Separation of harmonic structures based on tied Gaussian mixture model and information criterion for concurrent sounds

A method for the separation of harmonic structures of cochannel input concurrent sounds is described. A model for multiple harmonic structures is constructed with a mixture of tied Gaussian mixtures, from which a single harmonic structure is modeled. Our algorithm enables estimation of both the number and the shape of the underlying harmonic structures, based on a maximum likelihood estimation of the model parameters using the EM algorithm and an information criterion. It operates without restriction on the number of mixed sounds and varieties of sound sources, and extracts accurate fundamental frequencies continuously with simple procedures in the spectral domain. Experiments showed high performance of the algorithm for both simultaneous speech and polyphonic music.