Low latency dereverberation with considering speech naturalness for hearing aids

It is well known that long reverberation makes speech unclear especially for hearing impaired. For a long time, a lot of researches on dereverberation have been studied. However, the computational cost of most of those methods are too expensive for hearing aids. Therefore, we have proposed the simplified dereverberation method, which can estimate reverberation energy from observed signal. In addition, it is also necessary implementing the processing with low latency to avoid an annoyance for hearing aid wearer. Processed signal have to be natural as much as possible to reduce listening effort, although there is performance limit because of simplicity. In this study, we make two proposals in our previous method. First, we apply Frequency-Warped Filterbank (FWF) in analysis and synthesis systems in order to make frequency bands as Bark scaled alignment, and to take the tolerable latency all over frequency for hearing. Second, we introduce the gain control in each frequency to maintain naturalness of processed speech, because reverberation energy varies depending on frequency bands in actual reverberant environments. From subjective experiments, there was a tendency that they prefer this proposal to the previous method.