Voice Biometrics: How does it work? Konstantin Simonchik

Transcription

1 Voic Biomtrics: How dos it work? Konstantin Simonchik Lappnranta, 4 Octobr 2012

2 Voicprint Makup Fingrprint Facprint Lik a ingrprint or acprint, a voicprint also has availabl paramtrs that provid uniqu inormation about a prson. Ths paramtrs ar individual to ach prson, and can provid vry usul inormation about th prson s idntity. Voicprint 2

3 Spakr Rcognition Tasks Idntiication Whos voic is this? Vriication Is this Bob s voic? Closd or Opn St Conditions Txt indpndnt mod Convrsational styl Tlphon/microphon channl Languag indpndnt 3

4 Ky Challngs o Voic Channl cts Microphons (carbon-button, lctrt, hands-r ) Acoustic Environmnt (oic, car, airport ) Transmission Channl (landlin, cllular, VoIP ) Spakr voic variability Emotional stat Physical condition (drugs, alcohol ) Illnss Amount o spch Elimination o pauss and non-spch sgmnts Non-Challngs Languag Accnts Supricial voic disguis 4

5 Spakr Rcognition Systm 1-1 Voic Modls 1, 2,,N N Spch Spakr #2 Spakr Rcognition Systm «Accpt» or «Rjct» Accpt 5

6 Spakr Rcognition Systm 1-N Voic Modls 1, 2,,N N Spch Spakr Rcognition Systm «Spakr ID» or «No Match» Spakr #2 6

7 Prormanc Masurs FRR/FAR Plot EER Thrshold FRR - Fals Rjction Rat FAR - Fals Accptanc Rat EER - Equal Error Rat DCF - Dtction Cost Function Exampl: DCF = FRR FAR (NIST SRE 2010) 7

8 Pitch Basd Mthod Pitch (or Fundamntal Frquncy) - th rlativ highnss or lownss o a ton as prcivd by th ar, which dpnds on th numbr o vibrations pr scond producd by th vocal cords. 170 Hz 110 Hz An xampl o automatd pitch xtraction in th phras Fornsic audio pronouncd by two dirnt prsons is shown in th pictur 8

9 Simpl Pitch Basd SR Systm Pitch xtraction Etalon E N Pitch statistics stimation Comparison o Etalon and Tst statistics s1 s2 S... s N Distanc N i1 - Pitch mdian - Pitch man - Pitch min - tc wight i ( s i ) i 2 Etalons Databas Dcision: Accpt/Rjct 9

10 Spctral-ormant Mthod Formants - acoustic rsonancs o th human vocal tract Spctral-ormant mthod (SFM) is basd on th uniqu shap o ach prson s vocal tract which is rlctd in th visibl spch o dirnt popl. An xampl o ormant rprsntation o th phras Fornsic audio pronouncd by two dirnt prsons is shown in th pictur (Th horizontal axis is tim in sconds. Th vrtical axis is rquncy in Hrtz. Enrgy lvl is dpictd by th darknss o th trac). 10

11 11 Simpl Formant Basd SR Systm Formants statistics stimation Comparison o Etalon and Tst statistics Dcision: Accpt/Rjct Formants xtraction Etalons Databas M M M M E Etalon N N N N F N i i j i T i j i W Distanc 1 ) ( ) ( ) ( ) (

12 GMM Basd Mthods In th GMM approach Gaussian mixturs ar usd to approximat statistical distributions o spch charactristics paramtrs. Fatur xtraction - MFCC / LFCC / PLP / tc GMM stimation - MAP adaptation S M Channl compnsation - Joint Factor Analysis - LDA / PLDA C Classiication Dcision: Accpt/Rjct - SVM - ANN 12

13 Fusion o SR Mthods Fusion schma Spakr Idntiication Systm Mthod #1 Spch Mthod #2 Fusion Dcision Mthod #3 Pitch basd mthod EER= 15% Spctral-ormant mthod Fusion EER= 10% EER= 2% GMM basd mthod EER= 3% 13

14 NIST Spakr Rcognition Evaluation NIST SRE is a world s lading valuation in th ild o txt indpndnt spakr rcognition. Evry two yars it gathrs lading rsarchrs, univrsitis and companis rom all ovr th world. Th main objctiv o th valuations is to driv th tchnology orward, to masur th stat-o-th-art, and to ind th most promising algorithmic approachs. - Spch databass providd by LDC - Mtric: DCF = FR FA 14

15 NIST SRE 2010 Participation 15

16 NIST SRE 2010 Participation 16

17 ABOUT COMPANY Spch Tchnology Cntr Spch Tchnology Cntr (STC) is an intrnational ladr in spch tchnology and multimodal biomtrics. It has ovr 20 yars o rsarch, dvlopmnt and implmntation xprinc in Russia and intrnationally. STC is lading global providr o innovativ systms in high-quality rcording, audio and vido procssing and analysis, nois cancllation, spch synthsis and rcognition, and ral-tim, high-accuracy voic and acial biomtrics solutions. STC innovations ar usd in both public and commrcial sctors, rom small xprt laboratoris, to larg, distributd contact cntrs, to nation-wid scurity systms. CONTACTS Russia 4 Krasutskogo strt, St. Ptrsburg, Tl.: Fax: stc-spb@spchpro.com STC is ISO-9001: 2008 crtiid. STC is opn to commrcial and R&D coopration! 17

18 Спасибо за внимание! Thank you or your attntion! 18