ISO/IEC 2382-37:2022

INTERNATIONAL ISO/IEC
STANDARD 2382-37
Third edition
2022-03
Information technology —
Vocabulary —
Part 37:
Biometrics
Technologies de l'information — Vocabulaire —
Partie 37: Biométrie
Информационные технологии — Словарь —
Часть 37: Часть 37: Биометрия
Reference number
© ISO/IEC 2022
© ISO/IEC 2022
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© ISO/IEC 2022 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to general concepts . 1
3.2 Terms related to biometric systems . 2
3.3 Terms related to data in biometric systems . 4
3.4 Terms related to devices . 11
3.5 Terms related to functioning . 11
3.6 Terms related to interaction . 14
3.7 Terms related to personnel . 19
3.8 Terms related to application .23
3.9 Terms related to performance .23
Bibliography .30
Alphabetical Index.31
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© ISO/IEC 2022 – 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 https://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.
This third edition cancels and replaces the second edition (ISO/IEC 2382-37:2017), which has been
technically revised.
The main changes are as follows:
— modifications to some of the terms published in the 2017 edition; and
— addition of new terms related to biometric systems (starting from 37.02.08), data in biometric
systems (starting from 37.03.42), devices (37.04.02), interaction (starting from 37.06.33), personnel
(starting from 37.07.26) and performance (starting from 37.09.23).
A list of all parts in the ISO/IEC 2382 series can be found on the ISO and IEC websites.
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.
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© ISO/IEC 2022 – All rights reserved

Introduction
The main purpose of this document is to provide a systematic description of the concepts in the subject
field of biometrics and to clarify the use of the terms in this subject field. The subject field of biometrics
is broken down into sub-fields.
This document is addressed to biometrics standardizers and to users of these standards.
The terms defined in this document are to be understood within the context of the subject field of
biometrics. When terms exist in various subject fields, the relevant subject field is indicated in angle
brackets.
Words that are written in italics are defined in this document. Words that are written in upright font
are to be understood in their natural language sense. The authority for natural language use of terms
in this document is the Concise Oxford English Dictionary (COED), Thumb Index Edition (tenth edition,
revised, 2002).
The numbering of all terms in this document begins with “37” to indicate the Subcommittee of Joint
Technical Committee ISO/IEC JTC 1 that created the terms. This is consistent will all other parts of the
ISO/IEC 2382 series. The subsequent numerical heading for each entry within this document (37.xx)
represents the number of the highest-level category in the concept map in which the term primarily
falls. This is consistent with “Systematic Order” as described in ISO 10241-1:2011, 5.1.2, in which the
heading reflects the concept system. In the first edition of this document (ISO/IEC 2382-37:2012),
the third numerical designator (37.xx.yy) was also consistent with “Systematic Order”, moving from
most general to more specific terms within each highest-level category of the concept map. With the
development of the current edition of this document, the decision was made to append the new terms
in each category such that the numbering of the earlier terms inherited from the 2012 edition would
not change. This implies that the third numerical designator is now in “Mixed Order” as described in
ISO 10241-1:2011, 5.1.3.
So, terms are added to this document in batches for each updated version. These terms are added in
alphabetical order. This ensures that the numbers allocated to a term remain the same and that they
can be referred to consistently.
The terms in this document are listed under a number of general headings.
The layout follows the directions given in ISO 10241-1. Thus, the elements of an entry appear in the
following order:
— Entry number (mandatory)
— Preferred term(s) (mandatory)
— Admitted term(s)
— Deprecated term(s)
— Definition (mandatory)
— Example(s)
— Note(s) to entry
The alphabetical index includes preferred and admitted terms.
v
© ISO/IEC 2022 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 2382-37:2022(E)
Information technology — Vocabulary —
Part 37:
Biometrics
1 Scope
This document establishes a systematic description of the concepts in the field of biometrics pertaining
to recognition of human beings. This document also reconciles variant terms in use in pre-existing
International Standards on biometrics against the preferred terms, thereby clarifying the use of terms
in this field.
This document does not cover concepts (represented by terms) from information technology, pattern
recognition, biology, mathematics, etc. Biometrics uses such fields of knowledge as a basis.
