Pitch Tracking
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Presentation Transcript
MUMT 611 Philippe Zaborowski February 2005 Pitch Tracking
Pitch Tracking • Goal is to track the fundamental • Vast area of research mostly focused on voice coding • Dozens of different algorithms • All algorithms have limitations • None are ideal
Algorithm Classification • Time Domain • Spectral Domain • Combined Time/Spectral Domain • Neural Networks
Time Domain • Common Features: • Analysis performed on sample basis instead of buffered intervals • No transformation needed • Cheap on computation • Common Drawbacks: • Not suited for signals where the fundamental is weak and the harmonics are strong • DC offset can be a problem
Time Domain • Threshold Crossing (zero crossing)
Time Domain • Dolansky (1954)
Time Domain • Rabiner and Gold (1969)
Time Domain • Autocorrelation (Rabiner 1977)
Time Domain • Average Magnitude Difference Function (Ross 1974)
Time Domain • Cooper and Ng (1994)
Time/Spectral Domain • Least-Square (Choi 1995) • Combines the reliability of frequency-domain with high resolution of time-domain • Able to analyze shorter signal segments • Suitable for real-time • Uses constant Q tranform
Spectral Domain • Common Features: • Transformation from time to spectral domain is computationally intensive • Superior control and analysis of formants • Common Drawbacks: • Simple study of spectrum not enough • DFT based algorithms use equally spaced bins
Spectral Domain • FFT with different harmonic analysis: • Maximum of FFT (Division Method) • Piszczalski and Galler (1979) • Harmonic Product (Schroeder 1968)
Spectral Domain • Constant Q transform (Brown and Puckette 1992)
Spectral Domain • Cepstrum (Andrews 1990)
Conclusion • Spectral Domain: • Give good results • Require a demanding analysis of spectrum • Time Domain: • Generally inferior to spectral domain • Some have comparable results with less computation