Forensic Speaker Identification

360 Pages·1996·4.972 MB·English

by  Tom Warlow, T A Warlow

Forensic Speaker
Identification
i
© 2002 Taylor & Francis
Taylor & Francis Forensic Science Series
Edited by James Robertson
Forensic Sciences Division, Australian Federal Police
Firearms, the Law and Forensic Ballistics
T A Warlow
ISBN 0 7484 0432 5
1996
Scientific Examination of Documents: methods and techniques, 2nd edition
D Ellen
ISBN 0 7484 0580 1
1997
Forensic Investigation of Explosions
A Beveridge
ISBN 0 7484 0565 8
1998
Forensic Examination of Human Hair
J Robertson
ISBN 0 7484 0567 4
1999
Forensic Examination of Fibres, 2nd edition
J Robertson and M Grieve
ISBN 0 7484 0816 9
1999
Forensic Examination of Glass and Paint: analysis and interpretation
B Caddy
ISBN 0 7484 0579 9
2001
ii
© 2002 Taylor & Francis
Forensic Speaker
Identification
Philip Rose
London and New York
iii
© 2002 Taylor & Francis
First published 2002 by Taylor & Francis
11 New Fetter Lane, London EC4P 4EE
Simultaneously published in the USA and Canada
by Taylor & Francis Inc,
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Taylor & Francis is an imprint of the Taylor & Francis Group
© 2002 Taylor & Francis
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Printed and bound in Great Britain by TJ International Ltd, Padstow, Cornwall
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ISBN 0-415-27182-7
iv
© 2002 Taylor & Francis
To my mum, who died on the day before she could see this book
finished.
To my dad, who taught me how to observe.
v
© 2002 Taylor & Francis
Contents
Acknowledgements
1 Introduction
Forensic speaker identification
Forensic phonetics
Readership
The take-home messages
Argument and structure of the book
2 Why voices are difficult to discriminate forensically
Between-speaker and within-speaker variation
Probabilities of evidence
Distribution in speaker space
Multidimensionality
Discrimination in forensic speaker identification
Dimensional resolving power
Ideal vs. realistic conditions
Lack of control over variation
Reduction in dimensionality
Representativeness of forensic data
Legitimate pooling of unknown samples
Chapter summary
3 Forensic-phonetic parameters
Types of parameters
Acoustic vs. auditory parameters
Traditional vs. automatic acoustic parameters
Linguistic vs. non-linguistic parameters
Linguistic sources of individual variation
Forensic significance: linguistic analysis
Quantitative and qualitative parameters
Discrete and continuous parameters
Requirements on forensic-phonetic parameters
Chapter summary
© 2002 Taylor & Francis
4 Expressing the outcome
The likelihood ratio
Combination of likelihood ratios
Prior odds
Alternative hypothesis
Bayesian inference
Pros and cons
Pro-Bayesian arguments
Anti-Bayesian arguments
A reality check
Chapter summary
5 Characterising forensic speaker identification
Speaker recognition
Speaker identification and verification
Relationship between forensic speaker identification and
speaker identification/verification
Summary: Verification and identification
Naive and technical speaker recognition
Technical speaker recognition
Conditions on forensic-phonetic speaker identification experiments
Naive speaker recognition
Naive speaker recognition: Discussion
Familiarisation in auditory forensic analysis
Aural-spectrographic (voiceprint) identification
Linguistic controversy
Legal controversy
Summary: Aural-spectrographic method
Chapter summary
6 The human vocal tract and the production and description
of speech sounds
The vocal tract
The basic dichotomy
Vocal cords
Forensic significance: Vocal cord activity
Summary: Vocal cord activity
The supralaryngeal vocal tract
Forensic significance: Nasals and nasalisation
Squeezing the supralaryngeal vocal tract tube: Vowels and consonants
Place and manner description of consonants
Place of articulation
English consonants
Vowels
Primary parameters of vowel description
Secondary parameters of vowel description
English vowels
The componentiality of speech sounds
© 2002 Taylor & Francis