ISO/IEC 39794-9:2021

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 2021
© ISO/IEC 2021
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ii © ISO/IEC 2021 – All rights reserved

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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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
iv © ISO/IEC 2021 – All rights reserved

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

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

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

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
2 © ISO/IEC 2021 – All rights reserved

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.
© ISO/IEC 2021 – All rights reserved 3

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
4 © ISO/IEC 2021 – All rights reserved

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.
© ISO/IEC 2021 – All rights reserved 5

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 different parts of the human body.
6.3 Image representation requirements
6.3.1 General
Image representation requirements are dependent on various factors including the application, the
available amount of raw pixel information to retain or exchange, and targeted performance metrics.
As a result of these factors, the images represented will have characteristics based on the aspects
described below.
6.3.2 Pixel aspect ratio
The default pixel aspect ratio is 1:1. If the image is not made of square pixels, the aspect ratio shall be
described.
6.3.3 Bit-depth
The image shall have a dynamic range spanning at least 128 gray scale levels, allocating at least one
byte (8 bits) per intensity value and providing at least 7 bits of useful intensity information. The image
may utilize two or more bytes per gray scale value instead of one.
6.3.4 Spatial sampling rate
Image capture requirements are dependent on various factors such as the type of application, the
available amount of raw pixel information to be retained or exchanged, and the targeted performance.
Another factor to consider as a requirement for vascular biometric imaging is that the physical size of
the target body area where an application captures an image for the extraction of vascular pattern data
varies substantially (unlike other biometric modalities). For example, a finger vein biometric device can
require a higher spatial sampling rate than a palm vein device due to a difference in size of the observed
biometric characteristic. Therefore, this document does not specify the requirement of minimum
6 © ISO/IEC 2021 – All rights reserved

spatial sampling rate. However, the spatial sampling rate of the captured image shall be represented in
terms of pixels per centimetre (ppcm).
7 Abstract data elements
7.1 Purpose and overall structure
This clause describes the contents of data elements defined in this document. These descriptions are
independent of the encoding of the data elements. The presence of these data elements is specified in
Annex A.
The tagged binary encoding as well as the XML encoding is given in Clause 8 and Annex A, respectively.
In order to aid recognition of abstract values, the same lower camel-case notation is used for abstract
data elements in the ASN.1 module and in the XSD. The lower camel-case names are derived from the
abstract values given here.
The structure of the abstract data elements is additionally described for informative purposes in
Figure 4.
NOTE Figure 4 is not automatically generated and can only be viewed as an overview of the structure.
Figure 4 — Vascular image data block
© ISO/IEC 2021 – All rights reserved 7

7.2 Vascular image data block
Abstract values: See Figure 4 — Vascular image data block.
Contents: This data element is the container for all the data associated with the vascular
image.
7.3 Version block
Abstract values: See ISO/IEC 39794-1.
Contents: The edition number of this part of ISO/IEC 39794 shall be 3. The year shall be the
year of the publication of this document.
7.4 Representation blocks
Abstract values: See Figure 4 — Vascular image data block.
Contents: This data element is the container for all the data associated with the vascular
image, except for the version block information.
7.5 Position
Abstract values: See Annex A.
Contents: This data element establishes which vascular region is encoded in the image data.
For example, a right palm image is described with a position of “rightPalm” in an
ASN.1 encoding.
7.6 Image data format
7.6.1 Supported image data formats
Abstract values: Table 1 applies.
Contents: Vascular images shall be encoded using uncompressed or compressed formats. The
format used to encode the vascular image data shall match the format specified in
this data element. Table 1 lists the supported encoding algorithms and associated
parameters that may be used.
Table 1 — Image data formats
Abstract value Image data format Normative reference Maximum compression ratio
pgm PGM None None
jpeg2000lossy JPEG2000 (lossy) ISO/IEC 15444-1 4:1
jpeg2000lossless JPEG2000 (lossless) ISO/IEC 14495-1 None
png PNG ISO/IEC 15948 None
7.6.2 PGM format definition
A vascular image may be encoded in the Netpbm portable greyscale binary image format. The format
[4]
definition is defined as follows :
1) A "magic number" = “P5” for identifying the file type, followed by:
2) any Whitespace (blanks, TABs, CRs, LFs);
8 © ISO/IEC 2021 – All rights reserved

