语音合成中基于稳定段边界的不定长基元选取

语音合成技术是人机言语交互中重要的媒介方式,基元选取算法一直是拼接式语音合成中的研究重点.在传统的语音合成中基于代价函数的拼接合成基元选取算法的基础上,将双音子(diphone)的稳定段边界模型应用到单词和音节中,最后使用3种基元模型的分层不定长选音算法,从语料库中优选出最佳合成基元序列拼接合成最终语音.该算法一方面利用分层统一的不定长选音策略,尽可能地选取具有更好韵律特性和声学连续性的较大基元,从而显著减少拼接点,将有可能发生协同发音或者切分错误的拼接点包含到更大的基元内部;另一方面通过稳定段切分修改传统拼接基元边界类型,充分利用了diphone的稳定段边界良好的拼接特性,从而提高了合成语音的连续性和自然度.评测结果显示,这种方法与传统diphone拼接合成方法相比,其合成效果有显著的提升.

Stable Boundary-Based Non-Uniform Unit Selection in Speech Synthesis

Speech synthesis technology plays an important role in human computer interaction. Based on the traditional cost function based unit selection method, this paper proposes an approach that incorporates diphone's stable boundary model into word and syllable, and utilizes multi-layer Viterbi algorithm for selecting the best path from the corpus to generate the final waveforms. With the proposed multi-layer non-uniform unit selection algorithm, the new method can not only choose the longer prosody units which have correct acoustical characteristic to reduce the concatenate points while including the potential coarticulation and bad labeled phones inside the longer units, but also fix the traditional unit boundary type to absorb the diphone's good stable joint character to improve the continuity and naturalness at concatenate boundaries. The evaluation results show that by using this approach, the synthetic speech can achieve great improvements on both naturalness and intelligibility compared with the traditional diphone-based unit selection approach.