ISO/IEC 19794-15:2017

INTERNATIONAL ISO/IEC
STANDARD 19794-15
First edition
2017-05
Information technology — Biometric
data interchange format —
Part 15:
Palm crease image data
Technologies de l’information — Formats d’échange de données
biométriques —
Partie 15: Données relatives à l’image des lignes de la main
Reference number
©
ISO/IEC 2017
© ISO/IEC 2017, Published in Switzerland
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ii © ISO/IEC 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative reference . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Conformance . 2
6 Data conventions . 2
6.1 General . 2
6.2 Scan sequence . 3
7 Image capture requirements . 3
7.1 Spatial sampling rate . 3
7.2 Bit-depth . 4
7.3 Illumination . 4
7.4 Pixel aspect ratio . 4
7.5 Report structure . 4
7.6 Standard pose . 4
7.7 Occlusion by opaque artifacts . 5
8 Palm crease image format specification . 5
8.1 General data elements — Version . 5
8.2 Representation of specific data elements . 6
8.2.1 Overview . 6
8.2.2 Capture date and time . 6
8.2.3 Capture device type . 6
8.2.4 Quality block . 7
8.2.5 Image type . 7
8.2.6 Image width and image height . 7
8.2.7 Bit-depth . 8
8.2.8 Image position and property . 8
8.2.9 Image colour and compression . 9
8.2.10 Illumination type .10
8.2.11 Image background .10
8.2.12 Horizontal scan resolution .10
8.2.13 Vertical scan resolution .10
8.2.14 Pixel aspect ratio .10
8.3 Image data .10
8.4 Extended data .11
8.4.1 Extended data block function .11
8.4.2 Extended data block . .11
9 Registered format type identifiers .12
Annex A (normative) Conformance testing methodology .13
Annex B (normative) XML schema .15
Annex C (informative) XML sample .19
© ISO/IEC 2017 – All rights reserved iii

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.
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: w w w . i s o .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 19794 series can be found on the ISO website.
iv © ISO/IEC 2017 – All rights reserved

Introduction
Palm crease biometric technologies have existed for many years. Additionally, new technologies
employing palm crease images obtained from hands are emerging or under continuous improvement as
a result of new, state-of-the-art imaging devices for mobile applications or web services.
Currently however, palm crease biometric image information is being exchanged between the
equipment and devices from different vendors without standardized format is the problem. 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 document is to define a standard for the exchange of human palm crease biometric
image information. The standard defines specific attributes, a data record format for storing and
transmitting palm crease biometric images and certain attributes, a sample record, and conformance
criteria.
This document is intended for applications requiring the exchange of raw or processed palm crease
biometric images. It is intended for applications not limited by the amount of storage required. It is a
compromise or a trade-off between storage and quality and can be resolved by standardized format.
It enables various algorithms to identify or verify the palm crease biometric image data transferred
from other image sources. Currently, available palm crease biometric technologies that may utilize
this document for image exchange are technologies that use palm for mobile applications for identify
verification or web services.
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 palm
crease biometric image offers the developer more freedom in choosing or combining a comparison
subsystem
In this document, Annex A contains the conformance testing methodology and Annex B contains the
XML schema. Annex C contains the XML sample program.
© ISO/IEC 2017 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 19794-15:2017(E)
Information technology — Biometric data interchange
format —
Part 15:
Palm crease image data
1 Scope
This document specifies an image interchange format for biometric person identification or verification
technologies that utilize human palm crease biometric images and can be used for the exchange and
comparison of palm crease image data. It specifies a data record interchange format for storing,
recording, and transmitting palm crease biometric information from palm crease imaging. 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 document
can be recorded on machine-readable media or may be transmitted by data communication facilities.
2 Normative reference
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 10918 (all parts), Information technology — Digital compression and coding of continuous-tone
still images: JPEG File Interchange Format (JFIF)
ISO/IEC 15444 (all parts), Information technology — JPEG 2000 image coding system: Core coding system
ISO/IEC 14495 (all parts), Information technology — Lossless and near-lossless compression of continuous-
tone still images: Extensions
ISO/IEC 19785-1, Information technology — Common Biometric Exchange Formats Framework — Part 1:
Data element specification
ISO/IEC 19794-1:2011, Information technology — Biometric data interchange formats — Part 1:
Framework
ISO/IEC 19794-1:2011/Amd 1:2013, Conformance testing methodology
ISO/IEC 19794-1:2011/Amd 2:2015, Framework for XML encoding
1)
XML Schema Definition, W3C Recommendation, 2 May 2001
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19794-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
1) http:// www .w3 .org/ XML/ Schema
© ISO/IEC 2017 – All rights reserved 1

— ISO Online browsing platform: available at http:// www. iso. org/obp
3.1
palm crease biometric image
captured raw or processed image that represents physical characteristics or traits of palm crease
pattern used to recognize the identity or verify the claimed identity of an individual
4 Abbreviated terms
RGB Red, green, blue color model
XML eXtensible Markup Language
CBEFF Common Biometric Exchange Formats Framework
BDIR Biometric Data Interchange Record
BDB Biometric Data Block
BIR Biometric Information Record
ppcm pixels per centimetre
ppi pixels per inch
5 Conformance
A biometric data record conforms to this document 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 8 for the palm crease image record format of this document;
b) the relationship between its data values and the input biometric data from which the biometric
data record was generated, as specified throughout Clause 8 for the palm crease image record
format of this document.
A system that produces biometric data records is conformant 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 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 implementation conformance statement (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 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 document, but only those that are claimed to be supported by the system in an implementation
conformance statement (ICS).
6 Data conventions
6.1 General
The format specified in this document is a structural definition used to exchange palm crease image
data. In conformance with the rules described in ISO/IEC 19794-1, a palm crease image data should
be specified upon the definition of the BDIR or may be wrapped in the biometric data block (BDB) of a
CBEFF compliant structure (BIR) which is specified in ISO/IEC 19785-1.
2 © ISO/IEC 2017 – All rights reserved