3) a width, formatted as ASCII characters in decimal;
4) any Whitespace (blanks, TABs, CRs, LFs);
5) a height, again in ASCII decimal;
6) any Whitespace (blanks, TABs, CRs, LFs);
7) the maximum grey value (Maxval), again in ASCII decimal (this shall be less than 65536, and more
than zero);
8) a single Whitespace character (usually a newline);
9) a raster of Height rows, in order from top to bottom. Each row consists of Width grey values, in
order from left to right. Each grey value is a number from 0 through Maxval, with 0 being black
and Maxval being white. Each grey value is represented in pure binary by either 1 or 2 bytes. If the
Maxval is less than 256, it is 1 byte. Otherwise, it is 2 bytes. The most significant byte is first.
7.7 Vascular image data
Abstract values: See Annex A.
Contents: This data element contains the encoded vascular image data.
7.8 Capture date/time block
See ISO/IEC 39794-1.
7.9 Capture device block
7.9.1 Model identifier block
See ISO/IEC 39794-1.
7.9.2 Capture device technology identifier
Abstract values: See Table 2.
Contents: This data element establishes the class of capture device technology used to ac-
quire the captured biometric sample. See Table 1 for a description of the abstract
values.
Table 2 — Capture device technology identifier
Abstract value Description
unknownTechnology Capture device technology information was not captured or has been lost.
otherTechnology Capture device technology information is known, but does not correspond to
any specified values.
CCD/CMOS camera Capture device using CCD or CMOS image sensor device.
7.9.3 Certification identifier block
See ISO/IEC 39794-1.
7.10 Quality blocks
See ISO/IEC 39794-1.
© ISO/IEC 2021 – All rights reserved 9

7.11 Scan resolution block
Abstract values: See Annex A.
Contents: This data element establishes the resolution of the vascular image. It consists of
two elements.
— the number of samples or pixels per unit distance, and
— the unit of measure for which the number of samples is related (either inch or
cm).
When pixel aspect ratio defined in 7.12 is not 1:1, this element shall specify
horizontal resolution and vertical resolution is calculated by the following formula.
SamplePerUnit of vertical = SamplePerUnit * aspectX / aspectY
7.12 Pixel aspect ratio block
Abstract values: See Annex A.
Contents: This element specifies the pixel aspect ratio.
7.13 Bit-depth
Abstract values: An integer value from 8 to 16.
Contents: This data element represents the number of bits per pixel in a greyscale image or
the number of bits per color components per pixel in an RGB image.
7.14 Rotation angle
Abstract values: An angle from 0 to 359.
Contents: This field specifies the rotation angle of the image around the z-axis in the object
coordinate system. The unit is degrees normalized to a 16-bit signed integer as (un-
signed short) round (65536*(angle%360) /360). This field is optional.
7.15 Image flip
Abstract values: See Annex A.
Contents: This element specifies whether or not the contained image is flipped, and if it is
flipped, in which way.
7.16 Illumination
Abstract values: See Annex A.
Contents: This element is an informative optional field that specifies the capture device’s
illumination source. The defined types are near infrared (NIR), midrange infrared
(MIR), and visible light source. The type of illumination shall be categorized based
on the wavelength of illumination source; that is, the wavelength of visible illumi-
nation is in the range of 380 nm through 780 nm, the wavelength of NIR is in the
range of 780 nm through 3 000 nm, and the wavelength of MIR is in the range of
[5]
3 000 nm through 50 000 nm .
10 © ISO/IEC 2021 – All rights reserved