In principle, mode-specific terms are outside of scope of this document.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminology 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/
3.1 Terms related to general concepts
37.01.01
biometric, adj
of or having to do with biometrics (37.01.03)
Note 1 to entry: The use of biometric as a noun, to mean for example, biometric characteristic (37.01.02), is
deprecated.
EXAMPLE 1 Incorrect usage #1: ICAO resolved that face is the biometric most suited to the practicalities of
travel documents.
EXAMPLE 2 Correct usage #1: ICAO resolved that face recognition is the biometric mode (37.02.05) most
suited to the practicalities of travel documents.
EXAMPLE 3 Incorrect usage #2: The biometric recorded in my passport is a facial image.
EXAMPLE 4 Correct usage #2: The biometric characteristic recorded in my passport is a facial image.
th
Note 2 to entry: Since the late 19 century the terms biometrics and biometry have been used with the general
meaning of counting, measuring and statistical analysis of any kind of data in the biological sciences including
the relevant medical sciences.
© ISO/IEC 2022 – All rights reserved

37.01.02
biometric characteristic
DEPRECATED biometric
biological and behavioural characteristic of an individual from which distinguishing, repeatable
biometric features (37.03.11) can be extracted for the purpose of biometric recognition (37.01.03)
EXAMPLE Examples of biometric characteristics are Galton ridge structure, face topography, facial skin
texture, hand topography, finger topography, iris structure, vein structure of the hand, ridge structure of the
palm, retinal pattern, handwritten signature dynamics, etc.
37.01.03
biometric recognition
biometrics
automated recognition of individuals based on their biological and behavioural characteristics
Note 1 to entry: In the field of biometrics (as defined in this document), “Individual" is restricted in scope to refer
only to humans.
Note 2 to entry: The general meaning of biometrics encompasses counting, measuring and statistical analysis of
any kind of data in the biological sciences including the relevant medical sciences.
Note 3 to entry: Biometric recognition encompasses biometric verification (37.08.03) and biometric identification
(37.08.02).
Note 4 to entry: Automated recognition implies that a machine-based system is used for the recognition either
for the full process or assisted by a human being.
Note 5 to entry: Behavioural and biological characteristics cannot be completely separated which is why
the definition uses ‘and’ instead of ‘and/or’. For example, a fingerprint image results from the biological
characteristics of the finger ridge patterns and the behavioural act of presenting the finger.
Note 6 to entry: Use of 'authentication' as a synonym for “biometric verification or biometric identification” is
deprecated; the term biometric recognition is preferred.
3.2 Terms related to biometric systems
37.02.01
biometric capture subsystem
biometric capture devices (37.04.01) and any sub-processes required to execute a biometric capture
process (37.05.02)
Note 1 to entry: In some biometric systems (37.02.03), converting a signal from a biometric characteristic (37.01.02)
to a captured biometric sample (37.03.25) can include multiple components such as a camera, photographic paper,
printer, digital scanner, ink and paper.
Note 2 to entry: A biometric capture subsystem can consist of only a single biometric capture device.
37.02.02
biometric identification system
system that aims to perform biometric identification (37.08.02)
37.02.03
biometric system
system for the purpose of the biometric recognition (37.01.03) of individuals based on their behavioural
and biological characteristics
Note 1 to entry: A biometric system will contain both biometric (37.01.01) and non-biometric components.
37.02.04
biometric verification system
system that aims to perform biometric verification (37.08.03)
© ISO/IEC 2022 – All rights reserved

37.02.05
mode
DEPRECATED biometric, noun
combination of a biometric characteristic (37.01.02) type, a sensor type and a processing method
Note 1 to entry: The processing algorithm may contain multiple methods, details of which are not necessarily
externally apparent. Thus, a biometric system (37.02.03) is considered as using one processing method, until it is
otherwise specified.
Note 2 to entry: Determining what constitutes a single type of sensor, processing method or biometric
characteristic will depend on convention. For example, current convention is that images of ridge patterns
from both thumbs and fingers represent a single biometric characteristic type, i.e. fingerprints. With respect to
sensors, infrared and optical bandwidth sensors are considered different types, but optical bandwidth sensors
are considered a single type despite imaging red, green and blue bandwidths.
