ISO/IEC 39794-9:2021
(Main)Information technology — Extensible biometric data interchange formats — Part 9: Vascular image data
Information technology — Extensible biometric data interchange formats — Part 9: Vascular image data
This document specifies — generic extensible data interchange formats for the representation of vascular image data: a tagged binary data format based on an extensible specification in ASN.1 and a textual data format based on an XML schema definition that are both capable of holding the same information, — examples of data record contents, — application specific requirements, recommendations, and best practices in data acquisition, and — conformance test assertions and conformance test procedures applicable to this document.
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INTERNATIONAL ISO/IEC
STANDARD 39794-9
First edition
2021-06
Information technology — Extensible
biometric data interchange formats —
Part 9:
Vascular image data
Reference number
ISO/IEC 39794-9:2021(E)
©
ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC 39794-9:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 39794-9:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Conformance . 2
6 Modality-specific information . 3
6.1 Capture recommendations . 3
6.1.1 Image area . 3
6.1.2 Illumination . 3
6.1.3 Normalization of projection . 3
6.1.4 Occlusion by opaque artifacts . 3
6.2 Image coordinate system considerations . 3
6.2.1 Standard pose . 3
6.2.2 Object coordinate system . 5
6.3 Image representation requirements . 6
6.3.1 General. 6
6.3.2 Pixel aspect ratio . 6
6.3.3 Bit-depth . 6
6.3.4 Spatial sampling rate . 6
7 Abstract data elements . 7
7.1 Purpose and overall structure . 7
7.2 Vascular image data block . 8
7.3 Version block . 8
7.4 Representation blocks . 8
7.5 Position . 8
7.6 Image data format . 8
7.6.1 Supported image data formats . 8
7.6.2 PGM format definition . . 8
7.7 Vascular image data . 9
7.8 Capture date/time block . . 9
7.9 Capture device block . 9
7.9.1 Model identifier block . 9
7.9.2 Capture device technology identifier . 9
7.9.3 Certification identifier block. 9
7.10 Quality blocks . 9
7.11 Scan resolution block .10
7.12 Pixel aspect ratio block .10
7.13 Bit-depth .10
7.14 Rotation angle .10
7.15 Image flip .10
7.16 Illumination .10
7.17 Imaging method .11
7.18 Image background .11
7.19 PAD data block.11
7.20 Segmentation blocks .11
7.21 Annotation blocks .11
7.22 Comment blocks .11
7.23 Vendor specific data blocks .12
8 Encoding .12
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ISO/IEC 39794-9:2021(E)
8.1 Tagged binary encoding .12
8.2 XML encoding .12
9 Registered format type identifiers .12
Annex A (normative) Formal specifications .13
Annex B (informative) Encording examples .25
Annex C (normative) Conformance test methodology .27
Bibliography .31
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ISO/IEC 39794-9:2021(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for
the different types of document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives or www .iec .ch/ members
_experts/ refdocs).
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. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC
list of patent declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html. In the IEC, see www .iec .ch/ understanding -standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 37, Biometrics.
A list of all parts in the ISO/IEC 39794 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html and www .iec .ch/ national
-committees.
© ISO/IEC 2021 – All rights reserved v
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ISO/IEC 39794-9:2021(E)
Introduction
Biometric data interchange formats enable the interoperability of different biometric systems. The
first generation of biometric data interchange formats was published between 2005 and 2007 in the
first edition of the ISO/IEC 19794 series. From 2011 onwards, the second generation of biometric data
interchange formats was published in the form of second editions of the established parts and first
editions of a number of new parts of the ISO/IEC 19794 series. In the second generation of biometric
data interchange formats, new useful data elements such as data elements related to biometric sample
quality have been added, the header data structures have been harmonized across all parts of the
ISO/IEC 19794 series, and XML encoding has been added in addition to the binary encoding.
