A new noise reduction system based on ALE and noise reconstruction filter

A noise reduction technique is proposed to reduce wideband and sinusoidal noise in noisy speech. In real environments, the background noise includes sinusoidal noise, for example, from ventilation fans. Therefore, it is also important to reduce sinusoidal noise. The new noise reduction system uses two types of adaptive line enhancer (ALE) and a noise reconstruction filter (NRF). First, two ALEs estimate the speech components. However, since two ALEs cannot estimate unvoiced sound, the quality of the speech enhanced by the two ALEs is not enough. Thus, the NRF is used to improve the noise reduction ability. The NRF accurately estimates the background noise from the signal occupied by the noise components, which is obtained by subtracting the speech enhanced by the two ALEs from the noisy speech. The enhanced speech is obtained by subtracting the reconstructed noise from the noisy speech. Additionally, the noise reduction system with a feedback path is also proposed for more improvement of the quality of the enhanced speech.