7.17 Imaging method
Abstract values: See Annex A.
Contents: This element specifies whether the image has been captured by transparent or
reflectance illumination.
7.18 Image background
Abstract values: True or False.
Contents: This Boolean data element establishes whether the background of the image has
been processed or not. If background is processed, this field shall be true.
7.19 PAD data block
See ISO/IEC 39794-1.
7.20 Segmentation blocks
Abstract values: See Annex A.
Contents: This data element contains n-sided polygon coordinates that enclose segments of
the vascular image data. For example, the vascular image can be processed by vas-
cular segmentation software. The order of the vertex coordinates (when >2) shall
be in their consecutive order around the perimeter of the polygon, either clockwise
or counterclockwise. No two vertices may occupy the same location. The polygon
side defined by the last coordinate and the first coordinate shall complete the
polygon. The polygon shall be a simple, plane figure with no sides crossing and no
interior holes.
7.21 Annotation blocks
Abstract Values: See Table 3.
Contents: This format is provided to contain optional information about the vascular image
contained in a larger vascular image. The generic reasons that are supported by
this document are specified in Table 3.
Table 3 — Annotation reasons
Abstract value Description
amputated The vascular image region has been amputated, or is anatomically missing.
bandaged The vascular image region has a bandage on it rendering it not capturable.
physicallyChallenged Physical ailments, like extreme arthritis, prevent the capture of the vascular image region.
diseased The vascular image area suffers from the effects of a disease, rendering it not capturable.
unknown Annotation information was not captured or has been lost.
other Annotation information is known, but does not correspond to any specified values.
7.22 Comment blocks
Abstract values: Any string value (see Annex A for details).
Contents: This data element contains comment data associated with vascular image data.
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7.23 Vendor specific data blocks
Abstract values: See Annex A. As it consists of multiple internal data elements, the schema should be
examined directly in order to understand the possible positions.
Contents: This data element contains vendor specific proprietary data associated with the
vascular image. As this is an interoperable data interchange format, this data ele-
ment shall not be used to contain data that can be provided with other elements of
this document.
8 Encoding
8.1 Tagged binary encoding
The ASN.1 types as defined in A.1 which encode the abstract data elements of Clause 7 shall conform to
the ASN.1 standard ISO/IEC 8824-1 and to ISO/IEC 39794-1.
The tagged binary encoding of vascular image data shall be obtained by applying the ASN.1 Distinguished
Encoding Rules (DER) [ISO/IEC 8825-1] to a value of the type VascularImageBlock defined in the given
ASN.1 module. The DER encoding of each data object has three parts: tag octets that identify the data
object, length octets that give the number of subsequent value octets, and the value octets.
The ASN.1 module in A.1 can be retrieved from https:// standards .iso .org/ iso -iec/ 39794/ -9/ ed -1/ en/ .
See Annex B for the encoding sample.
8.2 XML encoding
The XML types as defined in A.2 which encode the abstract data elements of Clause 7 shall conform to
the XML standard ISO/IEC 39794-1.
An XML document encoding vascular image data shall obey the given XSD.
The XSD in Clause A.2 can be retrieved from https:// standards .iso .org/ iso -iec/ 39794/ -9/ ed -1/ en/ .
See Annex B for the encoding sample.
9 Registered format type identifiers
The registrations listed in Table 2 have been made with the Biometric Registration Authority to identify
the vascular image data interchange formats defined in this document. The format owner is ISO/IEC
JTC 1/SC 37 with the registered format owner identifier 257 (0101 ).
Hex
Table 4 — Format type identifiers
CBEFF BDB format
Short name Full object identifier
type identifier
{ iso(1) registration-authority(1) cbeff(19785) biometric-
g3-binary-
50 (0032 ) organization(0) jtc1-sc37(257) bdbs(0) g3-binary-
Hex
vascular-image
vascular-image(50) }
{ iso(1) registration-authority(1) cbeff(19785) biometric-
g3-xml-
51 (0033 ) organization(0) jtc1-sc37(257) bdbs(0) g3-xml-
Hex
vascular-image
vascular-image(51) }
12 © ISO/IEC 2021 – All rights reserved

Annex A
(normative)
Formal specifications
A.1 ASN.1 module for tagged binary encoding
ISO-IEC-39794-9-ed-1-v1 {iso(1) standard(0) iso-iec-39794(39794) part-9(9) ed-1(1) v1(1)
iso-iec-39794-9(0)}
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