In anticipation of the future need for additional data elements and to avoid future compatibility issues,
ISO/IEC JTC 1/SC 37 has developed the ISO/IEC 39794 series as a third generation of biometric data
interchange formats, defining extensible biometric data interchange formats capable of including
future extensions in a defined manner. Extensible specifications in ASN.1 (Abstract Syntax Notation
One) and the distinguished encoding rules of ASN.1 form the basis for encoding biometric data in binary
tag-length-value formats. XML Schema Definitions form the basis for encoding biometric data in XML
(eXtensible Markup Language).
This third generation of vascular image data interchange formats complements ISO/IEC 19794-9:2007
and ISO/IEC 19794-9:2011.
This document is intended for those applications requiring the exchange of raw or processed vascular
images (for example, palm images) that are sometimes not necessarily limited in the amount of
resources available for data storage or transmitting time. It can be used for the exchange of scanned
vascular images containing detailed image pixel information.
Use of the captured or processed image allows interoperability among biometric systems relying on
pattern-based or other algorithms. Thus, data from the captured hand image offers the developer more
freedom in choosing or combining comparison algorithms. For example, an enrolment image can be
stored on a contactless chip located on an identification document. This allows future verification of the
holder of the document with systems that rely on pattern-based algorithms. Establishment of an image-
based representation of vascular information will not rely on pre-established definitions of patterns
or other types. It will provide implementers with the flexibility to accommodate images captured from
dissimilar devices, varying image sizes, spatial sampling rates, and different grey-scale depths. Use of
the vascular image will allow each vendor to implement their own algorithms to determine whether
two vascular records are from the same hand.
This document supports both binary and XML encoding, to support a spectrum of user requirements.
With XML, this document meets the requirements of modern IT architectures. With binary encoding,
this document is also able to be used in bandwidth or storage-constrained environments.
vi © ISO/IEC 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO/IEC 39794-9:2021(E)
Information technology — Extensible biometric data
interchange formats —
Part 9:
Vascular image data
1 Scope
This document specifies
— generic extensible data interchange formats for the representation of vascular image data: a tagged
binary data format based on an extensible specification in ASN.1 and a textual data format based on
an XML schema definition that are both capable of holding the same information,
— examples of data record contents,
— application specific requirements, recommendations, and best practices in data acquisition, and
— conformance test assertions and conformance test procedures applicable to this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 39794-1, Information technology — Extensible biometric data interchange formats — Part 1:
Framework
ISO/IEC 14495-1, Information technology — Lossless and near-lossless compression of continuous-tone still
images: Baseline — Part 1:
ISO/IEC 15444-1, Information technology — JPEG 2000 image coding system — Part 1: Core coding system
ISO/IEC 15948, Information technology — Computer graphics and image processing — Portable Network
Graphics (PNG): Functional specification
ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1) – Part 1: Specification of
basic notation
ISO/IEC 8825-1, Information technology – ASN.1 encoding rules – Part 1: Specification of Basic Encoding
Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 39794-1 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
© ISO/IEC 2021 – All rights reserved 1
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ISO/IEC 39794-9:2021(E)
3.1
centroid
centre of gravity
Note 1 to entry: In this document, this term is used to define a unique location within a silhouette image that can
be assumed as the origin of a coordinate system.
3.2
dorsal
back side of a finger or a hand
3.3
ventral
palm side of a finger or a hand
3.4
vascular biometric image
captured raw or processed image that represents physical characteristics or traits of vascular pattern
used to recognize the identity or verify the claimed identity of an individual
4 Symbols and abbreviated terms
ICS implementation conformance statement
JPEG joint photographic experts group
MIR midrange infrared
NIR near infrared
nm nanometre
PGM portable gray map
PNG portable network graphics
ppcm pixels per centimetre
RGB red, green, blue color model
VIR vascular biometric image record
5 Conformance
A biometric data block (BDB) conforms to this document if it satisfies all of the requirements related to:
— its data structure, data values and the relationships between its data elements as specified
throughout Clauses 6, 7, 8 and Annex A, and
— the relationship between its data values and the input biometric data from which the biometric data
record was generated as specified throughout Clauses 6, 7, 8 and Annex A.
