 9 — Qualified finger minutia pixel record format . 20
Table 10 — Finger minutia pixel record format . 21
Table 11 — Extended data area type codes . 22
Table 12 — Ridge count extraction method codes. 23
Table 13 — Example ridge count data (non-specific extraction method, RCE method = 00 ). 26
Hex
Table 14 — On-card biometric comparison format. 30
Table 15 — DO Biometric comparison algorithm parameters. 31
Table 16 — Data object for number of minutiae. 32
Table 17 — Data object for minutiae order. 32
iv © ISO/IEC 2011 – All rights reserved

Table 18 — Values for minutiae order indication .32
Table 19 — Biometric data template .35
Table 20 — Encoding of feature handling indicator .36
Table 21 — Format type identifiers .36
Table E.1 — Preferred capture sizes .48
Table E.2 — MTF Requirement using sine wave target .50
Table E.3 — CTF Requirement using bar target (nominal test frequencies) .50
Table E.4 — Basic requirements.55
Table E.5 — CTF and MTF Requirements at nominal test frequencies .57
Table E.6 — Minimum and maximum modulation.66
Table E.7 — Dimensions of the target structures.67

© ISO/IEC 2011 – 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 in 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 non-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 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 casting 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 19794-2 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 37, Biometrics.
This second edition cancels and replaces the first edition (ISO/IEC 19794-2:2005). It reflects the
harmonization across the second generation of ISO/IEC 19794. A new Clause 7 has been added to describe
the finger minutiae format types; Clause 8 contains descriptions of the harmonized general and representation
headers; and Clauses 8 and 9 have been technically revised. All annexes have been technically revised.
Annex A is under development and will contain an amendment for conformance testing methodology for this
part of ISO/IEC 19794. The former Annex B “Fingerprint Image Quality Specifications” has been removed.
Annex E contains three examples of capture device certifications. Annex F provides descriptions of fingerprint
minutiae location, direction, and type.
ISO/IEC
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