METHOD FOR PROCESSING NOISY SPEECH SIGNAL, APPARATUS FOR SAME AND COMPUTER-READABLE RECORDING MEDIUM

摘要

Provided are a noise estimation method of a noisy speech signal, an apparatus for the same, and a computer-readable recording medium. The noise estimation method of a noisy speech signal according to one embodiment of the present invention includes a step of transforming an input noisy speech signal into a frequency domain to obtain a transformed spectrum, a step of smoothing the difference of size of the transformed spectrum between neighboring frames to obtain a smoothed size spectrum, a step of obtaining a search frame of the present frame by using only the search frame of the previous frame and/or the spectrum having a smaller size from among the search frame of the previous frame and the smoothed size spectrum of the previous frame and the smoothed size spectrum of the present frame, a step of obtaining an identifying ratio which represents the ratio of noise components included in the input noisy speech signal by using the smoothed size spectrum and the search spectrum, and a step of obtaining a noise spectrum through a recursive averaging technique using an adaptive forget factor defined by the identifying ratio. The noise estimation method of the embodiment of the present invention reduces the volume of calculation for noise estimation and eliminates the necessity of a large-volume memory, thus resulting in the simple implementation in hardware or software, and further it can carry out adaptive procedures for each sub-band of frequency, thereby improving accuracy of noise estimation.