Direction-of-Arrival Based SNR Estimation for Dual-Microphone Speech Enhancement

In this paper, we propose a method for estimating target speech by exploring the spatial cues in adverse noise environments. This method is able to reliably estimate the signal-to-noise ratio (SNR) using the phase difference obtained from dual-microphone signals. To this end, spatial cues such as the phase difference are used to estimate the target-to-non-target directional signal ratio (TNR). Based on the estimated TNR, a direction-of-arrival (DOA)-based SNR is then estimated by using a statistical model-based log-likelihood ratio test for the target speech activity decision followed by a decision-directed approach. The estimate is then incorporated into a Wiener filter in order to obtain a spectral-gain attenuator. The perceptual evaluation of speech quality shows that the performance of a dual-microphone speech enhancement system employing the proposed estimation method outperforms single- and dual-microphone speech enhancement systems that use conventional methods such as Wiener filtering, beamforming, or phase-error-based filtering under noise conditions whose SNR ranges from 0 to 20 dB.