Patent ID: 8239052
Filing Date: 2012-08-07
Classification: G10H

Abstract:
1. A sound source separation system comprising: a musical score information data storage section that stores musical score information data, the musical score information data being temporally synchronized with an input audio signal containing a plurality of instrument sound signals corresponding to a plurality of types of instrument sounds produced from a plurality of types of musical instruments, the musical score information data relating to a plurality of types of musical scores to be respectively played by the plurality of types of musical instruments corresponding to the plurality of instrument sound signals; a model parameter assembled data preparation/storage section that respectively replaces a plurality of single tones contained in the plurality of types of musical scores with a plurality of model parameters to prepare a plurality of types of model parameter assembled data which correspond to the plurality of types of musical scores and which are formed by assembling the plurality of model parameters, and stores the plurality of types of model parameter assembled data in storage means, the plurality of model parameters being prepared in advance to represent a plurality of types of single tones respectively produced from the plurality of types of musical instruments with a plurality of harmonic/inharmonic mixture models each including a harmonic model and an inharmonic model, the plurality of model parameters containing a plurality of parameters for respectively forming the plurality of harmonic/inharmonic mixture models; a first power spectrogram generation/storage section that reads a plurality of the model parameters at each time from the plurality of types of model parameter assembled data to generate a plurality of initial power spectrograms corresponding to the read model parameters using the plurality of parameters respectively contained in the read model parameters and a predetermined first model parameter conversion formula, and that stores the plurality of initial power spectrograms in storage means; an initial distribution function computation/storage section that synthesizes the plurality of initial power spectrograms stored in the first power spectrogram generation/storage section at each time to prepare a synthesized power spectrogram at each time, computes at each time a plurality of initial distribution functions indicating proportions of the plurality of initial power spectrograms to the synthesized power spectrogram at each time, and stores the plurality of initial distribution functions in storage means; a power spectrogram separation/storage section that in a first separation process separates a plurality of power spectrograms corresponding to the plurality of types of musical instruments at each time from a power spectrogram of the input audio signal at each time using the plurality of initial distribution functions at each time, and stores the plurality of power spectrograms in storage means, and that in second and subsequent separation processes separates a plurality of power spectrograms corresponding to the plurality of types of musical instruments at each time from the power spectrogram of the input audio signal at each time using a plurality of updated distribution functions, and stores the plurality of power spectrograms in the storage means; an updated model parameter estimation/storage section that estimates a plurality of updated model parameters from the plurality of power spectrograms separated at each time, the plurality of updated model parameters containing a plurality of parameters necessary to represent the plurality of types of single tones with the harmonic/inharmonic mixture models, and that prepares a plurality of types of updated model parameter assembled data formed by assembling the plurality of updated model parameters, and stores the plurality of types of updated model parameter assembled data in storage means; a second power spectrogram generation/storage section that reads a plurality of the updated model parameters at each time from the plurality of types of updated model parameter assembled data stored in the updated model parameter estimation/storage section to generate a plurality of updated power spectrograms corresponding to the read updated model parameters using the plurality of parameters respectively contained in the read updated model parameters and a predetermined second model parameter conversion formula, and stores the plurality of updated power spectrograms in storage means; and an updated distribution function computation/storage section that synthesizes the plurality of updated power spectrograms stored in the second power spectrogram generation/storage section at each time to prepare a synthesized power spectrogram at each time, computes at each time the plurality of updated distribution functions indicating proportions of the plurality of updated power spectrograms to the synthesized power spectrogram at each time, and stores the plurality updated distribution functions in storage means, wherein the updated model parameter estimation/storage section is configured to estimate the plurality of parameters respectively contained in the plurality of updated model parameters such that the plurality of updated power spectrograms gradually change from a state close to the plurality of initial power spectrograms to a state close to the plurality of power spectrograms most recently stored in the power spectrogram separation/storage section each time the power spectrogram separation/storage section performs the separation process for the second or subsequent time; and the power spectrogram separation/storage section, the updated model parameter estimation/storage section, the second power spectrogram generation/storage section, and the updated distribution function computation/storage section repeatedly perform process operations until the plurality of updated power spectrograms change from the state close to the plurality of initial power spectrograms to the state close to the plurality of power spectrograms most recently stored in the power spectrogram separation/storage section.