Smart noise reduction system based on ALE and noise reconstruction system

The noise reduction technique to reduce wideband and sinusoidal noise in noisy speech is proposed. We have proposed the noise reconstruction system (NRS) using the linear prediction error filter (LPEF) and system identification model. However, since the sinusoidal noise has the characteristic just like the vowel, the conventional system cannot reduce the sinusoidal noise. We introduce the adaptive line enhancer (ALE) to reduce the sinusoidal noise. The ALE estimates a current signal correlated with a delayed signal. The speech signal is nonstationary signal in long time interval. On the other hand, the sinusoidal noise is stationary noise. For example, ventilating fan and engine noise. So the autocorrelation of the sinusoidal noise is maintained although that of the speech signal fades. Thus the ALE can estimate only the sinusoidal noise. Therefore, the noise reduction system based on the ALE and the NRS reduces not only the wideband noise but also the sinusoidal noise.