Noise suppression device
A correction spectrum calculation unit 6 obtains a correction spectrum by smoothing an estimated noise spectrum in accordance with the degree of its variations, and a suppression quantity limiting coefficient calculation unit 7 decides a suppression quantity limiting coefficient from the correction spectrum. A suppression quantity calculation unit 9 obtains a suppression coefficient based on the suppression quantity limiting coefficient, and the spectrum suppression unit 10 carries out amplitude suppression of spectral components of an input signal.
1. A noise suppression device which calculates a suppression coefficient for noise suppression using spectral components obtained by converting an input signal from a time domain to a frequency domain and using an estimated noise spectrum estimated from the input signal, which carries out amplitude suppression of the spectral components of the input signal using the suppression coefficient, and which generates a noise suppressed signal converted to the time domain, the noise suppression device comprising:
a correction spectrum calculator that obtains statistical information reflecting a characteristic of the estimated noise spectrum and that generates a correction spectrum by correcting the estimated noise spectrum in accordance with the statistical information;
a suppression quantity limiting coefficient calculator that generates a suppression quantity limiting coefficient for defining upper and lower limits of the noise suppression from the correction spectrum the correction spectrum calculator generates; and
a suppression quantity calculator that controls the suppression coefficient using the suppression quantity limiting coefficient the suppression quantity limiting coefficient calculator generates.
2. The noise suppression device according to claim 1 , wherein
the correction spectrum calculator controls a correction quantity of the estimated noise spectrum in accordance with a value of the statistical information.
3. The noise suppression device according to claim 1 , wherein
the correction spectrum calculator stops correction of the estimated noise spectrum when a value of the statistical information is not greater than a prescribed threshold.
4. The noise suppression device according to claim 1 , wherein
the correction spectrum calculator applies correction of at least one of frequency direction smoothing and interframe smoothing to the estimated noise spectrum.
5. The noise suppression device according to claim 1 , wherein
the correction spectrum calculator carries out correction that enhances smoothing with an increase of frequency to the estimated noise spectrum.