Naturally Sounding Speech Synthesis and Recognition Based on the Formulation of Prosody

本研究的主要目的是建立语音韵律特征与语言信息、帕拉语言信息和非语言信息之间的关系，实现语音合成的先进技术。通过对基频轮廓进行低通滤波，抑制重音成分，并取其偏差，提高了从基频轮廓中自动提取短语成分起始点的准确性。利用从语言信息中获得的韵律知识作为约束F0参数估计的自动韵律标记方法进一步提高了准确性。2.为类对话语音合成构建了莫拉时长规则。这些规则基本上是在韵律短语的基础上将阅读式言语的每个莫拉时长修改为对话式言语的时长，由FO轮廓定义。不同态度言语的韵律特征 ...更多信息 的情绪进行了分析。研究发现，说话人有选择地控制几个韵律线索来表达态度/情感的程度。通过知觉实验还发现，情感语音的实现也离不开音段特征控制.提出了一种用莫拉单元码表示韵律词的F0曲线并对其转换进行统计建模的方法（莫拉转换统计模型）。韵律词边界的检测率为70-75%，插入错误为11-15%。将该方法应用于连续语音识别，莫拉识别率提高了%。提出了一种基于重音类型和短语边界位置的句子F0轮廓生成方法.提出了一种基于韵律特征的大词汇量连续语音识别波束搜索过程中的动态剪枝方法。实验证明，在不降低识别率的情况下，搜索空间可以减少到四分之一。该方法在韵律边界处增大波束宽度，在边界之间减小波束宽度。提出了一种基于韵律边界信息的音素模型选择方法.基于所获得的结果，一个口语对话系统的学术信息检索的开发和评估。少

Several results including the following ones were achieved through the study aiming at formulating the relationship between prosodic features of speech and linguistic and para/non linguistic information, and realizing advanced technologies on speech synthesis :1. An improved accuracy was realized in automatic extraction of phrase component onsets from fundamental frequency (FO) contours by suppressing accent components through low-pass filtering of the contours and by taking their deviations. Further improvements in accuracy were realized in a method of automatic prosodic labeling where knowledge on prosody obtainable from linguistic information was utilized as constrictions F0 parameter estimation.2. Mora duration rules were constructed for dialogue-like speech synthesis. These rules are basically to modify each mora duration of reading-style speech to that of dialogue-like speech in prosodic phrase-basis, defined by the FO contours.3. Prosodic features of Speech with various attitude … More s/emotions were analyzed. It was found that a speaker selectively controlling several prosodic cues to express degree of attitudes/emotion. It was also found through a perceptual experiment that segmental feature control were also indispensable to realized emotional speech.4. A method was developed to represent F0 contours of prosodic words by codes in mora unit and to model their transitions statistically (Statistic model of moraic transition). The detection rates of 70-75% were achieved with insertion errors of 11-15% for prosodic word boundaries. The method was applied to continuous speech recognition with few % improvements in mora recognition rates. A method was also developed to generate sentence F0 contours with inputs of accent types and phrase boundary positions.5. A prosodic feature-based method was developed for the dynamic pruning in beam search process of large-vocabulary continuous speech recognition. It was proved that the search space could be reduced to a quarter without degradation in recognition rates. The method enlarges beam width at prosodic boundaries and decreases between boundaries. A method was also developed to select phoneme models with various context dependencies using prosodic boundary information.6. Based on the results obtained, a spoken dialogue system of academic information retrieval was developed and evaluated. Less