Patent ID: 8467538

Claim:
A dereverberation apparatus that removes a reverberation signal from an observation signal by applying a dereverberation filter to the observation signal, the observation signal being obtained by collecting an audio signal emitted from a sound source, comprising: a sound source model storage that stores a sound source model that represents the audio signal in the form of a time-varying complex normal distribution model having an average of 0 and no correlation between frequency bands; a dividing unit that divides the observation signal into a plurality of frequency-specific observation signals each corresponding to one of a plurality of frequency bands; an estimating unit that determines a dereverberation filter for a corresponding frequency band by using the frequency-specific observation signal for the corresponding frequency band on the basis of the sound source model and a reverberation model that represents a relationship among the audio signal, the observation signal and the dereverberation filter for the corresponding frequency band; a removing unit that determines a frequency-specific target signal for a corresponding frequency band by applying the dereverberation filter for the corresponding frequency band determined by the estimating unit to the frequency-specific observation signal for the corresponding frequency band; and an integrating unit that integrates the frequency-specific target signals.