37.02.06
multimodal
multiple in at least two out of three constituents of a mode (37.02.05) in a single biometric system
(37.02.03)
Note 1 to entry: Multiple implies difference in type.
37.02.07
system participation ratio
proportion of individuals eligible to use the system who do use the system
Note 1 to entry: Enrolled individuals are a subset of eligible individuals.
Note 2 to entry: This term is used to express the extent of take-up and use of a biometric system (37.02.03).
37.02.08
biometric fusion
combination of biometric (37.01.01) information from different sources to inform a comparison decision
(37.03.26) within a biometric transaction (37.06.45)
Note 1 to entry: The sources can be at the signal, feature, score, rank or decision level.
37.02.09
monobiometric system
biometric system (37.02.03) of which all of the following components are required to be singular:
biometric capture subsystem (37.02.01), biometric instance (37.03.46), biometric characteristic (37.01.02)
type, biometric algorithm (37.04.02) and biometric presentation (37.06.07)
Note 1 to entry: This term is needed for completeness. It can be the case that few systems are monobiometric, as
multiple instances and multipresentations are normally allowed.
37.02.10
multibiometric system
biometric system (37.02.03) of which at least one of the following components is required to be multiple:
biometric capture subsystem (37.02.01), biometric instance (37.03.46), biometric characteristic (37.01.02)
type, biometric algorithm (37.04.02) or biometric presentation (37.06.07)
37.02.11
multipresentation system
system that accepts multiple interactions of the biometric capture subject (37.07.03) with the biometric
capture subsystem (37.02.01) to obtain signals from a biometric characteristic (37.01.02) needed for a
single transaction (37.06.45)
Note 1 to entry: The interaction is seen from the perspective of the biometric capture subject.
© ISO/IEC 2022 – All rights reserved

37.02.12
multibiometric, adj
based on multiple types of biometric characteristics (37.01.02)
EXAMPLE A biometric system that is based on two or more biometric characteristic types such as two or
more of face, voice, finger, iris, retina, hand geometry, signature/sign, keystroke, lip movement, gait, vein, DNA,
ear, foot, scent, etc.
3.3 Terms related to data in biometric systems
37.03.01
anonymized biometric data record
biometric data record (37.03.08) purposely disassociated from individual metadata
Note 1 to entry: The biometric data (37.03.06) within the biometric data record ultimately remains attributable
to an individual.
37.03.02
biometric application database
database of biometric data (37.03.06) and associated metadata developed from and supporting the
operation of a biometric (37.01.01) application
Note 1 to entry: The metadata may include transaction (37.06.45) history; authorizations (e.g. age) of the
biometric data subject (37.07.05); and archived biometric data.
Note 2 to entry: The term application includes the policies that govern the operation of the biometric system
(37.02.03) and evidence of that operation.
37.03.03
biometric application decision
decision to perform an action at the application level based on the results of a biometric (37.01.01)
process
Note 1 to entry: The application decision may include more than a comparison (37.05.07) process. For example,
a biometric capture process (37.05.02) may show that there are no biometric characteristics (37.01.02) to capture
and a decision can be made on this before any biometric characteristics are compared.
Note 2 to entry: Biometric application decisions can be made on the basis of complex policies involving both
biometric data (37.03.06) and non-biometric data.
37.03.04
biometric candidate
biometric reference identifier (37.03.19) of a biometric reference (37.03.16) in the biometric reference
database (37.03.17) determined to be sufficiently similar to the biometric probe (37.03.14) to warrant
further analysis
Note 1 to entry: Identification systems can be configured to return a fixed number of the most similar candidates
and, in other cases, the system could be configured to return candidates with biometric candidate scores
(37.03.24) that exceed a threshold (37.03.36).
37.03.05
biometric candidate list
set of zero, one or more biometric candidates (37.03.04)
Note 1 to entry: The biometric candidate list can be tentative if it is to be reduced by further processing.
