Kodrasi, Ina and Doclo , Simon (2018) Improving the conditioning of the optimization criterion in acoustic multi-channel equalization using shorter reshaping filters. EURASIP journal on advances in signal processing, 2018 (11). ISSN 1687-6180

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Abstract

In acoustic multi-channel equalization techniques, such as complete multi-channel equalization based on the multiple-input/output inverse theorem (MINT), relaxed multi-channel least-squares (RMCLS), and partial multi-channel equalization based on MINT (PMINT), the length of the reshaping filters is generally chosen such that perfect dereverberation can be achieved for perfectly estimated room impulse responses (RIRs). However, since in practice the available RIRs typically differ from the true RIRs, this reshaping filter length may not be optimal. This paper provides a mathematical analysis of the robustness increase of equalization techniques against RIR perturbations when using a shorter reshaping filter length than conventionally used. Based on the condition number of the (weighted) convolution matrix of the RIRs, a mathematical relationship between the reshaping filter length and the robustness against RIR perturbations is established. It is shown that shorter reshaping filters than conventionally used yield a smaller condition number, i.e., a higher robustness against RIR perturbations. In addition, we propose an automatic non-intrusive procedure for determining the reshaping filter length based on the L-curve. Simulation results confirm that using a shorter reshaping filter length than conventionally used yields a significant increase in robustness against RIR perturbations for MINT, RMCLS, and PMINT. Furthermore, it is shown that PMINT using an optimal intrusively determined reshaping filter length outperforms all other considered techniques. Finally, it is shown that the automatic non-intrusively determined reshaping filter length in PMINT yields a similar performance as the optimal intrusively determined reshaping filter length.

Item Type:	Article
Additional Information:	Publiziert mit Hilfe des DFG-geförderten Open Access-Publikationsfonds der Carl von Ossietzky Universität Oldenburg.
Uncontrolled Keywords:	Speech dereverberation, Condition number, Reshaping filter length, L-curve
Subjects:	Science and mathematics > Physics Technology, medicine, applied sciences > Medicine and health
Divisions:	Faculty of Medicine and Health Sciences > Department of Medical Physics and Acoustics
Date Deposited:	01 Aug 2018 10:16
Last Modified:	28 Aug 2018 06:56
URI:	https://oops.uni-oldenburg.de/id/eprint/3660
URN:	urn:nbn:de:gbv:715-oops-37417
DOI:	10.1186/s13634-018-0532-1
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