Separation of Multispeaker Speech

Using Excitation InformationB.Yegnanarayana, R.Kumara Swamy and S.R.Mahadeva Prasanna

Dept of Computer Science and Engineering

Indian Institute of Technology Madras

Chennai-600036, India

yegna@cs.iitm.ernet.in

Talk at NOLISP2005

April 19, 2005

Multispeaker Speech SignalThree speaker case

) Ta) Microphone-1 signal b) Microphone-2 signal

Multispeaker Whispered SpeechThree Speaker case

Ta) Microphone-1 signal b) Microphone-2 signal

Problem

•Determine the # speakers

•Separate individual speakers

•Enhance speech of individual speakers

Organization of the talk

•Demo illustrating the problem of multispeaker separation

•Basis: Sequences of impulses in speech production

•Proposed method for speaker separation

•Discussion: Scope of the present study and key ideas

•Conclusions

Basis for the Proposed Method of Separation

•Sequences of impulses in direct speech at mic locations

•No effect of channel or other degradations on the sequence

•No two speakers are at the same location

Proposed Method for Speaker Separation

•Record multispeaker data at 2 or more mics

•Compute the HE of the LP residual

•Use peaks in crosscorrelation of HEs to obtain delays

•Take min of shifted HEs to derive HE of desired speaker

•Derive weight function and modified LP residual

•Synthesize speech for each speaker

LP analysis of Speech signal

Ta) Speech signal b) LP residual c) Hilbert Envelope of LP residual

Hilbert Envelope (HE)

Ta) HE of microphone-1 signal b) HE of microphone-2 signal

Cross-Correlation of Hilbert Envelopes

Time-delay estimation

(b) Time delay and normalized # samples

(a) Peaks in the crosscorrelation plots

Processing HE using time-delay

Ta) HE of mic-1 signal b), c) , d) Min(HE1,HE2) emphasizing

excitation information of Speaker 1,2 and 3, respectively

Results of Separation

a)LP residual of mic-1 signal b), c) and d) modified residual of sp1, sp2

Sp3 e), f) and g) Speech signals after separation

Demo of Speaker EnhancementThree speaker case

aa) Microphone-1 speech signal b) Microphone-2 speech signal

(a)

b)b)

Demo of Speaker Enhancemnt

a) Speaker 1

b) Speaker 2

c) Speaker 3

Summary

•Number of speakers (whispered), speaker separation (2 mics), speech enhancement (> 2 mics)

•Only speaker separation is addressed

•Significance of HE for delay estimation and speaker separation

Conclusions

•Need to improve the quality of enhanced speech signals

•Need more microphones for data collection

•Need to deal with moving speaker and variable # speakers

Thank you very much for your attention