37.03.06
biometric data
biometric sample (37.03.21) or aggregation of biometric samples at any stage of processing
EXAMPLE Biometric reference (37.03.16), biometric probe (37.03.14), biometric feature (37.03.11) or biometric
property (37.03.15).
© ISO/IEC 2022 – All rights reserved

Note 1 to entry: Biometric data need not be attributable to a specific individual, e.g. Universal Background
Models.
37.03.07
biometric database
database of biometric data record(s) (37.03.08)
37.03.08
biometric data record
data record containing biometric data (37.03.06)
Note 1 to entry: A biometric data record may include non-biometric data.
37.03.09
biometric enrolment database
database of biometric enrolment data record(s) (37.03.10)
Note 1 to entry: A database of biometric data (37.03.06) not attributable to biometric data subjects (37.07.05)
is a biometric database (37.03.07), but not a biometric enrolment database, e.g. data for Universal Background
Models.
Note 2 to entry: The biometric enrolment database can optionally contain the biometric reference database
(37.03.17). Separation of the databases can be required due to security, privacy, legislation, architecture,
performance, etc.
Note 3 to entry: A single biometric reference (37.03.16) (e.g. a fingerprint on a storage card) can be considered as
a biometric enrolment database in some transactions (37.06.45).
37.03.10
biometric enrolment data record
data record attributed to a biometric data subject (37.07.05), containing non-biometric data and
associated with biometric reference identifier(s) (37.03.19)
Note 1 to entry: Data can be updated after enrolment.
Note 2 to entry: The biometric enrolment data record will either contain biometric reference data record(s)
(37.03.18) or pointer(s) to biometric reference data record(s).
Note 3 to entry: The associated biometric reference (37.03.16) can be null (for example, biometric enrollee
(37.07.06) lacks the biometric characteristic (37.01.02) or biometric capture process (37.05.02) is pending.
37.03.11
biometric feature
number or label extracted from biometric samples (37.03.21) and used for comparison (37.05.07)
Note 1 to entry: The set of numbers or labels are the output of a completed biometric feature extraction (37.05.04).
Note 2 to entry: The use of this term should be consistent with its use by the pattern recognition and mathematics
communities.
Note 3 to entry: A biometric feature set can also be considered a processed biometric sample.
Note 4 to entry: Biometric features may be extracted from an intermediate biometric sample (37.03.30).
Note 5 to entry: Filters applied to biometric samples are not themselves biometric features. However, the output
of the filter applied to the biometric samples can be. Therefore, eigenfaces are not biometric features, for example.
37.03.12
biometric identification decision
comparison decision (37.03.26) as to whether a biometric reference(s) (37.03.16) of a particular biometric
data subject (37.07.05) is in a biometric reference database (37.03.17)
Note 1 to entry: Return of a biometric candidate list (37.03.05) is not considered a biometric identification
decision.
© ISO/IEC 2022 – All rights reserved

Note 2 to entry: A positive biometric identification (37.08.02) process is inferred from the output of a biometric
reference identifier (37.03.19).
37.03.13
biometric model
stored function generated from biometric data (37.03.06)
EXAMPLE Examples of biometric models could be a Hidden Markov Model, Gaussian Mixture Model or an
Artificial Neural Network.
Note 1 to entry: In most occasions the biometric model is a stored function which is dependent on the biometric
data subject (37.07.05).
Note 2 to entry: The function may be determined through training.
Note 3 to entry: A biometric model may involve intermediate processing similar to biometric feature extraction
(37.05.04).
37.03.14
biometric probe
biometric query
biometric sample (37.03.21) or biometric feature (37.03.11) set input to an algorithm for comparison
(37.05.07) to a biometric reference(s) (37.03.16)
Note 1 to entry: In some comparisons a biometric reference can potentially be used as the subject of the
comparison with other biometric references or incoming biometric samples used as the objects of the
comparisons. For example, in a duplicate enrolment check a biometric reference will be used as the subject for
comparisons against all other biometric references in the database.
Note 2 to entry: Typically, in a comparison process, incoming biometric samples serve as the subject of
comparisons against objects stored as biometric references in a database.
