Subject: [Speechsc] definition of speaker identification

From: "Judith Markowitz" <[email-masked]>
Date: Tue, 22 May 2007 13:20:42 -0500

Dan

I apologize for not referencing your email of May 9 (below) which extends
the core definitions of speaker identification and verification to the MRCP
implementation. Your proposed changes do contain the modifications I was
seeking. 

Thank you

Judith 

From: Daniel C. Burnett [[email-masked]]
Sent: Wednesday, May 09, 2007 2:30 PM
To: [email-masked]; [email-masked]
Subject: RE: [Speechsc] proposed change to definition of "speaker
identification"

Attachments: ATT00194.txt

Judith,

Thank you for your suggestion.  You are right that the current definition in
MRCPv2 draft 12 of speaker identification is incorrect.  I'd like to give a
bit of history before I propose a modification of your suggestion.

When we first introduced speaker authentication (verification and
identification) features into MRCP, the definition of speaker identification
was close, if not identical, to the one you provide below.  Identification
was clearly described as a no-claim process.

During work on the specification, it became clear that some technology
vendors provided, instead of identification per se, an ability to perform
verification, individually, against multiple voiceprints, where a
verification result was returned for each voiceprint.  This is, of course,
merely an convenience loop placed around single-voiceprint verification.
Further, they allowed this to be done by giving a single "voiceprint group
identifier" to represent this group of voiceprints.  Notice that in both of
these cases results may be returned for multiple voiceprints.

Those of us participating in the development of MRCPv2 decided that it was
possible to combine the three notions (verification against a single
voiceprint, identification, and verification individually against multiple
voiceprints) into a single API.  That API is the one we have today.

I think we should incorporate your explanations that provide proper,
industry-accepted terminology.

Since it is also important to provide an explanation that assists in
understanding the API, in addition I think we should state more clearly that
we have taken these separate processes and combined them within our API.

Here is my counter-proposal.  Replace the following:

=========

Speaker identification identifies the speaker among a set of users by

   matching against a set of voiceprints.  (This function is also called

   Multi-Verification).  Speaker identification can be performed on a

   small set of users or for a large population.  This capability is

   useful for applications where multiple users share the same access

   privileges to some data or application, but where the individual

   speaker must be uniquely identified from the group.  It is also

   useful for real time or post processing of recorded content to

   ascertain who was speaking when.  Speaker identification is also done

   in two phases, a designation phase and an execution phase.

=========

with

=========

Speaker identification is the process of associating an unknown speaker with
a member in a population. It does not employ a claim of identity.

When an individual claims to belong to a group (e.g., one of the owners of a
joint bank account) a group authentication is performed. This is generally
implemented as a kind of verification involving comparison with more than
one voice model. It is sometimes called 'multi-verification.'  If the
individual speaker can be identified from the group, this may be useful for
applications where multiple users share the same access privileges to some
data or application.

Speaker identification and group authentication are also done in two phases,
a designation phase and an execution phase.

Note that from a functionality standpoint identification can be thought of
as a special case of group authentication (if the individual is identified)
where the group is the entire population, although the implementation of
speaker identification may be different from the way group authentication is
performed.

To accommodate single-voiceprint verification, verification against multiple
voiceprints, group authentication, and identification, this specification
provides a single set of methods that can take a list of identifiers, called
"voiceprint identifiers", and return a list of identifiers, with a score for
each representing how well the input speech matched each identifier.  The
input and output lists of identifiers do not have to match, allowing a
vendor-specific group identifier to be used as input to indicate that
identification is to be performed.

In this specification, the terms "Identification" and "Multi-verification"
are used to indicate that the input represents a group (potentially the
entire population)  and that results for multiple voiceprints may be
returned.

=========

What do you think?

-- dan

  _____  

From: Judith Markowitz [mailto:[email-masked]] 
Sent: Wednesday, May 02, 2007 5:15 PM
To: [email-masked]
Subject: [Speechsc] proposed change to definition of "speaker
identification"

The definition of "speaker identification" is incorrect because it portrays
speaker as a kind of verification. In fact, it is entirely different. It is
important that the speech-processing industry be in step with both the
research community and the biometrics industry. The recommended change is an
editorial one and does not affect the specification in any way other than to
provide a proper definition. 

Here is the proposed change:

"Speaker identification is the process of associating an unknown speaker
with a member in a population. It does not employ a claim of identity.
Speaker verification is the process of verifying whether an unknown speaker
is the person as claimed. It is a yes/no process performed in response to a
claim of identity."

If the committee wants to include the concept of making a claim of
membership (which is now erroneously included as a kind of speaker
identification) you can add

"When an individual claims to belong to a group (e.g., one of the owners of
a joint bank account) a group authentication is performed. This is generally
implemented as a kind of verification involving comparison with more than
one voice model. It is sometimes called 'multi-verification.'"

Thank you for your kind attention to this request. 

Judith Markowitz

Co-chair Speaker Biometrics Committee, VoiceXML Forum 

Invited Expert in Speaker Recognition to the W3C Voice Browser Working Group

VoiceXML Forum liaison to ANSI/INCITS/Mi(biometrics) 

Editor, ANSI/INCITS data exchange format project for speaker biometrics

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