On the Global Output SNR of the Parameterized Frequency-Domain Multichannel Noise Reduction Wiener Filter
Mehrez Souden, Jacob Benesty, Sofiène Affes · IEEE Signal Processing Letters · 2010
The parameterized multichannel Wiener filter (PMWF) is known to allow for a flexible tuning of speech distortion and noise reduction. In addition, the output signal-to-noise ratio (SNR) is a natural metric that shows the true effect of such a filter on both residual noise and filtered speech. Earlier contributions have only shown that the output SNR of the Wiener filter is larger than the input SNR (as a proof of its effectiveness). However, the effect of the tuning parameter (denoted as ß following the notation of [1]) on this metric is not yet understood. In this paper, we prove that the global (fullband) output SNR of the PMWF is an increasing function of ß but remains below an asymptotic value. As a byproduct, a very simplified proof of the global output SNR improvement is provided.