37.03.15
biometric property
descriptive attributes of the biometric data subject (37.07.05) estimated or derived from the biometric
sample (37.03.21) by automated means
EXAMPLE Fingerprints can be classified by the biometric properties of ridge-flow, i.e. arch, whorl and loop
types. Estimates of age or gender (37.07.31) from face recognition would also be biometric properties.
37.03.16
biometric reference
one or more stored biometric samples (37.03.21), biometric templates (37.03.22) or biometric models
(37.03.13) attributed to a biometric data subject (37.07.05) and used as the object of biometric
comparison (37.05.07)
EXAMPLE Face image stored digitally on a passport; fingerprint minutiae template on a National ID card or
Gaussian Mixture Model for speaker recognition, in a database.
Note 1 to entry: A biometric reference may be created with implicit or explicit use of auxiliary data, such as
Universal Background Models.
Note 2 to entry: The subject/object labelling in a comparison can be arbitrary. In some comparisons a biometric
reference can potentially be used as the subject of the comparison with other biometric references or incoming
biometric samples and input to a biometric algorithm (37.04.02) for comparison. For example, in a duplicate
enrolment check a biometric reference will be used as the subject for comparison against all other biometric
references in the database.
© ISO/IEC 2022 – All rights reserved

37.03.17
biometric reference database
database of biometric reference data records (37.03.18)
Note 1 to entry: The biometric reference database may be a subset of the biometric enrolment database (37.03.09),
or it may be a separate database. Separation of the databases may be required due to security, privacy, legislation,
architecture, performance, etc.
37.03.18
biometric reference data record
indexed data record containing biometric reference(s) (37.03.16)
Note 1 to entry: There is not necessarily a one to one correspondence between biometric reference data records
and biometric data subjects (37.07.05). For example, a single biometric data subject can have several reference
data records and in some applications a single biometric reference data record can be associated with multiple
enrolments of a biometric data subject.
37.03.19
biometric reference identifier
pointer to a biometric reference data record (37.03.18) in the biometric reference database (37.03.17)
37.03.20
biometric representation
biometric sample (37.03.21) or biometric feature (37.03.11) set
Note 1 to entry: This term is used in the ISO/IEC 19794 series and the ISO/IEC 39794 series for labelling a sub-
record in a biometric data record (37.03.08).
37.03.21
biometric sample
analogue or digital representation of biometric characteristics (37.01.02) prior to biometric feature
extraction (37.05.04)
EXAMPLE A record containing the image of a finger is a biometric sample.
37.03.22
biometric template
reference biometric feature set
set of stored biometric features (37.03.11) comparable directly to a biometric probe (37.03.14)
EXAMPLE A record containing a set of finger minutiae is a biometric template.
Note 1 to entry: A biometric reference (37.03.16) consisting of an image, or other captured biometric sample
(37.03.25), in its original, enhanced or compressed form, is not a biometric template.
Note 2 to entry: The biometric features (37.03.11) are not considered to be a biometric template unless they are
stored for reference.
37.03.23
biometric verification decision
comparison decision (37.03.26) determining the validity of a biometric claim (37.06.04) in a verification
transaction (37.06.21)
37.03.24
biometric candidate score
comparison score (37.03.27) for a biometric candidate (37.03.04)
37.03.25
captured biometric sample
DEPRECATED raw biometric sample
biometric sample (37.03.21) resulting from a biometric capture process (37.05.02)
© ISO/IEC 2022 – All rights reserved

37.03.26
comparison decision
determination of whether the biometric probe(s) (37.03.14) and biometric reference(s) (37.03.16) have
the same biometric (37.01.01) source, based on a comparison score(s) (37.03.27), a decision policy(ies)
including a threshold (37.03.36) and possibly other inputs
Note 1 to entry: A match (37.03.31) is a positive comparison decision. A non-match (37.03.33) is a negative
comparison decision. A decision of "undetermined" may sometimes be given.
37.03.27
comparison score
DEPRECATED matching score
numerical value (or set of values) resulting from a comparison (37.05.07)
Note 1 to entry: A higher score does not necessarily mean more similar.
