NOISE GATE, SOUND COLLECTION DEVICE, AND NOISE REMOVAL METHOD

摘要

Provided is a noise gate which can output a sound signal from which only a stationary noise has been removed without degrading the utterance voice of a speaker. A sound collection device (1) includes: an FFT processing unit (11); a noise gate (12), and an IFFT processing unit (13).  The sound collection unit (1) converts a collected sound signal (NE'T) into a frequency spectrum (NE'N) by the FFT processing unit (11).  The noise gate (12) estimates a noise spectrum (N'N) of the stationary noise according to the frequency spectrum (NE'N) of the sound signal.  If the ratio of the frequency spectrum (NE'N) of the sound signal with respect to the signal level of the noise spectrum (N'N) is smaller than a threshold value, the noise gate (12) reduces the signal level (gain) of the sound signal before outputting the signal.  The sound collection device (1) outputs a sound signal (CO'T) generated in the IFFT processing unit (13) by reverse-transforming the frequency spectrum (CO'N) from which the stationary noise (N'N) has been removed.