A system that produces biometric data records conforms to this document if all biometric data
records that it outputs conform to this document (as defined above) as claimed in the implementation
conformance statement (ICS) associated with that system. A system does not need to be capable of
producing biometric data records that cover all possible aspects of this document, but only those that
are claimed to be supported by the system in the ICS.
A system that uses biometric data records is conformant to this document if it can read, and use for the
purpose intended by that system, all biometric data records that conform to this document (as defined
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ISO/IEC 39794-9:2021(E)
in the list above) as claimed in the ICS associated with that system. A system does not need to be capable
of using biometric data records that cover all possible aspects of this document, but only those that are
claimed to be supported by the system in an ICS.
Conformance test methodology shall be in accordance with Annex C.
6 Modality-specific information
6.1 Capture recommendations
6.1.1 Image area
Vascular pattern biometric technologies obtain images from different locations of the human body.
The technologies currently available employ images from the finger, back of the hand, and palm side of
the hand. The location used for imaging shall be specified in the format. Also, the direction (left/right)
of hand and/or finger index (thumb, index, middle, ring, and little) shall be specified. This document
reserves fields for future development of technologies potentially using different parts of the human
body.
6.1.2 Illumination
For the capture of vascular biometric images, the skin is typically illuminated using NIR wavelengths in
the range of approximately 700 to 1 200 nm. The angle from the light source to the tangent plane of the
skin’s surface is not defined in VIR because technologies that use a reflectance image may use diffuse
illumination instead of direct illumination for the purpose of avoiding specular reflectance. Instead,
this document specifies that the image is either based on transparency or reflectance of the observed
biometric characteristic. Two or more wavelengths of the illumination light source may be specified in
the case that multiple different light sources are used for background masking.
6.1.3 Normalization of projection
The captured image shall be an orthographic projection of the body area being imaged. If the original
raw image is not orthographic to the body area, it shall be converted to an orthographically projected
one. Any major geometric distortion caused by the optical system shall also be eliminated prior to
creation of the VIR.
6.1.4 Occlusion by opaque artifacts
Some opaque artifacts, such as rings, tattoos, bandages, etc., can occlude vascular patterns. Using
images including occlusions should be avoided.
6.2 Image coordinate system considerations
6.2.1 Standard pose
6.2.1.1 General
This document defines the standard poses for capturing raw images of target body areas. Based
on these standard poses, object (target area of the human body) coordinate systems are defined as
described in subclause 6.2.2.
6.2.1.2 Palm
The palm area shall not be bent and each finger boundary shall be exposed to the camera. Fingers shall
be straight. An example of the standard pose of a palm is shown in Figure 1. In the standard pose, the
camera’s direction is parallel to the z-axis of the palm coordinate system defined in subclause 6.2.2.2.
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ISO/IEC 39794-9:2021(E)
6.2.1.3 Finger
The standard pose is a straight finger. For clarity, the “frontal side” is defined as the ventral side of each
finger. An example of the standard pose of a finger is shown in Figure 2.
6.2.1.4 Back of the hand
The standard pose for the back of the hand shall be to position the hand with the dorsal side toward
the capture device with the tangent plane of the back of the hand in parallel with the image coordinate
space to produce an orthographic image of the back of the hand. An example of the standard pose of
the back of the hand is shown in Figure 3. In the standard pose, the camera’s direction is parallel to the
z-axis of the back of the hand coordinate system defined in subclause 6.2.2.3.
6.2.1.5 Standard poses for future modalities
This document shall reserve standard pose definitions of future technologies that can potentially
utilize different parts of the human body.
Key
x-axis perpendicular to the y-direction on the palm plane
y-axis along the opposite direction of the middle finger
z-axis perpendicular to the x-axis and away from the imaging device
NOTE The Euclidiean direction is right-handed.