37.03.28
dissimilarity score
distance score
comparison score (37.03.27) that decreases with similarity
Note 1 to entry: Unlike a distance score, a dissimilarity score does not have to meet the mathematical definition
of a metric on a set.
37.03.29
fraudulent biometric enrolment data record
biometric enrolment data record (37.03.10) created or modified for the purpose of supporting wrongful
or criminal activity
Note 1 to entry: Records that are inadvertently erroneous or created for test purposes are not considered
fraudulent.
37.03.30
intermediate biometric sample
biometric sample (37.03.21) resulting from intermediate biometric sample processing (37.05.09)
EXAMPLE Biometric samples that have been cropped, down-sampled, compressed, or enhanced are
examples of intermediate biometric samples.
37.03.31
match, noun
comparison decision (37.03.26) stating that the biometric probe(s) (37.03.14) and the biometric reference
(37.03.16) are from the same source
Note 1 to entry: Historically, the word match has been used as a verb to indicate the act of comparison (37.05.07)
and decision making. As ‘match’ is the decision coming out of the comparison process, its use as a verb is
deprecated in favour of compare.
37.03.32
mated, adj
based on a paired biometric probe (37.03.14) and biometric reference (37.03.16) that are from the same
biometric characteristic (37.01.02) of the same biometric data subject (37.07.05)
Note 1 to entry: While ‘match’ (37.03.31) is the result of a comparison decision (37.03.26), ‘mated’ is a statement,
based on non-biometric information, concerning the origin of the source of the biometric probe and the biometric
reference.
37.03.33
non-match, noun
comparison decision (37.03.26) stating that the biometric probe(s) (37.03.14) and the biometric reference
(37.03.16) are not from the same source
© ISO/IEC 2022 – All rights reserved

37.03.34
non-mated, adj
based on a paired biometric probe (37.03.14) and biometric reference (37.03.16) that are not from the
same biometric characteristic (37.01.02) of the same biometric data subject (37.07.05)
Note 1 to entry: While ‘non-match' (37.03.33) is the result of a comparison decision (37.03.26), ‘non-mated’ is a
statement, based on non-biometric information, concerning the origin of the source of the biometric probe and
the biometric reference.
37.03.35
similarity score
comparison score (37.03.27) that increases with similarity
37.03.36
threshold, noun
numerical value (or set of values) at which a decision boundary exists
37.03.37
unidentified biometric data
biometric data (37.03.06) whose biometric data subject (37.07.05) is currently unknown
37.03.38
conformant biometric reference rate
proportion of biometric enrolment data records (37.03.10) containing biometric references (37.03.16)
conformant (37.06.31) with system policy
Note 1 to entry: Some biometric systems (37.02.03) require the enrolment of all applicants regardless of the
availability of acquirable biometric characteristics (37.01.02). This ratio, which depends upon system capabilities
and policies regulating acquisition of biometric samples (37.03.21), characterizes the percentage of a given
enrolled population that has conformant biometric references in the biometric enrolment data records.
Note 2 to entry: This can be enumerated individually for enrolment subsystems with distinct enrolment policies.
37.03.39
biometric reference rate
proportion of biometric enrolment data records (37.03.10) that contain a biometric reference (37.03.16)
Note 1 to entry: Some biometric systems (37.02.03) require the enrolment of all applicants regardless of the
availability of acquirable biometric characteristics (37.01.02). This ratio, which depends upon system capabilities
and policies regulating acquisition of biometric samples (37.03.21), characterizes the percentage of a given
enrolled population that has any biometric references in the biometric enrolment data records.
Note 2 to entry: This can be enumerated individually for enrolment subsystems with distinct enrolment policies.
Note 3 to entry: Non-conformant references are considered as references.
37.03.40
enrolment eligibility ratio
proportion of enrolment applications that are deemed eligible by policy for enrolment
Note 1 to entry: The closer this ratio is to unity, the more aligned the applicants are to the eligible population.
37.03.41
reference ageing
DEPRECATED template ageing
change in error rates with respect to a fixed reference caused by time-related changes in the biometric
characteristic (37.01.02)
Note 1 to entry: Error rates generally increase with the age of the reference.
