Non-contemporaneous speech samples from 27 male speakers of Australian English were compared in a forensic likelihood-ratio framework. Parametric curves (polynomials and discrete cosine transforms) were fitted to the formant trajectories of the diphthongs ∕aɪ∕, ∕eɪ∕, ∕oʊ∕, ∕aʊ∕, and ∕ɔɪ∕. The estimated coefficient values from the parametric curves were used as input to a generative multivariate-kernel-density formula for calculating likelihood ratios expressing the probability of obtaining the observed difference between two speech samples under the hypothesis that the samples were produced by the same speaker versus under the hypothesis that they were produced by different speakers. Cross-validated likelihood-ratio results from systems based on different parametric curves were calibrated and evaluated using the log-likelihood-ratio cost function . The cross-validated likelihood ratios from the best-performing system for each vowel phoneme were fused using logistic regression. The resulting fused system had a very low error rate, thus meeting one of the requirements for admissibility in court.
REFERENCES
1.
Aitken
, C. G. G.
, and Lucy
, D.
(2004
). “Evaluation of trace evidence in the form of multivariate data
,” Appl. Stat.
54
, 109
–122
.2.
Aitken
, C. G. G.
, and Stoney
, D. A.
(1991
). The Use of Statistics in Forensic Science
(Horwood
, Chichester, UK
).3.
Aitken
, C. G. G.
, and Taroni
, F.
(2004
). Statistics and the Evaluation of Evidence for Forensic Scientists
(Wiley
, Chichester, UK
).4.
Balding
, D. J.
(2005
). Weight of Evidence for Forensic DNA Profiles
(Wiley
, Chichester, UK
).5.
Boersma
, P.
(1993
). “Accurate short-term analysis of the fundamental frequency and the harmonics-to-noise ratio of a sampled sound
,” Proceedings of the Institute of Phonetic Sciences
(Institute of Phonetic Sciences
, Amsterdam
), Vol. 17
, pp. 97
–110
.6.
Broeders
, A. P. A.
(1999
). “Some observations on the use of probability scales in forensic identification
,” Forensic Ling.
6
, 1350
–1771
.7.
Broeders
, A. P. A.
(2004
). “Forensic speech and audio analysis forensic linguistics: A review 2001 to 2004
,” in 14th International Forensic Science Symposium Review Papers
, edited by N.
Nic Daéid
(Interpol
, Lyon, France
), pp. 170
–188
.8.
Brümmer
, N.
, Burget
, L.
, Cernocký
, J. H.
, Glembek
, O.
, Grézl
, F.
, Karafiát
, M.
, van Leeuwen
, D. A.
, Matejka
, P.
, Schwarz
, P.
, and Strasheim
, A.
(2007
). “Fusion of heterogenous speaker recognition systems in the STBU submission for the NIST SRE 2006
,” IEEE Trans. Audio, Speech, Lang. Process.
15
, 2072
–2084
.9.
Brümmer
, N.
, and du Preez
, J.
(2006
). “Application independent evaluation of speaker detection
,” Comput. Speech Lang.
20
, 230
–275
.10.
Cox
, F.
, and Palethorpe
, S.
(2007
). “Australian English
,” J. Int. Phonetic Assoc.
37
, 341
–350
.11.
Eriksson
, E. J.
, Cepeda
, L. F.
, Rodman
, R. D.
, McAllister
, D. F.
, Bitzer
, D.
, and Arroway
, P.
(2004
). “Cross-language speaker identification using spectral moments
,” in Proceedings of FONETIK 2004: The XVIIth Swedish Phonetics Conference
, edited by P.
Branderud
and H.
Traunmüller
(Department of Linguistics
, Stockholm University, Sweden
), pp. 76
–79
.12.
Eriksson
, E. J.
, Cepeda
, L. F.
, Rodman
, R. D.
, Sullivan
, K. P. H.
, McAllister
, D. F.
, Bitzer
, D.
, and Arroway
, P.
(2004
). “Robustness of spectral moments: A study using voice imitations
,” in Proceedings of the Tenth Australian International Conference on Speech Sciences and Technology
, edited by S.
Cassidy
, F.
Cox
, R.
Mannell
, and S.
Palethorpe
(Australian Speech Science and Technology Association
, Canberra, Australia
), pp. 259
–264
.13.
Evett
, I. W.
(1998
). “Towards a uniform framework for reporting opinions in forensic science casework
,” Sci. Justice
38
, 198
–202
.14.
Friedman
, R. D.
(1996
). “Assessing evidence
,” Mich. Law Rev.
94
, 1810
–1838
.15.
Goldstein
, U. G.
(1976
). “Speaker-identifying features based on formant tracks
,” J. Acoust. Soc. Am.
59
, 176
–182
.16.
González-Rodríguez
, J.
, Drygajlo
, A.
, Ramos
, D.
, García-Gomar
, M.
, and Ortega-García
, J.
