ISO/IEC 19794-9:2011

Information technology — Biometric data interchange formats — Part 9: Vascular image data

ISO/IEC 19794-9:2011 specifies an image interchange format for biometric person identification or verification technologies that utilize human vascular biometric images and can be used for the exchange and comparison of vascular image data. It specifies a data record interchange format for storing, recording, and transmitting vascular biometric information from one or more areas of the human body. It defines the contents, format, and units of measurement for the image exchange. The format consists of mandatory and optional items, including scanning parameters, compressed or uncompressed image specifications and vendor-specific information. Information compiled and formatted in accordance with ISO/IEC 19794-9:2011 can be recorded on machine-readable media or can be transmitted by data communication facilities.

Technologies de l'information — Formats d'échange de données biométriques — Partie 9: Données d'images vasculaires

General Information

• Status: Published
• Publication Date: 20-Sep-2011
• ICS: 35.040 - Information coding
• ICS: 35.240.15 - Identification cards. Chip cards. Biometrics
• Technical Committee: ISO/IEC JTC 1/SC 37 - Biometrics
• Drafting Committee: ISO/IEC JTC 1/SC 37/WG 3 - Biometric data interchange formats
• Current Stage: 9060 - Close of review
• Start Date: 03-Jun-2028

Relations

• Amended By: ISO/IEC 19794-9:2011/Amd 2:2015 - Information technology — Biometric data interchange formats — Part 9: Vascular image data — Amendment 2: XML Encoding and clarification of defects
• Effective Date: 10-Jul-2021
• Amended By: ISO/IEC 19794-9:2011/Amd 1:2013 - Information technology — Biometric data interchange formats — Part 9: Vascular image data — Amendment 1: Conformance testing methodology
• Effective Date: 26-Nov-2021
• Corrected By: ISO/IEC 19794-9:2011/Cor 1:2012 - Information technology — Biometric data interchange formats — Part 9: Vascular image data — Technical Corrigendum 1
• Effective Date: 08-May-2020
• Revises: ISO/IEC 19794-9:2007 - Information technology — Biometric data interchange formats — Part 9: Vascular image data
• Effective Date: 13-Mar-2010

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 19794-9
Second edition
2011-10-01


Information technology — Biometric data
interchange formats —
Part 9:
Vascular image data
Technologies de l'information — Formats d'échange de données
biométriques —
Partie 9: Données d'images vasculaires




Reference number
ISO/IEC 19794-9:2011(E)
©
ISO/IEC 2011

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ISO/IEC 19794-9:2011(E)

COPYRIGHT PROTECTED DOCUMENT


©  ISO/IEC 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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Published in Switzerland

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ISO/IEC 19794-9:2011(E)
Contents Page
Foreword . iv
Introduction . v
1  Scope . 1
2  Conformance . 1
3  Normative reference . 2
4  Terms and definitions . 2
5  Abbreviated terms . 2
6  Data conventions . 3
6.1  Byte and bit ordering . 3
6.2  Scan sequence . 3
7  Image capture requirements . 3
7.1  Spatial sampling rate . 3
7.2  Bit-depth . 3
7.3  Illumination . 3
7.4  Pixel aspect ratio . 4
7.5  Normalization of projection . 4
7.6  Image storage format . 4
7.7  Imaging area . 4
7.8  Standard pose . 5
7.9  Object coordinate system. 6
7.10  Occlusion by opaque artifacts . 7
8  Vascular image format specification . 7
8.1  Biometric Data Record . 7
8.2  General Header . 8
8.3  Representation header . 9
8.4  Extended data . 15
9  Registered Format Type Identifier . 18
Annex A (normative) Conformance Testing Methodology . 19
Annex B (informative) A sample image data packet . 20