Note 2 to entry: Reference ageing can include sample ageing, template ageing and model ageing.
© ISO/IEC 2022 – All rights reserved

37.03.42
acquired biometric sample
captured biometric sample (37.03.25) assessed as suitable for subsequent biometric feature extraction
(37.05.04) and comparison (37.05.07)
37.03.43
acquisition profile
list of attributes pertaining to the collection environment, the data capture subsystem, the biometric
data subject (37.07.05), subsequent processing and management of the data
Note 1 to entry: Acquisition profiles are dependent on the modality.
37.03.44
biometric application conformance profile
listing of standards to be applied for a specific function or task
Note 1 to entry: Application profiles (37.03.48) identify (37.08.05) the use of particular options in base standards
and provide a basis for conformant applications and interoperability of systems.
37.03.45
biometric data breach
unauthorized access, disclosure, alteration, transmission or processing of the biometric data (37.03.06)
of an individual
Note 1 to entry: This definition does not apply to collection and storage even if unauthorized.
Note 2 to entry: Authorization is a jurisdictional responsibility (e.g. a government or a data subject) and limited
to the purposes for which the data was collected.
37.03.46
biometric instance
occurrence of a biometric characteristic (37.01.02)
Note 1 to entry: A human hand typically has five instances of a fingerprint biometric characteristic.
Note 2 to entry: Multiple presentations of the same spoken or written phrase is a single instance.
37.03.47
multi-instance
requiring two or more instances of a biometric characteristic (37.01.02)
Note 1 to entry: The typical human hand contains more than one instance of a fingerprint biometric characteristic.
37.03.48
profile
list of attributes pertaining to an entity or a class of entities
37.03.49
pseudonymized biometric data record
biometric data record (37.03.08) purposely dis-associated from non-biometric personally identifiable
information
Note 1 to entry: The biometric data (37.03.06) within the biometric data record ultimately remain attributable to
an individual.
Note 2 to entry: This definition is consistent with the term pseudonymization in the EU General Data Protection
Regulation 2016/679.
37.03.50
normalize
rescale of values for comparison (37.05.07) against a common or standardized scale
Note 1 to entry: Rescaling can be linear or non-linear.
© ISO/IEC 2022 – All rights reserved

Note 2 to entry: The standardized scale may specify a range for the scores, a polarity or a distribution.
3.4 Terms related to devices
37.04.01
biometric capture device
device that collects a signal from a biometric characteristic (37.01.02) and converts it to a captured
biometric sample (37.03.25)
Note 1 to entry: A signal can be generated by the biometric characteristic or generated elsewhere and affected by
the biometric characteristic, for example, face illuminated by incident light.
Note 2 to entry: A biometric capture device can be any piece of hardware (and supporting software and firmware).
Note 3 to entry: A biometric capture device may comprise components such as an illumination source, one or
more sensors, etc.
37.04.02
biometric algorithm
set of instructions and rules for processing biometric samples (37.03.21)
Note 1 to entry: The complete processing of biometric signals and data may involve: signal detection,
segmentation, biometric feature extraction (37.05.04), quality assessment, biometric model (37.03.13) generation,
biometric template (37.03.22) generation, comparison (37.05.07), biometric comparison decision (37.03.26),
compression, decompression, etc.
3.5 Terms related to functioning
37.05.01
biometric acquisition process
biometric capture process (37.05.02) and additional processing to attempt to produce a suitable biometric
sample(s) (37.03.21) in accordance with the defined policy
Note 1 to entry: In addition to the biometric capture process, a biometric acquisition process may include
segmentation, quality control and other pre-processing steps.
Note 2 to entry: A biometric acquisition process may produce multiple biometric samples from a single biometric
capture (37.06.03) and each biometric sample is attributable to a single biometric characteristic (37.01.02). For
example, four fingerprints in a slap image and three segmented face samples of the three people in a captured
photograph.
Note 3 to entry: The policy defines the end point of the biometric acquisition process.
37.05.02
biometric capture process
series of actions undertaken to effect a biometric capture (37.06.03)
EXAMPLE To obtain an International Civil Aviation Organisation (ICAO) compliant passport photograph, the
biometric capture subject (37.07.03) will have to undertake a number of steps e.g. remove glasses, look directly at
the camera and not smiling, etc. These steps are the biometric capture process.
