Embedded speech recognition system on 8-bit MCU core
Dong Wang, Liang Zhang, Jia Liu, Runsheng Liu · 2004
This is a small vocabulary, speaker independent, discrete word speech recognition system based on the system on chip (SOC) philosophy. It is implemented on an 8-bit MCU (micro control unit). The system adopts linear predictive cepstral coefficient (LPCC) related features followed by a vector quantization (VQ) step as the front end, and a hidden Markov model (HMM) as the speech model. Confidence measures based on likelihood scores (LLS) are given for rejection of out-of-vocabulary (OOV) words. The recognition rate is improved with corrective training, and robustness is acquired by integrating the confidence measure into the system. The recognition accuracy is nearly 97% with a vocabulary up to 30 phrases under normal conditions. A simple speech codec is also implemented for all speech I/O purposes.