Figure 1 — Standard pose and object coordinate system of palm vascular biometrics
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ISO/IEC 39794-9:2021(E)
Key
x-axis direction from root to tip
y-axis perpendicular both to the x and the z-axes
z-axis perpendicular to the x-axis and away from the frontal side
a
Frontal side.
NOTE The Euclidiean direction is right-handed.
Figure 2 — Standard pose and object coordinate system of finger vascular biometrics
Key
x-axis perpendicular to the y-direction along the tangent plane on the back of the hand
y-axis along the opposite direction of the middle finger
z-axis orthogonal to both the x-axis and the y-axis and away from the imaging device
NOTE The Euclidiean direction is right-handed.
Figure 3 — Standard pose and object coordinate system of the back of the hand vascular
biometrics
6.2.2 Object coordinate system
6.2.2.1 General
The vascular image header record provides an optional field that specifies the degree of rotation of
the vascular image out of the standard pose. To effectively specify the rotation angle, the object (target
body) coordinate system for each vascular technology is defined in this subclause. All of the coordinate
systems are right-handed Euclidian coordinate systems.
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ISO/IEC 39794-9:2021(E)
6.2.2.2 Palm
The y-axis of a palm object is along the opposite direction of the middle finger, while the x-axis is
perpendicular to the y-direction on the palm plane as shown in Figure 1. The z-axis shall be determined
by the right-handed Euclidean coordinate system; thus the positive direction of z-axis is away from the
imaging device. The origin of the object’s coordinate system is defined as the centroid of hand silhouette
image.
6.2.2.3 Finger
The x-axis is defined as the direction from the root to the tip of a finger as shown in Figure 2. The z-axis
is the direction perpendicular to the x-axis and away from the frontal side. The y-axis is perpendicular
both to the x and the z-axes with the direction following the right-handed Euclidean coordinate system.
The origin of the finger coordinate system is defined as the centroid of the finger silhouette image.
6.2.2.4 Back of hand
The y-axis of a back of the hand object is along the opposite direction of the middle finger, while the
x-axis is perpendicular to the y-direction along the tangent plane on the back of the hand as shown in
Figure 3. The z-axis shall be orthogonal to both the x-axis and the y-axis. The positive z-axis direction is
away from the imaging device, which follows the right-handed Euclidean coordinate system. The origin
of the object coordinate system is defined as the centroid of the hand silhouette image.
6.2.2.5 Coordinate systems for future modalities
This document shall reserve object coordinate system definitions for future technologies that may
utili
...
INTERNATIONAL ISO/IEC
STANDARD 39794-9
First edition
Information technology — Extensible
biometric data interchange formats —
Part 9:
Vascular image data
PROOF/ÉPREUVE
Reference number
ISO/IEC 39794-9:2021(E)
©
ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC 39794-9:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 39794-9:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Conformance . 2
6 Modality-specific information . 3
6.1 Capture recommendations . 3
6.1.1 Image area . 3
6.1.2 Illumination . 3
6.1.3 Normalization of projection . 3
6.1.4 Occlusion by opaque artifacts . 3
6.2 Image coordinate system considerations . 3
6.2.1 Standard pose . 3
6.2.2 Object coordinate system . 5
6.3 Image representation requirements . 6
6.3.1 General. 6
6.3.2 Pixel aspect ratio . 6
6.3.3 Bit-depth . 6
6.3.4 Spatial sampling rate . 6
7 Abstract data elements . 7
7.1 Purpose and overall structure . 7
7.2 Vascular image data block . 8
7.3 Version block . 8
7.4 Representation blocks . 8
7.5 Position . 8
7.6 Image data format . 8
7.6.1 Supported image data formats . 8
7.6.2 PGM format definition . . 8
7.7 Vascular image data . 9
7.8 Capture date/time block . . 9
7.9 Capture device block . 9
7.9.1 Model identifier block . 9
7.9.2 Capture device technology identifier . 9
7.9.3 Certification identifier block. 9
7.10 Quality blocks . 9
7.11 Scan resolution block .10
7.12 Pixel aspect ratio block .10
7.13 Bit-depth .10
7.14 Rotation angle .10
7.15 Image flip .10
7.16 Illumination .10
7.17 Imaging method .11
7.18 Image background .11
7.19 PAD data block.11
7.20 Segmentation blocks .11
7.21 Annotation blocks .11
7.22 Comment blocks .11
7.23 Vendor specific data blocks .12
8 Encoding .12
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ISO/IEC 39794-9:2021(E)
8.1 Tagged binary encoding .12
8.2 XML encoding .12
9 Registered format type identifiers .12
Annex A (normative) Formal specifications .13
Annex B (informative) Encording examples .25
Annex C (normative) Conformance test methodology .27
Bibliography .31
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ISO/IEC 39794-9:2021(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for
the different types of document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC
list of patent declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 37, Biometrics.