(2006
). “Robust estimation, interpretation and assessment of likelihood ratios in forensic speaker recognition
,” Comput. Speech Lang.
20
, 331
–355
17.
González-Rodríguez
, J.
, Rose
, P.
, Ramos
, D.
, Toledano
, D. T.
, and Ortega-García
, J.
(2007
). “Emulating DNA: Rigorous quantification of evidential weight in transparent and testable forensic speaker recognition
,” IEEE Trans. Audio, Speech, Lang. Process.
15
, 2104
–2115
.18.
Gottfried
, M.
, Miller
, J. D.
, and Meyer
, D. J.
(1993
). “Three approaches to the classification of American English diphthongs
,” J. Phonetics
21
, 205
–229
.19.
Greisbach
, R.
, Esser
, O.
, and Weinstock
, C.
(1995
). “Speaker identification by formant contours
,” in Studies in Forensic Phonetics
, edited by A.
Braun
and J.-P.
Köster
(Wissenschaftlicher
, Trier, Germany
), pp. 49
–55
.20.
Hillenbrand
, J. M.
, Clark
, M. J.
, and Nearey
, T. N.
(2001
). “Effect of consonant environment on vowel formant patterns
,” J. Acoust. Soc. Am.
109
, 748
–763
.21.
22.
Ingram
, J. C. L.
, Prandolini
, R.
, and Ong
, S.
(1996
). “Formant trajectories as indices of speaker identification
,” Forensic Ling. The Int. J. of Speech Lang. and the Law
3
, 129
–145
.23.
Ishihara
, S.
, and Kinoshita
, Y.
(2008
). “How many do we need? Exploration of the population size effect on the performance of forensic speaker classification
,” Proceedings of Interspeech 2008 Incorporating SST 2008
, International Speech Communication Association, pp. 1941
–1944
.24.
Jessen
, M.
(2008
). “Forensic phonetics
,” Lang. and Ling. Compass
2
, 671
–711
.25.
Kasuya
, H.
, Tan
, X.
, and Yang
, C.-S.
(1994
). “Voice source and vocal tract characteristics associated with speaker individuality
,” Proceedings of the Third International Conference on Spoken-Language Processing, Yokohama
, pp. 1459
–1462
.26.
Kinoshita
, Y.
, and Osanai
, T.
(2006
). “Within speaker variation in diphthongal dynamics: What can we compare
?” in Proceedings of the 11th Australasian International Conference on Speech Science and Technology, Auckland, New Zealand
, edited by P.
Warren
and C. I.
Watson
(Australasian Speech Science and Technology Association
, Canberra, Australia
), pp. 112
–117
.27.
Lucy
, D.
(2005
). Introduction to Statistics for Forensic Scientists
(Wiley
, Chichester, UK
).28.
Markel
, J. D.
, and Gray
, A. H.
(1976
). Linear Prediction of Speech
(Springer-Verlag
, Berlin
).29.
McDougall
, K.
(2004
). “Speaker-specific formant dynamics: An experiment on Australian English ∕aɪ∕
,” Int. J. of Speech, Lang. and the Law
11
, 103
–130
.30.
McDougall
, K.
(2006
). “Dynamic features of speech and the characterization of speakers
,” Int. J. of Speech, Lang. and the Law
13
, 89
–126
.31.
McDougall
, K.
, and Nolan
, F.
(2007
). “Discrimination of speakers using the formant dynamics of ∕u∕ in British English
,” in Proceedings of the 16th International Congress on Phonetic Sciences, Saarbrücken
, edited by J.
Trouvain
and W. J.
Barry
(Universität des Saarlandes
, Saarbrücken, Germany
), pp. 1825
–1828
.32.
Menard
, S.
(2002
). Applied Logistic Regression Analysis
, 2nd ed. (Sage
, Thousand Oaks, CA
).33.
Morrison
, G. S.
(2008
). “Forensic voice comparison using likelihood ratios based on polynomial curves fitted to the formant trajectories of Australian English ∕aɪ∕
,” Int. J. of Speech, Lang. and the Law
15
, pp. 247
–264
.34.
Morrison
, G. S.
, and Kinoshita
, Y.
(2008
). “Automatic-type calibration of traditionally derived likelihood ratios: Forensic analysis of Australian English ∕o∕ formant trajectories
,” Proceedings of Interspeech 2008 Incorporating SST 2008
, International Speech Communication Association
, pp. 1501
–1504
.35.
Nearey
, T. M.
, and Assmann
, P. F.
(1986
). “Modeling the role of vowel inherent spectral change in vowel identification
,” J. Acoust. Soc. Am.
80
, 1297
–1308
.36.
Nearey
, T. M.
, Assmann
, P. F.
, and Hillenbrand
, J. M.
(2002
). “Evaluation of a strategy for automatic formant tracking
,” J. Acoust. Soc. Am.
112
, 2323
.37.
Nolan
, F.
