8th Annual Conference of the International Speech Communication Association

Antwerp, Belgium
August 27-31, 2007

Mel Sub-Band Filtering and Compression for Robust Speech Recognition

Babak Nasersharif (1), Ahmad Akbari (1), Mohammad Mehdi Homayounpour (2)

(1) Iran University of Science & Technology, Iran
(2) Amirkabir University of Technology, Iran

The Mel-frequency cepstral coefficients (MFCC) are commonly used in speech recognition systems. But, they are high sensitive to presence of external noise. In this paper, we propose a noise compensation method for Mel filter bank energies and so MFCC features. This compensation method is performed in two stages: Mel sub-band filtering and then compression of Mel-sub-band energies. In the compression step, we propose a sub-band SNR-dependent compression function. We use this function in place of logarithm function in conventional MFCC feature extraction in presence of additive noise. Results show that the proposed method significantly improves MFCC features performance in noisy conditions where it decreases average word error rate up to 30% for isolated word recognition on three test sets of Aurora 2 database.

Full Paper

Bibliographic reference.  Nasersharif, Babak / Akbari, Ahmad / Homayounpour, Mohammad Mehdi (2007): "Mel sub-band filtering and compression for robust speech recognition", In INTERSPEECH-2007, 1102-1105.