The paper presents a new method for dereverberation of speech signals with a single microphone. For applications such as speech recognition, reverberant speech causes serious problems when a distant microphone is used in recording. This is especially severe when the reverberation time exceeds 0.5 s. We propose a method which uses the fundamental frequency (F/sub 0/) of the target speech as the primary feature for dereverberation. This method initially estimates F/sub 0/ and the harmonic structure of the speech signal and then obtains a dereverberation operator. This operator transforms the reverberant signal to its direct signal based on an inverse filtering operation. Dereverberation is achieved without prior knowledge of either the room acoustics or the target speech. Experimental results show that the dereverberation operator estimated from 5240 Japanese word utterances could effectively reduce the reverberation when the reverberation time is longer than 0.1 s.
['Tomohiro Nakatani', 'Masato Miyoshi']
Blind dereverberation of single channel speech signal based on harmonic structure