Phase reference for the generalized multichannel Wiener filter

Abstract

The multichannel Wiener filter (MWF) is a well-established noise reduction technique for speech processing. Most commonly, the speech component in a selected reference microphone is estimated. The choice of this reference microphone influences the broadband output signal-to-noise ratio (SNR) as well as the speech distortion. Recently, a generalized formulation for the MWF (G-MWF) was proposed that uses a weighted sum of the individual transfer functions from the speaker to the microphones to form a better speech reference resulting in an improved broadband output SNR. For the MWF, the influence of the phase reference is often neglected, because it has no impact on the narrow-band output SNR. The G-MWF allows an arbitrary choice of the phase reference especially in the context of spatially distributed microphones. In this work, we demonstrate that the phase reference determines the overall transfer function and hence has an impact on both the speech distortion and the broadband output SNR. We propose two speech references that achieve a better signal-to-reverberation ratio (SRR) and an improvement in the broadband output SNR. Both proposed references are based on the phase of a delay-and-sum beamformer. Hence, the time-difference-of-arrival (TDOA) of the speech source is required to align the signals. The different techniques are compared in terms of SRR and SNR performance.

Low-Complexity Methods for Estimation After Parameter Selection

“…In cognitive radio (CR) communications [4], [5], for example, the selection of parameters of interest may be based on the signal to noise ratio (SNR), signal energy, or transmission rate, and the parameters to be estimated could be channel gain and noise variance of the selected channel. In speech enhancement Nadav Harel and Tirza Routtenberg applications [6], a preliminary stage of reference microphone selection is conducted. In neuroimaging analysis [7], [8], a subset of voxels in the brain may be selected for further analysis based on their activity pattern in functional scans.…”

“…Nadav Harel has been funded by the Kreitman School of Advanced Graduate Studies. applications [6], a preliminary stage of reference microphone selection is conducted. In neuroimaging analysis [7], [8], a subset of voxels in the brain may be selected for further analysis based on their activity pattern in functional scans.…”