Progress in Nonlinear Speech Processing pp 41-57

Part of the Lecture Notes in Computer Science book series (LNCS, volume 4391) | Cite as

Spectral Analysis of Speech Signals Using Chirp Group Delay

  • Baris Bozkurt
  • Thierry Dutoit
  • Laurent Couvreur

Abstract

This study presents chirp group delay processing techniques for spectral analysis of speech signals. It is known that group delay processing is potentially very useful for spectral analysis of speech signals. However, it is also well known that group delay processing is difficult due to large spikes that mask the formant structure. In this chapter, we first discuss the sources of spikes on group delay functions, namely the zeros closely located to the unit circle. We then propose processing of chirp group delay functions, i.e. group delay functions computed on a circle other than the unit circle in z-plane. Chirp group delay functions can be guaranteed to be spike-free if zero locations can be controlled. The technique we use here for that is to compute the zero-phased version of the signal for which the zeros appear very close (or on) the unit circle. The final representation obtained is named as the chirp group delay of zero-phased version of a signal (CGDZP). We demonstrate use of CGDZP in two applications: formant tracking and feature extraction for automatic speech recognition (ASR). We show that high quality formant tracking can be performed by simply picking peaks on CGDZP and CGDZP is potentially useful for improving ASR performance.

Keywords

Phase processing chirp group delay group delay zzt ASR feature extraction 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Yegnanarayana, B., Duncan, G., Murthy, H.A.: Improving formant extraction from speech using minimum-phase group delay spectra. In: Proc. of European Signal Processing Conference (EUSIPCO), Grenoble, France, Sep. 5-8, 1988, pp. 447–450 (1988)Google Scholar
  2. 2.
    Murthy, H.A., Murthy, K.V., Yegnanarayana, B.: Formant extraction from phase using weighted group delay function. Electronics Letters 25(23), 1609–1611 (1989)CrossRefGoogle Scholar
  3. 3.
    Murthy, H.A., Yegnanarayana, B.: Formant extraction from group delay function. Speech Communication 10(3), 209–221 (1991)CrossRefGoogle Scholar
  4. 4.
    Bozkurt, B., Doval, B., D’Alessandro, C., Dutoit, T.: Appropriate windowing for group delay analysis and roots of z-transform of speech signals. In: Proc. of European Signal Processing Conference (EUSIPCO), Vienna, Austria, Sep. 6–10 (2004)Google Scholar
  5. 5.
    Oppenheim, A.V., Schafer, R.W., Buck, J.R.: Discrete-Time Signal Processing, 2nd edn. Prentice-Hall, Englewood Cliffs (1999)Google Scholar
  6. 6.
    Yegnanarayana, B., Saikia, D.K., Krishnan, T.R.: Significance of group delay functions in signal reconstruction from spectral magnitude or phase. IEEE Trans. on Acoustics, Speech and Signal Processing 32(3), 610–623 (1984)CrossRefGoogle Scholar
  7. 7.
    Hegde, R.M., Murthy, H.A., Gadde, V.R.: The modified group delay feature: A new spectral representation of speech. In: Proc. of International Conference on Spoken Language Processing (ICSLP), Jeju Island, Korea, Oct. 4-8 (2004)Google Scholar
  8. 8.
    Bozkurt, B.: New spectral methods for analysis of source/filter characteristics of speech signals. PhD Thesis, Faculté Polytechnique De Mons, Presses universitaires de Louvain (2006)Google Scholar
  9. 9.
    Fant, G.: The LF-model revisited. Transformation and frequency domain analysis. Speech Trans. Lab. Q. Rep., Royal Inst. of Tech. Stockholm 2-3, 121–156 (1995)Google Scholar
  10. 10.
    Demo Page for Zeros of the Z-Transform (ZZT) Representation: http://tcts.fpms.ac.be/demos/zzt
  11. 11.
    Zhu, D., Paliwal, K.K.: Product of power spectrum and group delay function for speech recognition. In: Proc. of International Conference on Acoustics, Speech and Signal Processing (ICASSP), Montreal, Canada, May 17–21, 2004, pp. 125–128 (2004)Google Scholar
  12. 12.
    Rabiner, L.R., Schafer, R.W., Rader, C.M.: The chirp z-transform algorithm and its application. Bell System Tech. J. 48(5), 1249–1292 (1969)MathSciNetGoogle Scholar
  13. 13.
    Hirsch, H.G., Pearce, D.: The AURORA experimental framework for the performance evaluation of speech recognition Systems under noisy conditions. In: Proc. of ASR 2000, Paris, France, Sep. 18–20 (2000)Google Scholar
  14. 14.
  15. 15.
  16. 16.
  17. 17.
    Hegde, R.M., Murthy, H.A., Gadde, V.R.: Continuous speech recognition using joint features derived from the modified group delay function and MFCC. In: Proc. of International Conference on Spoken Language Processing (ICSLP), Jeju Island, Korea, Oct. 4-8 (2004)Google Scholar
  18. 18.
    Boite, J.-M., Couvreur, L., Dupont, S., Ris, C.: Speech Training and Recognition Unified Tool (STRUT), http://tcts.fpms.ac.be/asr/project/strut
  19. 19.
    Bourlard, H., Morgan, N.: Connectionist Speech Recognition: A Hybrid Approach. Kluwer Academic Publishers, Dordrecht (1994)Google Scholar
  20. 20.
    Gong, Y.: Speech recognition in noisy environments: a survey. Speech Communication 16(3), 261–291 (1995)CrossRefGoogle Scholar
  21. 21.
    Junqua, J.C.: Robust Speech Processing in Embedded Systems and PC Applications. Kluwer Academic Publishers, Dordrecht (2000)Google Scholar
  22. 22.
    Bozkurt, B., Dutoit, T.: Mixed-phase speech modeling and formant estimation, using differential phase spectrums. In: Proc. of ISCA ITRW VOQUAL, Aug. 2003, pp. 21–24 (2003)Google Scholar
  23. 23.
    Introduction page for Chirp Group Delay processing: http://tcts.fpms.ac.be/demos/zzt/cgd.html
  24. 24.
    Bozkurt, B., Doval, B., d’Alessandro, C., Dutoit, T.: Zeros of z-transform representation with application to source-filter separation in speech. IEEE Signal Processing Letters 12(4), 344–347 (2005)CrossRefGoogle Scholar
  25. 25.
    Fant, G.: Acoustic Theory of Speech Production. Mouton and Co., The Hague (1960)Google Scholar

Copyright information

© Springer Berlin Heidelberg 2007

Authors and Affiliations

  • Baris Bozkurt
    • 1
  • Thierry Dutoit
    • 1
  • Laurent Couvreur
    • 1
  1. 1.TCTS Lab., Faculté Polytechnique De Mons, Initialis Scientific Parc, B-7000, MonsBelgium

Personalised recommendations