Dual microphone noise PSD estimation for mobile phones in hands-free position exploiting the coherence and speech presence probability

This contribution addresses the enhancement of noisy speech signals picked up by a dual microphone mobile phone in hands-free position. A novel technique to estimate the noise power spectral density is presented which combines two methods: a single microphone algorithm based on the speech presence probability and a dual microphone technique exploiting the coherence properties of the target signal and the background noise. Due to the novel approach, the weakness of both methods can be overcome. Since the proposed method requires knowledge of the current coherence properties, a technique is presented which estimates the coherence of the speech and noise signals, which is usually not known in practice.