A complexity reduction of ETSI advanced front-end for DSR

In Oct. 2002, Advanced Front-End (AFE) for Distributed
Speech Recognition (DSR) was standardized by ETSI. In order
to use AFE feature on low computational resource devices, we
propose a novel approach to improve the computational
efficiency. In our new algorithm, the structure of two-stage melwarped
Wiener filtering algorithm, which is the main part of
AFE, is modified. Wiener filter is constructed and applied
directly in mel-warped filter-bank domain. The measures we
take make many time-consuming operations in original
algorithm completely unnecessary, including the re-calculations
of power spectrum and the time-domain convolution operations.
Consequently, a large amount of computations are saved.
Experiments show that the new approach can substantially
reduce the computation load while preserving the excellent
performance of the ETSI AFE.