A fast two-microphone noise reduction algorithm based on power level ratio for mobile phone

As an indispensable instrument in today´s daily life, mobile phone that is used in diverse environments suffers from the speech quality degradation due to the presence of background noises. In this paper, we propose a novel two-microphone noise reduction system based on the power level ratio (PLR) of the observed signals. In the system, a primary microphone is placed close to the talker´s mouth and an auxiliary microphone is placed away. The proposed noise reduction algorithm first calculates the ratio of the power of observed signals at the two microphones, and subsequently calculates the spectral gain function based on the power level ratio using the sigmoid function. Experimental results demonstrate that this proposed algorithm yields the much higher speech quality than the state-of-the-art noise-reduction algorithms, and more importantly involves much less computational cost which makes it feasible for mobile phone.