Open Access

An FFT-Based Companding Front End for Noise-Robust Automatic Speech Recognition

  • Bhiksha Raj1Email author,
  • Lorenzo Turicchia2,
  • Bent Schmidt-Nielsen1 and
  • Rahul Sarpeshkar2
EURASIP Journal on Audio, Speech, and Music Processing20072007:065420

https://doi.org/10.1155/2007/65420

Received: 29 November 2006

Accepted: 23 April 2007

Published: 26 June 2007

Abstract

We describe an FFT-based companding algorithm for preprocessing speech before recognition. The algorithm mimics tone-to-tone suppression and masking in the auditory system to improve automatic speech recognition performance in noise. Moreover, it is also very computationally efficient and suited to digital implementations due to its use of the FFT. In an automotive digits recognition task with the CU-Move database recorded in real environmental noise, the algorithm improves the relative word error by 12.5% at -5 dB signal-to-noise ratio (SNR) and by 6.2% across all SNRs (-5 dB SNR to +5 dB SNR). In the Aurora-2 database recorded with artificially added noise in several environments, the algorithm improves the relative word error rate in almost all situations.

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Authors’ Affiliations

(1)
Mitsubishi Electric Research Laboratories (MERL)
(2)
Massachusetts Institute of Technology

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Copyright

© Bhiksha Raj et al. 2007

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.