A MFCC-Based CELP Speech Coder for Server-Based Speech Recognition in Network Environments

Existing standard speech coders can provide speech communication of high quality while they degrade the performance of speech recognition systems that use the reconstructed speech by the coders. The main cause of the degradation is that the spectral envelope parameters in speech coding are optimized to speech quality rather than to the performance of speech recognition. For example, mel-frequency cepstral coefficient (MFCC) is generally known to provide better speech recognition performance than linear prediction coefficient (LPC) that is a typical parameter set in speech coding. In this paper, we propose a speech coder using MFCC instead of LPC to improve the performance of a server-based speech recognition system in network environments. However, the main drawback of using MFCC is to develop the efficient MFCC quantization with a low-bit rate. First, we explore the interframe correlation of MFCCs, which results in the predictive quantization of MFCC. Second, a safety-net scheme i...

• Type: Journal
• Year: 2007
• Where: IEICET
• Authors: Jae Sam Yoon, Gil Ho Lee, Hong Kook Kim
• Keywords: Coder, IEICET 2007, Speech Coder, Speech Recognition