Under-modelled blind system identification for time delay estimation in reverberant environments

Abstract

In multichannel systems, acoustic time delay estimation (TDE) is a challenging problem in reverberant environments. Although blind system identification (BSI) based methods have been proposed which utilize a realistic signal model for the room impulse response (RIR), their TDE performance depends strongly on that of the BSI, which is often inaccurate in practice when the identified responses are under-modelled. In this paper, we propose a new under-modelled BSI based method for TDE in reverberant environments. An under-modelled BSI algorithm is derived, which is based on maximizing the cross-correlation of the cross-filtered signals rather than minimizing the cross-relation error, and also exploits the sparsity of the early part of the RIR. For TDE, this new criterion can be viewed as a generalization of conventional cross-correlationbased TDE methods by considering a more realistic model for the early RIR. Depending on the microphone spacing, only a short early part of each RIR is identified, and the time delays are estimated based on the peak locations in the identified early RIRs. Experiments in different reverberant environments with speech source signals demonstrate the effectiveness of the proposed method.

Direct-Path Signal Cross-Correlation Estimation for Sound Source Localization in Reverberation

“…Time delays among microphone signals are then computed from the direct paths in the estimated RIRs to give an SSL result. An under-modelled BSI based method is proposed in [22], which estimates the early RIRs instead of the whole impulse responses. In addition, relative transfer function (RTF) based methods [23][24][25][26] are developed by generalising the anechoic steering vector into the RTF, and the RTF can be estimated by solving a set of linear equations to obtain the least square solutions.…”