Expectation-maximization algorithm for multi-pitch estimation and separation of overlapping harmonic spectra

This paper addresses the problem of multi-pitch estimation, which consists in estimating the fundamental frequencies of multiple harmonic sources, with possibly overlapping partials, from their mixture. The proposed approach is based on the expectation-maximization algorithm, which aims at maximizing the likelihood of the observed spectrum, by performing successive single-pitch and spectral envelope estimations. This algorithm is illustrated in the context of musical chord identification.