A predominant-F/sub 0/ estimation method for CD recordings: MAP estimation using EM algorithm for adaptive tone models

This paper describes a predominant-F/sub 0/ (fundamental frequency) estimation method called PreFEst, which can detect melody and bass lines in monaural audio signals containing sounds of various instruments, While most previous methods premised mixtures of a few sounds and had difficulty dealing with such complex signals, our method can estimate the F/sub 0/ of the melody and bass lines without assuming the number of sound sources in compact-disc recordings. In this paper we propose the following three extensions to our previous PreFEst to make it more adaptive and flexible: introducing multiple harmonic-structure tone models, estimating the shape of tone models, and introducing a prior distribution of its shape and F/sub 0/ estimates These extensions were implemented by the MAP (maximum a posteriori probability) estimation by using the expectation-maximization algorithm. Experimental results with compact-disc recordings showed that our real-time system based on the extended PreFEst achieved performance improvement.