A method for low-delay pitch tracking and smoothing

In this paper, a new method for pitch tracking is presented. The method is comprised of two steps. In the first step, accurate pitch estimates are obtained on a sample-by-sample basis by updates of the signal statistics with an exponential forgetting factor and subsequent numerical optimization. In the second step, a Kalman filter is used to smooth the estimates and separate the pitch into a slowly varying component and a rapidly varying component. The former represents the mean pitch while the latter represents vibrato, slides and other fast changes. The method is intended for use in applications that require fast and sample-by-sample estimates, like tuners for musical instruments, transcription tasks requiring details like vibrato, and real-time tracking of voiced speech.