Multi channel speech dereverberation using LP residual cepstrum in an adaptive beamforming framework

In this paper, a novel method of multi channel speech dereverberation using modified generalized sidelobe canceller (MGSC) is proposed. This method utilizes the knowledge of adaptive beamforming (ABF) and linear prediction residual cepstrum (LPRC) technique to perform dereverberation. The LPRC is applied at the beamformed output to generate the signal which still have late reflection components. In addition, the LPRC is also applied at each microphone output to produce reference signals. A relation between the LP residual of the clean and the reverberated speech signal derived in earlier work is used to remove early reflection components from each microphone and beamformer output. This results in effective blocking of the direct path components from the late reflected components. The power envelope (PE) is then obtained for each reference signals and also for the joint ABF and LPRC output. The remaining reverberation components are calculated using these power envelopes. The Post processing is finally used to remove late reverberation components from joint ABF and LPRC output. Experiments on speech dereverberation and distant speech recognition are conducted at various direct to reverberant ratios (DRR) and compared to methods available in literature to illustrate the significance of this method.