Improved musical pitch tracking using principal decomposition analysis

We present a technique for improving the performance of a method for estimating the time-varying fundamental frequency (pitch) of a musical signal corrupted by interference components. The original method, developed by M. Piszczalski and B.A. Galler (1979), involves the calculation and comparison of frequency-pair ratios from each spectrum within a time-frequency transform of the corrupted signal. As the strength of the interference components is increased, the frequency estimates from this method become more unreliable. To obtain improved performance we developed a transform conditioning procedure that enhances the harmonic signal's spectral components in a constant-Q transform prior to the calculation of frequency-pair ratios. This transform conditioning technique is based on a method we have previously developed for principal decomposition analysis of time-frequency transforms