SOUND SIGNAL PROCESSING DEVICE AND SOUND SIGNAL PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a sound signal processing method and a sound signal processing device which process an input sound signal including a deteriorated sound such as quantizing noise so as to make the degraded sound subjectively unperceptible. SOLUTION: After a spectrum of a decoded speech as an input sound signal is perceptually weighted, the spectrum is calculated by a transformation strength control unit, and transformation strength is calculated based on the amplitude and continuity of the spectrum. The spectrum of the decoded speech is obtained by a signal transformation unit. Then the amplitude is smoothed, phase disturbance is imparted on the basis of the transformation strength, and the decoded speech is returned to a signal region as a transformed decoded speech. The decoded speech is analyzed, and the likeness of the background noise is calculated by a signal evaluating unit and used as an addition control value. If the addition control value shows the likeness of the background noise, a weighted addition unit reduces the weight upon the decoded speech, increases the weight upon the transformed decoded speech, and performs addition to generate an output speech. COPYRIGHT: (C)2011,JPO&INPIT