A robust front-end algorithm for distributed speech recognition

This paper presents the robust front-end algorithm that was submitted by Motorola to the ETSI STQ-Aurora DSR working group as a proposal for the Advanced DSR front-end in January 2001. The algorithm consists of a two-stage melwarped Wiener filter, a waveform processor, a channelnormalized mel-frequency cepstral calculation and a subsystem of post-cepstral processing according to the reliability of mel-spectral components, etc. The output of this algorithm, a set of Mel-Frequency Cepstral Coefficients (MFCC), is compressed and encoded based on ETSI ES 201 108 standard; and then it is transmitted at 4800 bps. Compared to ETSI standard MFCC front-end, the proposed algorithm delivers an improvement of 42.64% in performance on the Aurora 2 database, which is required by this Eurospeech Special Event. With a very simple frame deletion algorithm based on a Voice-Onset Detection (VOD), the improvements were significantly boosted to 47.58% on the same database. In this paper we also give further insights about the proposal by providing performances and analyses with the Aurora SpeechDat-Car databases.