A complexity reduction of ETSI advanced front-end for DSR

In October 2002, the advanced front-end (AFE) for distributed speech recognition (DSR) was standardized by ETSI. In order to use the AFE feature on low computational resource devices, we propose a novel approach to improve the computational efficiency. In our new algorithm, the structure of the two-stage mel-warped Wiener filtering algorithm, which is the main part of AFE, is modified. A Wiener filter is constructed and applied directly in the mel-warped filter-bank domain. The measures we take make many time-consuming operations in the 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.