Transono Inc.

Sung Il Jung

Dong Gyung Ha

A noise estimation method for a noisy speech signal according to an embodiment of the present invention includes the steps of approximating a transformation spectrum by transforming an input noisy speech signal to a frequency domain, calculating a smoothed magnitude spectrum having a decreased difference in a magnitude of the transformation spectrum between neighboring frames, calculating a search spectrum to represent an estimated noise component of the smoothed magnitude spectrum, and estimating a noise spectrum by using a recursive average method using an adaptive forgetting factor defined by using the search spectrum. According to an embodiment of the present invention, the amount of calculation for noise estimation is small, and large-capacity memory is not required. Accordingly, the present invention can be easily implemented in hardware or software. Further, the accuracy of noise estimation can be increase because an adaptive procedure can be performed on each frequency sub-band.

Method for processing noisy speech signal, apparatus for same and computer-readable recording medium

Provided are a noise state determination method and an apparatus and a computer readable recording medium therefor. A noisy speech signal processing method according to the present invention includes calculating a transformed spectrum by transforming an input noisy speech signal to a frequency domain; calculating a smoothed magnitude spectrum by reducing magnitude differences of the transformed spectrum between neighboring frames; calculating a search spectrum which represents an estimated noise component of the smoothed magnitude spectrum; and calculating an identification ratio which represents a ratio of a noise component included in the input noisy speech signal, by using the smoothed magnitude spectrum and the search spectrum. Since a small amount of calculation is required and a large-capacity memory is not required, the present invention may be easily implemented as hardware or software. Also, since an adaptive operation is performed with respect to each frequency sub-band, the accuracy of determining a noise state may be improved.

Procedure for processing noisy speech signals, and apparatus and computer program therefor

A sound quality improvement method for a noisy speech signal according to an embodiment of the present invention comprises the steps of estimating a noise signal of an input noisy speech signal by performing a predetermined noise estimation procedure for the noisy speech signal; measuring a relative magnitude difference to represent a relative difference between the noisy speech signal and the estimated noise signal; calculating a modified overweighting gain function with a non-linear structure in which a relatively high gain is allocated to a low-frequency band than a high-frequency band by using the relative magnitude difference; and obtaining an enhanced speech signal by multiplying the noisy speech signal and a time-varying gain function obtained by using the overweighting gain function. Accordingly, the amount of calculation for noise estimation is small, and large-capacity memory is not required. Furthermore, the present invention can be easily implemented in hardware or software, and the accuracy of noise estimation can be increase because an adaptive procedure can be performed on each frequency sub-band.

Growing community of inventors

Ansan-si, South Korea

Sung Il Jung