A list of all parts in the ISO/IEC 39794 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE v
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ISO/IEC 39794-9:2021(E)
Introduction
Biometric data interchange formats enable the interoperability of different biometric systems. The
first generation of biometric data interchange formats was published between 2005 and 2007 in the
first edition of the ISO/IEC 19794 series. From 2011 onwards, the second generation of biometric data
interchange formats was published in the form of second editions of the established parts and first
editions of a number of new parts of the ISO/IEC 19794 series. In the second generation of biometric
data interchange formats, new useful data elements such as data elements related to biometric sample
quality have been added, the header data structures have been harmonized across all parts of the
ISO/IEC 19794 series, and XML encoding has been added in addition to the binary encoding.
In anticipation of the future need for additional data elements and to avoid future compatibility issues,
ISO/IEC JTC 1/SC 37 has developed the ISO/IEC 39794 series as a third generation of biometric data
interchange formats, defining extensible biometric data interchange formats capable of including
future extensions in a defined manner. Extensible specifications in ASN.1 (Abstract Syntax Notation
One) and the distinguished encoding rules of ASN.1 form the basis for encoding biometric data in binary
tag-length-value formats. XML Schema Definitions form the basis for encoding biometric data in XML
(eXtensible Markup Language).
This third generation of vascular image data interchange formats complements ISO/IEC 19794-9:2007
and ISO/IEC 19794-9:2011.
This document is intended for those applications requiring the exchange of raw or processed vascular
images (for example, palm images) that are sometimes not necessarily limited in the amount of
resources available for data storage or transmitting time. It can be used for the exchange of scanned
vascular images containing detailed image pixel information.
Use of the captured or processed image allows interoperability among biometric systems relying on
pattern-based or other algorithms. Thus, data from the captured hand image offers the developer more
freedom in choosing or combining comparison algorithms. For example, an enrolment image can be
stored on a contactless chip located on an identification document. This allows future verification of the
holder of the document with systems that rely on pattern-based algorithms. Establishment of an image-
based representation of vascular information will not rely on pre-established definitions of patterns
or other types. It will provide implementers with the flexibility to accommodate images captured from
dissimilar devices, varying image sizes, spatial sampling rates, and different grey-scale depths. Use of
the vascular image will allow each vendor to implement their own algorithms to determine whether
two vascular records are from the same hand.
This document supports both binary and XML encoding, to support a spectrum of user requirements.
With XML, this document meets the requirements of modern IT architectures. With binary encoding,
this document is also able to be used in bandwidth or storage-constrained environments.
