Smoothed unit HMM in mandarin speech recognition

The base unit in mandarin speech recognition can be phoneme, demi-syllable or syllable. Demi-syllable system has fewer HMM models and need less computation, thus it's suitable for real-time systems. But due to poor description for the acoustic properties of the speech signal, it generally shows a low performance compared to syllable system. While system based on syllable of phoneme (tri-phone or di-phone) has much more HMM models, and needs massive computation in training and recognition. In this paper, a compromised scheme is proposed. The new system is based on demi-syllable, but the two demi-syllable HMMs are connected into a full syllable HMM in training phase,so the data of the whole length of the syllable are used, and smoothing between two demi-syllables is introduced. This can increase the system performance without increasing HMM models, and it fits to real-time systems with DSP kernel.