In this paper, a new microphone array processing technique is proposed
for blind dereverberation of speech signals affected by room acoustic
s. It is based on the separate processing of the minimum-phase and all
-pass components of delay-steered multi-microphone signals. The minimu
m-phase components are processed in the cepstrum-domain, where spatial
averaging followed by low-time filtering is applied. The all-pass com
ponents, which contain the source location information, are processed
in the frequency-domain by performing spatial averaging and by retaini
ng only the all-pass component of the resulting output. The underlying
motivation for the new processor is to use spatio-temporal processing
over a single set of synchronous speech segments from several microph
ones to reconstruct the source speech, such that it is applicable to p
ractical time-variant acoustic environments. Simulated room impulse re
sponses are used to evaluate the new processor and to compare it to a
conventional beamformer, Significant improvements in array gain and im
portant reductions of reverberation in listening tests are observed.