6.2 Scan sequence
A raw palm crease image data conforming to this document 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 palm
crease. This document defines the scan direction of an imaging sensor as being along the positive x-axis
and y-axis for each palm crease biometric technology, assuming the target human body is positioned
in standard pose. The standard pose is defined in 7.6. If an image is scanned in a standard pose, the
x-axis and y-axis of the object coordinate system is in parallel with the x-axis 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. The z-axis of the object
coordinate system is not considered in this document because the palm crease is detected only in
2D space. Normalization process is necessary to search the features.
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 palm crease biometric image data may define the x-axis 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 factors such as the type of application, raw pixel
information, expected performance, and the physical size of the area to be captured for palm crease
extraction. This standard specifies a minimum spatial sampling rate of 40 pixels per centimetre (ppcm).
This value is the same as 100 pixel per inch (ppi). Figure 1 demonstrates two possible scanning areas:
whole hand and partial hand with curvature points.
a) Whole hand
© ISO/IEC 2017 – All rights reserved 3

b) Partial hand with curvature points
Figure 1 — Scanning area of human hand
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 palm crease biometric images, the skin is typically illuminated using natural light
or any means of lighting to support the capture of palm crease. The angle from the light source to the
tangent plane of the skin’s surface is not defined.
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 Report structure
Palm crease biometric technologies obtain images from the palm(s). Imaging location shall be specified
in the data format. The palm direction (left/right) shall be specified in the data format. This document
reserves fields for future development of technologies that may utilize different parts of human body.
7.6 Standard pose
The palm area shall not be bent and each distal crease 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.
Note that palm area shall not be bent, with exception to contact-less palm print technology which allows
slight bending of the hand area.
4 © ISO/IEC 2017 – All rights reserved

NOTE The Euclidean direction is right-handed.
Figure 2 — Standard pose and object coordinate system of palm crease biometrics
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.
7.7 Occlusion by opaque artifacts
Some opaque artefacts (such as rings, bandages, etc.) may occlude palm crease patterns. Using images
including occlusions should be avoided.
8 Palm crease image format specification
8.1 General data elements — Version
Table 1 — General data elements
Field Item type Valid values Mandatory/Optional
Major = 1,
Version VersionType Mandatory
Minor = 0
This version number shall consist of major version number and minor revision number. The format
given in ISO/IEC 19794-1:2011/Amd 2:2015 shall be used. The version number of this document shall
be major version 1 and minor revision 0.
© ISO/IEC 2017 – All rights reserved 5

8.2 Representation of specific data elements
8.2.1 Overview
Table 2 — Representation of specific data elements
Field Item type Valid values Mandatory/Optional
Capture date and time dateTime — Mandatory
Capture device type CaptureDeviceType See Table 3 Mandatory
Quality block cmn: QualityType See Table 5 Mandatory
Image type ImagePartType See Table 6 Mandatory
Image width Unsigned Short >0 Mandatory
Image height Unsigned Short >0 Mandatory
Bit-depth BitDepthType 7 or 16 Mandatory
Image position and
ImagePropertyType See Table 7 Mandatory
property
Image color and com-
ImageFormatType See Table 11 Mandatory
pression
Illumination type IlluminationType See Table 13 Mandatory
Image background defi-
BackgroundType See Table 14 Mandatory
nition
Horizontal scan resolu-
Unsigned Short <200 Mandatory
tion
Vertical scan resolution Unsigned Short <200 Mandatory
Pixel aspect ratio PicxelAspectRatioType See Table 15 Mandatory
8.2.2 Capture date and time
The date and time of capture date. This field shall be stated in coordinated universal time (UTC). The
format given in ISO/IEC 19794-1:2011/Amd 2:2015 shall be used for any absolute time values. This field
shall be the XML built-in type “dateTime”.
8.2.3 Capture device type
The capture device type field shall identify the product type that created the BDIR. It shall be assigned
by the registered product owner or other approved registration authority. If the capture device vendor
field is “Unreported”, then the capture device type identifier shall be “Unreported” also.
Table 3 — Capture device type
Field Item type Valid values Mandatory/Optional
Device ID cmn: RegistryIDType — Mandatory
Certification cmn: RegistryIDType — Mandatory
CaptureDeviceTechnology String See Table 4 Mandatory
The capture device technology field shall be encoded in string. This field shall indicate the class of
capture device technology used to acquire the captured biometric sample. See Table 4 for the list of
possible values.
6 © ISO/IEC 2017 – All rights reserved

Table 4 — Capture device technology value
Value
Unknown
NotSpecified
CCD/CMOS
8.2.4 Quality block
The quality block format is given in ISO/IEC 19794-1:2011/Amd 2:2015.
Table 5 — cmn: QualityType
Field Item type Valid values Mandatory/Optional
Algorithm cmn: RegistryIDType — Mandatory
0 to 100,
Score cmn: QualityScoreType Mandatory
or “QualityCalculationFailed”
8.2.4.1 Quality score
Quality score, as defined in ISO/IEC 19794-1, shall be a quantitative expression of the predicted
verification performance of the biometric sample. Valid values for quality score are integers between 0
and 100, where higher values indicate better quality. A value of “QualityCalculationFailed” is to handle a
special case. An entry of “QualityCalculationFailed” shall indicate a failed attempt to calculate a quality
score. Multiple quality scores calculated by the same algorithm (same vendor and algorithm) shall not
be present in a single representation.
8.2.4.2 Quality algorithm vendor
Quality algorithm vendor shall be
...