| Nara Institute of Science and Technology National University Corporation Patent applications |
| Patent application number | Title | Published |
|---|
| 20120134508 | Audio Processing Apparatus - An audio processing apparatus generates a suppression coefficient sequence that is composed of coefficient values corresponding to frequency components of an audio signal, the frequency components being multiplied by the corresponding coefficient values to suppress noise components of the audio signal. In the audio processing apparatus, a characteristic value calculation unit calculates a noise characteristic value depending on a shape of a magnitude distribution of the audio signal. An intensity setting unit variably sets a suppression intensity of the noise components based on the noise characteristic value. A coefficient sequence generation unit generates the suppression coefficient sequence based on the audio signal and the suppression intensity. | 05-31-2012 |
| 20100296665 | NOISE SUPPRESSION APPARATUS AND PROGRAM - A In a noise suppression apparatus, an extractor extracts a noise component from an audio signal. A stationary noise estimator estimates stationary noise included in the noise component. A first noise suppressor removes a spectrum of the stationary noise from a spectrum of the audio signal to an extent determined by a subtraction factor. A non-stationary noise estimator estimates a spectrum of non-stationary noise by subtracting the spectrum of the stationary noise from the spectrum of the noise component. A factor setter generates a filtering factor for emphasizing a target sound component contained in the audio signal from the spectrum of the non-stationary noise. A second noise suppressor performs a filtering process using the filtering factor on the audio signal after processing of the first noise suppressor. An index calculator calculates a kurtosis change index representing an extent of change of kurtosis in a frequence distribution of magnitude of the audio signal between the kurtosis observed when processing of the first noise suppression part is performed and the kurtosis observed when processing of the second noise suppression part is performed. A factor adjuster variably controls the subtraction factor according to the kurtosis change index. | 11-25-2010 |
| 20100008520 | Noise Suppression Estimation Device and Noise Suppression Device - A noise suppression estimation device calculates a noise index value which varies according to kurtosis of a frequence distribution of magnitude of a sound signal before or after suppression of the noise component, the noise index value indicating a degree of occurrence of musical noise after suppression of the noise component in a frequency domain. For example, the noise suppression estimation device calculates first kurtosis of a frequence distribution of magnitude of the sound signal before suppression of the noise component, calculates second kurtosis of a frequence distribution of magnitude of the sound signal after suppression of the noise component, and calculates the noise index value from the first kurtosis and the second kurtosis. | 01-14-2010 |
