Patent ID: 8886499

Claim:
A voice processing apparatus comprising: a time-frequency transforming unit which transforms a first voice signal representing a sound captured by a first voice input unit and a second voice signal representing a sound captured by a second voice input unit, respectively, into a first frequency signal and a second frequency signal in a frequency domain on a frame-by-frame basis with each frame having a predefined time length; a phase difference calculation unit which calculates a phase difference between the first frequency signal and the second frequency signal on the frame-by-frame basis for each of a plurality of frequency bands; a detection unit which determines on the frame-by-frame basis for each of the plurality of frequency bands whether or not the phase difference falls within a first range of phase differences that the phase difference can take for a specific sound source direction, thereby obtaining the percentage of the phase difference falling within the first range over a predetermined number of frames, and which detects, from among the plurality of frequency bands, a frequency band for which the percentage does not satisfy a condition corresponding to a sound coming from the sound source direction; a range setting unit which sets, for the frequency band detected by the detection unit, a second range by expanding the first range predefined for the sound source direction; a signal correction unit which produces corrected first and second frequency signals by making the amplitude of at least one of the first and second frequency signals larger when the phase difference falls within the second range than when the phase difference falls outside the second range; and a frequency-time transforming unit which transforms the corrected first and second frequency signals, respectively, into corrected first and second voice signals in a time domain.