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ISO/IEC 19794-9:2011(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. 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 shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 19794-9 was prepared by Technical Committee ISO/TC JTC1, Information technology,
Subcommittee SC 37, Biometrics.
This second edition cancels and replaces the first edition (ISO/IEC 19794-9:2007), Clause 8 and Annex A of
which have been technically revised.
ISO/IEC 19794 consists of the following parts, under the general title Information technology — Biometric data
interchange formats:
 Part 1: Framework
 Part 2: Finger minutiae data
 Part 3: Finger pattern spectral data
 Part 4: Finger image data
 Part 5: Face image data
 Part 6: Iris image data
 Part 7: Signature/sign time series data
 Part 8: Finger pattern skeletal data
 Part 9: Vascular image data
 Part 10: Hand geometry silhouette data
 Part 11: Signature/sign processed dynamic data
 Part 13: Voice Data
 Part 14: DNA data
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ISO/IEC 19794-9:2011(E)
Introduction
Vascular biometric technologies have existed for many years. Additionally, new technologies employing
vascular images obtained from various parts of the human body are emerging or under continuous
improvement as a result of new, state-of-the-art imaging devices. Some of them are being widely adopted as
reliable biometric modalities.
Currently however, little vascular biometric image information is being exchanged between the equipment and
devices from different vendors. This is due in part to the lack of standardized formats for information exchange
that would ensure interoperability among the various vendors.
The purpose of this part of ISO/IEC 19794 is to define a standard for the exchange of human vascular
biometric image information. It defines specific attributes, a data record format for storing and transmitting
vascular biometric images and certain attributes, a sample record, and conformance criteria.
This part of ISO/IEC 19794 is intended for applications requiring the exchange of raw or processed vascular
biometric images. It is intended for applications not limited by the amount of storage required. It is a
compromise or a trade-off between the resources required for data storage or transmission and the potential
for improved data quality/accuracy. Basically, it is to enable various algorithms to identify or verify the vascular
biometric image data transferred from other image sources. Currently available vascular biometric
technologies that may utilize this part of ISO/IEC 19794 for image exchange are technologies that use the
back of the hand, palm, and finger.
The use of captured source images can provide interoperability among and between vendors relying on
various different recognition or verification algorithms. Accordingly, data from the captured vascular biometric
image offers the developer more freedom in choosing or combining a comparison subsystem.

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INTERNATIONAL STANDARD ISO/IEC 19794-9:2011(E)