(1997
). “Speaker recognition and forensic phonetics
,” in The Handbook of Phonetic Sciences
, edited by W. J.
Hardcastle
and J.
Laver
(Blackwell
, Oxford
), pp. 744
–767
.38.
Nolan
, F.
, and Grigoras
, C.
(2005
). “A case for formant analysis in forensic speaker identification
,” Int. J. of Speech, Lang. and the Law
12
, 144
–173
.39.
Pigeon
, S.
, Druyts
, P.
, and Verlinde
, P.
(2000
). “Applying logistic regression to the fusion of the NIST’99 1-speaker submissions
,” Digit. Signal Process.
10
, 237
–248
.40.
Ramos Castro
, D.
(2007
). “Forensic evaluation of the evidence using automatic speaker recognition systems
,” Ph.D. dissertation, Universidad Autónoma de Madrid
, Madrid, Spain.41.
Rodman
, R.
, McAllister
, D.
, Bitzer
, D.
, Cepeda
, L.
, and Abbitt
, P.
(2002
). “Forensic speaker identification based on spectral moments
,” Int. J. of Speech, Lang. and the Law
9
, 22
–43
.42.
Rose
, P.
(2002
). Forensic Speaker Identification
(Taylor & Francis
, London
).43.
Rose
, P.
(2003
). Expert Evidence, Issue 99: The Technical Comparison of Forensic Voice Samples
(Thomson Lawbook
, Sydney, Australia
).44.
Rose
, P.
(2005
). “Forensic speaker recognition at the beginning of the twenty-first century: An overview and a demonstration
,” Aus. J. of Forensic Sci.
37
, 49
–72
.45.
Rose
, P.
(2006a
). “Accounting for correlation in linguistic-acoustic likelihood ratio-based forensic speaker discrimination
,” in Speaker and Language Recognition Workshop, 2006. IEEE Odyssey 2006
, edited by K.
Berkling
and P. A.
Torres-Carrasquillo
, pp. 1
–8
.46.
Rose
, P.
(2006b
). “Technical forensic speaker recognition: Evaluation, types and testing of evidence
,” Comput. Speech Lang.
20
, 159
–191
.47.
Rose
, P.
(2006c
). “The intrinsic forensic discriminatory power of diphthongs
,” in Proceedings of the 11th Australasian International Conference on Speech Science and Technology, Auckland, New Zealand
, edited by P.
Warren
and C. I.
Watson
(Australasian Speech Science and Technology Association
, Canberra, Australia
), pp. 64
–69
.48.
Rose
, P.
(2007
). “Forensic speaker discrimination with Australian English vowel acoustics
,” in Proceedings of the 16th International Congress on Phonetic Sciences, Saarbrücken
, edited by J.
Trouvain
and W. J.
Barry
(Universität des Saarlandes
, Saarbrücken, Germany
), pp. 1817
–1820
.49.
Rose
, P.
, Kinoshita
, Y.
, and Alderman
, T.
(2006
). “Realistic extrinsic forensic speaker discrimination with the diphthong ∕aɪ∕
,” in Proceedings of the 11th Australasian International Conference on Speech Science and Technology, Auckland, New Zealand
, edited by P.
Warren
and C. I.
Watson
(Australasian Speech Science and Technology Association
, Canberra, Australia
), pp. 329
–334
.50.
Rose
, P.
, Kinoshita
, Y.
, and Ishihara
, S.
(2008
). “Beyond the long-term mean: Exploring the potential of F0 distribution parameters in traditional forensic speaker recognition
,” Proceedings of the Odyssey Speaker and Language Recognition Workshop 2008
, Stellenbosch, South Africa
, pp. 329
–334
.51.
van Leeuwen
, D. A.
, and Brümmer
, N.
(2007
). “An introduction to application-independent evaluation of speaker recognition systems
,” in Speaker Classification I: Selected Projects
, edited by C.
Müller
(Springer
, Heidelberg, Germany
), pp. 330
–353
.52.
Watson
, C. I.
, and Harrington
, J.
(1999
). “Acoustic evidence of dynamic formant trajectories in Australian English vowels
,” J. Acoust. Soc. Am.
106
, 458
–468
.53.
Zahorian
, S. A.
, and Jagharghi
, A. J.
(1991
). “Speaker normalization of static and dynamic vowel spectral features
,” J. Acoust. Soc. Am.
90
, 67
–75
.54.
Zahorian
, S. A.
, and Jagharghi
, A.
(1993
). “Spectral-shape features versus formants as acoustic correlates for vowels
,” J. Acoust. Soc. Am.
94
, 1966
–1982
.55.
Zhang
, C.
, Morrison
, G. S.
, and Rose
, P.
(2008
). “Forensic speaker recognition in Chinese: A multivariate likelihood ratio discrimination on ∕ɪ∕ and ∕y∕
,” Proceedings of Interspeech 2008 Incorporating SST 2008
, International Speech Communication Association
, pp. 1937
–1940
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