vi PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO/IEC 39794-9:2021(E)
Information technology — Extensible biometric data
interchange formats —
Part 9:
Vascular image data
1 Scope
This document specifies
— generic extensible data interchange formats for the representation of vascular image data: a tagged
binary data format based on an extensible specification in ASN.1 and a textual data format based on
an XML schema definition that are both capable of holding the same information,
— examples of data record contents,
— application specific requirements, recommendations, and best practices in data acquisition, and
— conformance test assertions and conformance test procedures applicable to this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 39794-1, Information technology — Extensible biometric data interchange formats — Part 1:
Framework
ISO/IEC 14495-1, Information technology — Lossless and near-lossless compression of continuous-tone still
images: Baseline — Part 1:
ISO/IEC 15444-1, Information technology — JPEG 2000 image coding system — Part 1: Core coding system
ISO/IEC 15948, Information technology — Computer graphics and image processing — Portable Network
Graphics (PNG): Functional specification
ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1) – Part 1: Specification of
basic notation
ISO/IEC 8825-1, Information technology – ASN.1 encoding rules – Part 1: Specification of Basic Encoding
Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 39794-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE 1
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ISO/IEC 39794-9:2021(E)
3.1
centroid
centre of gravity
Note 1 to entry: In this document, this term is used to define a unique location within a silhouette image that can
be assumed as the origin of a coordinate system.
3.2
dorsal
back side of a finger or a hand
3.3
ventral
palm side of a finger or a hand
3.4
vascular biometric image
captured raw or processed image that represents physical characteristics or traits of vascular pattern
used to recognize the identity or verify the claimed identity of an individual
4 Symbols and abbreviated terms
ICS implementation conformance statement
JPEG joint photographic experts group
MIR midrange infrared
NIR near infrared
nm nanometre
PGM portable gray map
PNG portable network graphics
ppcm pixels per centimetre
RGB red, green, blue color model
VIR vascular biometric image record
5 Conformance
A biometric data block (BDB) conforms to this document if it satisfies all of the requirements related to:
— its data structure, data values and the relationships between its data elements as specified
throughout Clauses 6, 7, 8 and Annex A, and
— the relationship between its data values and the input biometric data from which the biometric data
record was generated as specified throughout Clauses 6, 7, 8 and Annex A.
A system that produces biometric data records conforms to this document if all biometric data
records that it outputs conform to this document (as defined above) as claimed in the implementation
conformance statement (ICS) associated with that system. A system does not need to be capable of
producing biometric data records that cover all possible aspects of this document, but only those that
are claimed to be supported by the system in the ICS.
A system that uses biometric data records is conformant to this document if it can read, and use for the
purpose intended by that system, all biometric data records that conform to this document (as defined
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in the list above) as claimed in the ICS associated with that system. A system does not need to be capable
of using biometric data records that cover all possible aspects of this document, but only those that are
claimed to be supported by the system in an ICS.
Conformance test methodology shall be in accordance with Annex C.
6 Modality-specific information
6.1 Capture recommendations
6.1.1 Image area
Vascular pattern biometric technologies obtain images from different locations of the human body. The
technologies currently available employ images from the finger, back of the hand, and palm side of the
hand. The location used for imaging shall be specified in the format. Also, the direction (left/right) of hand
and/or finger index (thumb, index, middle, ring, and little) shall be specified. This document reserves
fields for future development of technologies potentially using different parts of the human body.
6.1.2 Illumination
For the capture of vascular biometric images, the skin is typically illuminated using NIR wavelengths in
the range of approximately 700 to 1 200 nm. The angle from the light source to the tangent plane of the
skin’s surface is not defined in VIR because technologies that use a reflectance image may use diffuse
illumination instead of direct illumination for the purpose of avoiding specular reflectance. Instead,
this document specifies that the image is either based on transparency or reflectance of the observed
biometric characteristic. Two or more wavelengths of the illumination light source may be specified in
the case that multiple different light sources are used for background masking.
6.1.3 Normalization of projection
The captured image shall be an orthographic projection of the body area being imaged. If the original
raw image is not orthographic to the body area, it shall be converted to an orthographically projected
one. Any major geometric distortion caused by the optical system shall also be eliminated prior to
creation of the VIR.
6.1.4 Occlusion by opaque artifacts
Some opaque artifacts, such as rings, tattoos, bandages, etc., can occlude vascular patterns. Using
images including occlusions should be avoided.