Information technology — Biometric data interchange
formats —
Part 9:
Vascular image data
1 Scope
This part of ISO/IEC 19794 specifies an image interchange format for biometric person identification or
verification technologies that utilize human vascular biometric images and may be used for the exchange and
comparison of vascular image data.
It specifies a data record interchange format for storing, recording, and transmitting vascular biometric
information from one or more areas of the human body. It defines the contents, format, and units of
measurement for the image exchange. The format consists of mandatory and optional items, including
scanning parameters, compressed or uncompressed image specifications and vendor-specific information.
Information compiled and formatted in accordance with this part of ISO/IEC 19794 can be recorded on
machine-readable media or may be transmitted by data communication facilities.
2 Conformance
A biometric data record conforms to this part of ISO/IEC 19794 if it satisfies all of the normative requirements
related to:
a) its data structure, data values, and the relationships between its data elements, as specified throughout
Clause 9 for the Vascular Image Record Format of this part of ISO/IEC 19794, and
b) the relationship between its data values and the input biometric data from which the biometric data record
was generated, as specified throughout Clause 9 for the Vascular Image Record Format of this part of
ISO/IEC 19794.
A system that produces biometric data records is conformant to this part of ISO/IEC 19794 if all biometric data
records that it outputs conform to this part of ISO/IEC 19794 (as defined above), as claimed in the
Implementation Conformance Statement associated with that system. A system does not need to be capable
of producing biometric data records that cover all possible aspects of this part of ISO/IEC 19794, but only
those that are claimed to be supported by the system in the Implementation Conformance Statement (ICS).
A system that uses biometric data records is conformant to this part of ISO/IEC 19794 if it can read, and use
for the purpose intended by that system, all biometric data records that conform to this part of ISO/IEC 19794
(as defined above), as claimed in the Implementation Conformance Statement associated with that system. A
system does not need to be capable of using biometric data records that cover all possible aspects of this part
of ISO/IEC 19794, but only those that are claimed to be supported by the system in an ICS.
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ISO/IEC 19794-9:2011(E)
3 Normative reference
The following referenced documents are indispensable for the application 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 10918-1, Information technology — Digital compression and coding of continuous-tone still images:
Requirements and guidelines
ISO/IEC 15444-1, Information technology — JPEG 2000 image coding system: Core coding system
ISO/IEC 14495-1, Information technology — Lossless and near-lossless compression of continuous-tone still
images: Baseline
ISO/IEC 19794-1:2011, Information technology — Biometric data interchange formats — Part 1: Framework
4 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19794-1 and the following apply.
4.1
centroid
centre of gravity
NOTE In this part of ISO/IEC 19794, it is used to define a unique location within a silhouette image that can be
assumed as the origin of a coordinate system.
4.2
dorsal
back side of a finger or a hand
4.3
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
4.4
vascular image header record
information contained in the header data structure of the vascular image data format as specified in this part of
ISO/IEC 19794
4.5
ventral
palm side of a finger or a hand
5 Abbreviated terms
nm nanometre
ppcm pixels per centimetre
VIR vascular biometric image record
RGB red, green, blue color model
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ISO/IEC 19794-9:2011(E)
6 Data conventions
6.1 Byte and bit ordering
The quantities in all records and vascular biometric image elements (pixel data), if represented as multibyte
quantities, are represented in big-endian format. That is, the more significant bytes of any multibyte quantity
are stored at lower addresses in memory than are the less significant bytes. The order for transmission shall
also be the most significant byte first and the least significant byte last. Within a byte, the order of transmission
shall be the most significant bit first and the least significant bit last. All numeric values are unsigned integer
quantities of fixed-length.
6.2 Scan sequence
A raw vascular image data conforming to this part of ISO/IEC 19794 is a two dimensional bit-mapped data
that scans an object from the upper left corner to the lower right corner within a region of interest of a human
body. This standard defines the scan direction of an imaging sensor as being along the positive x and y-axis
which is defined in clause 7.9 for each vascular biometric technology, assuming the target human body (finger,
back of the hand, or palm, etc.) is positioned in standard pose. The standard pose is defined in clause 7.8. If
an image is scanned in a standard pose, the x and y-axis of the object coordinate system is in parallel with the
x and y-axis of the image coordinate system. The x-direction of the image coordinate system is defined as the
scan line from left to right and the y-direction as being from the top to the bottom of the image. Additionally, in
a standard pose, the object z-axis is assumed to be in a direction parallel with the z-axis of the imaging device.
The scan sequence shall be raster scan order; that is, image pixels are acquired along the x-axis from top to
bottom in the y-direction. In order to map the object coordinate system to the image coordinate system without
further translation, each vascular biometric image data may define the x and y-axis origin which is not the pixel
location of the upper-left corner of the image. If the origin is not specifically defined, it shall be the pixel
location of the upper-left corner of the image.
7 Image capture requirements
7.1 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 may require higher spatial sampling
rate than a palm vein device due to difference size of the observed biometric characteristic. Therefore, this
standard does not specify the requirement of minimum spatial sampling rate. However, the spatial sampling
rate of the captured image shall be represented in terms of pixels per centimetre.
7.2 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.
7.3 Illumination
For the capture of vascular biometric images, the skin is typically illuminated using near-infrared wavelengths
in the range of approximately 700 to 1200 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
standard specifies that the image is either based on transparency or reflectance of the observed biometric
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ISO/IEC 19794-9:2011(E)
characteristic. Two or more wavelengths of illumination light source may be specified in the case that multiple
different light sources are used for background masking.
7.4 Pixel aspect ratio
The default pixel aspect ratio is 1:1. If the image is not of square pixels, the aspect ratio shall be described.
7.5 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.
7.6 Image storage format
The captured vascular image shall be transmitted and stored in one of several possible formats described in
the following paragraphs.
7.6.1 Raw format
The image is represented by a rectangular array of pixels with specified numbers of columns and rows. Each
pixel has at least 8 bits of information. There is no image header, and each pixel in a monochrome image is
represented by one or more bytes. Color images are represented as three samples per pixel, each comprised
of one or more bytes, representing red, green, and blue (RGB) intensities, in that order. The image is
organized in row-major order, with the lowest address corresponding to the upper left corner of the image. If
the pixel intensity value is represented by more than one byte, the bytes shall be stored in big-endian order.
7.6.2 Lossless compression format
If lossless compression is used the image data shall be compressed in accordance with the JPEG-LS lossless
compression algorithm specified in ISO/IEC 14495-1 or the JPEG2000 compression algorithm specified in
ISO/IEC 15444-1.
7.6.3 Lossy compression format
If lossy compression is used the image shall be compressed in accordance with the JPEG compression
algorithm specified in ISO/IEC 10918-1 or the JPEG2000 compression algorithm specified in ISO/IEC 15444-1.
If one of these compression algorithms is used, a compression factor of 4:1 or less is recommended.
7.6.4 Multichannel image format
Images may be acquired utilizing more than three colors or channels utilizing multichannel cameras. In this
case, pixel values may not be directly related to specific colors, rather they may be related to certain physical
characteristics. Images captured with more than three sensing channels shall be stored in accordance with
the JPEG2000 compression algorithm as specified in ISO/IEC 15444-1.
7.7 Imaging 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 part of ISO/IEC 19794 reserves
fields for future development of technologies that may utilize different parts of human body.
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ISO/IEC 19794-9:2011(E)
7.8 Standard pose
This part of ISO/IEC 19794 defines the standard poses to capture 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
clause 7.9.
7.8.1 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 1. In the standard pose, the camera’s direction is parallel to the z-axis of the back of
the hand coordinate system defined in clause 7.9.1.
7.8.2 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 2. In the standard pose, the camera’s
direction is parallel to the z-axis of the palm coordinate system defined in clause 7.9.2.
7.8.3 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 3.
7.8.4 Standard poses for future modalities
The format shall reserve standard pose definitions of future technologies that may utilize different part of the
human body.
z
z
x
x
y
y
Left hand Right hand

