The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

Model-Based Analysis of Noisy Musical Recordings with Application to Audio Restoration

Paulo A. A. Esquef

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 2nd of April, 2004, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-6950-3)   [240 KB]
Dissertation is also available in print (ISBN 951-22-6945-7)


This thesis proposes digital signal processing algorithms for noise reduction and enhancement of audio signals. Approximately half of the work concerns signal modeling techniques for suppression of localized disturbances in audio signals, such as impulsive noise and low-frequency pulses. In this regard, novel algorithms and modifications to previous propositions are introduced with the aim of achieving a better balance between computational complexity and qualitative performance, in comparison with other schemes presented in the literature. The main contributions related to this set of articles are: an efficient algorithm for suppression of low-frequency pulses in audio signals; a scheme for impulsive noise detection that uses frequency-warped linear prediction; and two methods for reconstruction of audio signals within long gaps of missing samples.

The remaining part of the work discusses applications of sound source modeling (SSM) techniques to audio restoration. It comprises application examples, such as a method for bandwidth extension of guitar tones, and discusses the challenge of model calibration based on noisy recorded sources. Regarding this matter, a frequency-selective spectral analysis technique called frequency-zooming ARMA (FZ-ARMA) modeling is proposed as an effective way to estimate the frequency and decay time of resonance modes associated with the partials of a given tone, despite the presence of corrupting noise in the observable signal.

This thesis consists of an overview and of the following 7 publications:

  1. Esquef P. A. A., Biscainho L. W. P. and Välimäki V., 2003. An efficient algorithm for the restoration of audio signals corrupted with low-frequency pulses. Journal of the Audio Engineering Society 51, number 6, pages 502-517.
  2. Esquef P. A. A., Karjalainen M. and Välimäki V., 2002. Detection of clicks in audio signals using warped linear prediction. In: Proceedings of the 14th International Conference on Digital Signal Processing (DSP2002). Santorini, Greece, 1-3 July 2002, volume 2, pages 1085-1088. © 2002 IEEE. By permission.
  3. Esquef P. A. A., Välimäki V., Roth K. and Kauppinen I., 2003. Interpolation of long gaps in audio signals using the warped Burg's method. In: Proceedings of the 6th International Conference on Digital Audio Effects (DAFx-03). London, UK, 8-11 September 2003, pages 18-23. © 2003 by authors.
  4. Esquef P. A. A., 2004. Interpolation of long gaps in audio signals using line spectrum pair polynomials. Helsinki University of Technology, Laboratory of Acoustics and Audio Signal Processing, Report 72. IEEE Transactions on Speech and Audio Processing, submitted for publication. © 2004 by author and © 2003 IEEE.
  5. Esquef P. A. A., Välimäki V. and Karjalainen M., 2002. Restoration and enhancement of solo guitar recordings based on sound source modeling. Journal of the Audio Engineering Society 50, number 4, pages 227-236.
  6. Karjalainen M., Esquef P. A. A., Antsalo P., Mäkivirta A. and Välimäki V., 2002. Frequency-zooming ARMA modeling of resonant and reverberant systems. Journal of the Audio Engineering Society 50, number 12, pages 1012-1029.
  7. Esquef P. A. A., Karjalainen M. and Välimäki V., 2003. Frequency-zooming ARMA modeling for analysis of noisy string instrument tones. EURASIP Journal on Applied Signal Processing: Special Issue on Digital Audio for Multimedia Communications 2003, number 10, pages 953-967.

Errata of publication 3

Keywords: acoustic signal processing, computer music, audio restoration, spectral analysis

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© 2004 Helsinki University of Technology

Last update 2011-05-26