Note 1 to entry: Not all biometric capture processes result in a biometric capture.
Note 2 to entry: The biometric capture process may involve a single biometric capture device (37.04.01) or may be
distributed over time and space in such a way that there is no single definable biometric capture device.
© ISO/IEC 2022 – All rights reserved

37.05.03
biometric enrolment
DEPRECATED registration
act of creating and storing a biometric enrolment data record (37.03.10) in accordance with an enrolment
policy
Note 1 to entry: Registration has a different meaning in the signal processing community and its use is therefore
deprecated in biometrics (37.01.03) in favour of enrolment.
Note 2 to entry: Enrolment in a biometric system (37.02.03) can in some cases not involve storage of biometric
data (37.03.06), for example, when biometric data from an enrollee (37.07.06) cannot be acquired.
37.05.04
biometric feature extraction
process applied to a biometric sample (37.03.21) with the intent of isolating and outputting repeatable
and distinctive numbers or labels which can be compared to those extracted from other biometric
samples
Note 1 to entry: The creation of filters to be applied to biometric samples is not biometric feature extraction.
However, the application of filters to biometric samples can be. Therefore, for example, the creation of eigenfaces
is not biometric feature extraction.
Note 2 to entry: Repeatable implies low variation between outputs generated from biometric samples of the same
biometric data subject (37.07.05).
Note 3 to entry: Distinctive implies high variation between outputs generated from biometric samples of different
biometric data subjects.
Note 4 to entry: Biometric feature extraction can fail.
Note 5 to entry: Biometric feature extraction can be applied to an intermediate biometric sample (37.03.30).
37.05.05
biometric reference adaptation
automatic incremental updating of a biometric reference (37.03.16)
Note 1 to entry: Biometric reference adaptation can be used to improve performance (e.g. adapting the reference
to take account of variability of an individual's biometric characteristics (37.01.02) and to mitigate performance
degradation (e.g. due to changes in biometric characteristics over time).
37.05.06
biometric search
examination of a biometric reference database (37.03.17) against a biometric probe (37.03.14) to return
either a biometric candidate list (37.03.05) or a comparison decision (37.03.26) that the biometric probe
is sufficiently similar to one or more biometric references (37.03.16)
Note 1 to entry: Output of the biometric candidate list or the comparison decision implies implementation of a
policy.
Note 2 to entry: The biometric reference database need not contain biometric data (37.03.06) from multiple
biometric data subjects (37.07.05).
37.05.07
comparison
DEPRECATED match
DEPRECATED matching
estimation, calculation or measurement of similarity or dissimilarity between a biometric probe(s)
(37.03.14) and a biometric reference(s) (37.03.16)
37.05.08
enrol
create and store a biometric enrolment data record (37.03.10) in accordance with the biometric enrolment
(37.05.03) policy
© ISO/IEC 2022 – All rights reserved

37.05.09
intermediate biometric sample processing
any manipulation of a biometric sample (37.03.21) that does not produce biometric features (37.03.11)
EXAMPLE Cropping, down-sampling, compression, conversion to data interchange formats standard and
image enhancement.
Note 1 to entry: Intermediate biometric sample (37.03.30) processing changes the representation of the signal or
data.
37.05.10
one-to-one comparison
process in which a biometric probe(s) (37.03.14) from one biometric data subject (37.07.05) is compared
to a biometric reference(s) (37.03.16) from one biometric data subject to produce a comparison score
(37.03.27).
Note 1 to entry: In the case of a multimodal (37.02.06) biometric system (37.02.03), the biometric probe and the
biometric reference can contain multiple biometric modes (37.02.05).
Note 2 to entry: Some one-to-one comparison algorithms, i.e. those using score normalization, cohort models
or likelihood-ratios, can require comparisons (37.05.07) of the biometric probe from one biometric data subject
to biometric references from multiple biometric data subjects. Nevertheless, the comparison score generated
refers to the similarity between biometric probe(s) of one biometric data subje
...