Q.-G. Liu, B. Champagne and P. Kabal
"A microphone array processing technique for speech enhancement in a reverberant space", Speech Communication, vol. 18, pp. 317-334, June 1996.
In this paper, a new microphone array processing technique is proposed for blind dereverberation of speech signals affected by room acoustics. It is based on the separate processing of the minimum-phase and all-pass components of delay-steered multi-microphone signals. The minimum-phase components are processed in the cepstrum-domain, where spacial averaging followed by low-time filtering is applied. The all-pass components, which contain the source location information, are processed in the frequency-domain by performing spacial averaging and by retaining only the all-pass component of the resulting output. The underlying motivation for the new processor is to use spacio-temporal processing over a single set of synchronous speech segments from several microphones to reconstruct the source speech, such that it is applicable to practical time-variant acoustic environments. Simulated room impulse responses are used to evaluate the new processor and to compare it to a conventional beamformer. Significant improvements in array gain and important reductions in reverberation in listening tests are observed.