Cepstral prefiltering for time delay estimation in reverberant environments

Time delay estimation (TDE) between the signals received by two or more spatially separated microphones can be used as a means for the passive localization of the dominant talker in applications such as audio-conference. However, in a recent study, it has been shown that reverberation can have disastrous effects on TDE performance. In this paper, we develop and evaluate a new cepstral prefiltering technique which can be applied on the microphone signals before the actual TDE in order to obtain a more accurate estimate of the position of a source in a typical reverberant environment. The performance of a TDE system with and without cepstral prefiltering is investigated under controlled conditions via Monte-Carlo simulations. The results clearly demonstrate the beneficial effects of the new cepstral prefiltering technique on TDE performance (i.e., reduction of bias, variance and number of anomalous estimates)