6.2 Image coordinate system considerations
6.2.1 Standard pose
6.2.1.1 General
This document defines the standard poses for capturing raw images of target body areas. Based
on these standard poses, object (target area of the human body) coordinate systems are defined as
described in subclause 6.2.2.
6.2.1.2 Palm
The palm area shall not be bent and each finger boundary shall be exposed to the camera. Fingers shall
be straight. An example of the standard pose of a palm is shown in Figure 1. In the standard pose, the
camera’s direction is parallel to the z-axis of the palm coordinate system defined in subclause 6.2.2.2.
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6.2.1.3 Finger
The standard pose is a straight finger. For clarity, the “frontal side” is defined as the ventral side of each
finger. An example of the standard pose of a finger is shown in Figure 2.
6.2.1.4 Back of the hand
The standard pose for the back of the hand shall be to position the hand with the dorsal side toward
the capture device with the tangent plane of the back of the hand in parallel with the image coordinate
space to produce an orthographic image of the back of the hand. An example of the standard pose of
the back of the hand is shown in Figure 3. In the standard pose, the camera’s direction is parallel to the
z-axis of the back of the hand coordinate system defined in subclause 6.2.2.3.
6.2.1.5 Standard poses for future modalities
This document shall reserve standard pose definitions of future technologies that can potentially
utilize different parts of the human body.
Key
x-axis perpendicular to the y-direction on the palm plane
y-axis along the opposite direction of the middle finger
z-axis perpendicular to the x-axis and away from the imaging device
NOTE The Euclidiean direction is right-handed.
Figure 1 — Standard pose and object coordinate system of palm vascular biometrics
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Key
x-axis direction from root to tip
y-axis perpendicular both to the x and the z-axes
z-axis perpendicular to the x-axis and away from the frontal side
a
frontal side
NOTE The Euclidiean direction is right-handed.
Figure 2 — Standard pose and object coordinate system of finger vascular biometrics
Key
x-axis perpendicular to the y-direction along the tangent plane on the back of the hand
y-axis along the opposite direction of the middle finger
z-axis orthogonal to both the x-axis and the y-axis and away from the imaging device
NOTE The Euclidiean direction is right-handed.
Figure 3 — Standard pose and object coordinate system of the back of the hand vascular
biometrics
6.2.2 Object coordinate system
6.2.2.1 General
The vascular image header record provides an optional field that specifies the degree of rotation of
the vascular image out of the standard pose. To effectively specify the rotation angle, the object (target
body) coordinate system for each vascular technology is defined in this subclause. All of the coordinate
systems are right-handed Euclidian coordinate systems.
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6.2.2.2 Palm
The y-axis of a palm object is along the opposite direction of the middle finger, while the x-axis is
perpendicular to the y-direction on the palm plane as shown in Figure 1. The z-axis shall be determined
by the right-handed Euclidean coordinate system; thus the positive direction of z-axis is away from
the imaging device. The origin of the object’s coordinate system is defined as the centroid of hand
silhouette image.
6.2.2.3 Finger
The x-axis is defined as the direction from the root to the tip of a finger as shown in Figure 2. The z-axis
is the direction perpendicular to the x-axis and away from the frontal side. The y-axis is perpendicular
both to the x and the z-axes with the direction following the right-handed Euclidean coordinate system.
The origin of the finger coordinate system is defined as the centroid of the finger silhouette image.
6.2.2.4 Back of hand
The y-axis of a back of the hand object is along the opposite direction of the middle finger, while the
x-axis is perpendicular to the y-direction along the tangent plane on the back of the hand as shown in
Figure 3. The z-axis shall be orthogonal to both the x-axis and the y-axis. The positive z-axis direction is
away from the imaging device, which follows the right-handed Euclidean coordinate system. The origin
of the object coordinate system is defined as the centroid of the hand silhouette image.
6.2.2.5 Coordinate systems for future modalities
This document shall reserve object coordinate system definitions for future technologies that may
utilize di
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