A Hybrid Coherence Model for Noise Reduction in Reverberant Environments

In this letter, we propose a novel dual-microphone technique for enhancement of speech degraded by background noise and reverberation. Our algorithm is based on a prediction of the coherence function between the noisy input signals, considering both direct and reverberant speech and noise components received by the sensors, and therefore, is capable of dealing with both coherent and diffuse noise. After predicting the coherence function, the signal to noise ratio (SNR) can be estimated by solving a quadratic equation obtained from the real and imaginary parts of the function. Objective evaluation in a room with reverberation time T₆₀ = 465 ms, demonstrated noticeable improvements in SNR and quality of the outputs processed with the proposed algorithm over the baseline (front microphone), as well as a recently proposed coherence-based noise reduction algorithm.