Figure 1 — Standard pose and object coordinate system of the back of the hand vascular biometrics.
The Euclidean direction is right-handed.
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ISO/IEC 19794-9:2011(E)
z
z
x
x
y
y

Figure 2 — Standard pose and object coordinate system of palm vascular biometrics. The Euclidean
direction is right-handed.
z
x
y
z-axis: (minus) normal to the frontal side
x-axis: the direction from root to tip
frontal side

Figure 3 — Standard pose and object coordinate system of finger vascular biometrics. The Euclidean
direction is right-handed.
7.9 Object coordinate system
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 clause. All of the coordinate systems are
right-handed Euclidian coordinate systems.
7.9.1 Back of the 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 1. 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.
7.9.2 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 2. 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.
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ISO/IEC 19794-9:2011(E)
7.9.3 Finger
The x-axis is defined as the direction from the root to the tip of a finger as shown in Figure 3. 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.
7.9.4 Coordinate systems for future modalities
The format shall reserve object coordinate system definitions for future technologies that may utilize different
parts of the human body.
7.10 Occlusion by opaque artifacts
Some opaque artifacts, such as rings, tattoos, bandages, etc. may occlude vascular patterns. Using images
including occlusions should be avoided.
8 Vascular image format specification
8.1 Biometric Data Record
Table 1 shows the basic structure of the vascular image biometric data record. A single data block starts with
a General Header, which contains general information on the data block such as the identification of the
image capture device and the format version. One or more vascular image blocks follow the record header.
Each image block consists of an image header and raw or compressed image data. The image header
contains all the image specific information such as the body location, rotation angle, and imaging conditions.
Each image header data shall be stored in big-endian format, where bit-level data definitions are specified as:
bit 1 shall be interpreted as the least significant bit (LSB).
Table 1 — Biometric Data Record
Description Length Note
Header used by all vascular biometric image providers.
General Header 15 bytes Information on format version, capture device ID, number of
representations contained in the VIR, etc.
Representation Representation header for the first representation. Contains all
40 bytes + 5*(#QualityBlocks)
header individual image specific information
{Representation length} – size
Image data Representation body
of Representation header
{ Extended Data Block
Extended data Extended data block
Length } + 4

 
 
 
Representation
40 bytes + 5*(#QualityBlocks) Representation header for the last representation
header
{Representation length} – size
Image data Representation body
of Representation header
{ Extended Data Block
Extended data Extended data block
Length } + 4
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Representation Representation

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ISO/IEC 19794-9:2011(E)
8.2 General Header
The General Header defines general information on the vascular images contained in the data block, such as
the format version number, total length of the record block, capture device identification, and the number of
images contained in the data block. The record header format is shown in Table 2.
Table 2 — General Header
Description Length Valid value Note
Format Identifier 4 bytes 56495200 'V' 'I' 'R' 00 (Vascular Image Record )
Hex Hex
This number indicates the second version of this
Version number 4 bytes 30323000
Hex
part of ISO/IEC 19794 used for constructing the
(‘0' '2' '0' 00 )
Hex
iris image data record and shall be placed in four
bytes. This version number shall consist of three
ASCII numerals by a zero byte as a NULL string
terminator
Length of record 4 bytes 00000000 to Total length of data record in bytes
Hex
FFFFFFFF
Hex
Number of representations 2 bytes 0000 to Number of images that a vascular image record
Hex
FFFF block contains
Hex
Certification flag 1 byte 00 This field indicates if each representation has a
Hex
certification block (zero or more certifications).
00 no certification available
Hex

8.2.1 Format identifier
The format identifier shall be recorded in four bytes. The format identifier shall consist of three characters
"VIR" followed by a zero byte as a NULL string terminator.
8.2.2 Version number
The number for the version of that part of ISO/IEC 19794 used for constructing the BDIR shall be placed in
four bytes. This version number shall consist of three ASCII numerals followed by a zero byte as a NULL
string terminator. The first and second character will represent the major version number and the third
character will represent the minor revision number. Upon approval of a specification, the initial version number
will be “020” – Version 2 revision 0.
8.2.3 Lengt
...