Statistical modelling of speech segment duration by constrained tree regression

Naoto Iwahashi, Yoshinori Sagisaka

Research output: Contribution to journalArticle

13 Citations (Scopus)


This paper presents a new method for statistical modelling of prosody control in speech synthesis. The proposed method, which is referred to as Constrained Tree Regression (CTR), can make suitable representation of complex effects of control factors for prosody with a moderate amount of learning data. It is based on recursive splits of predictor variable spaces and partial imposition of constraints of linear independence among predictor variables. It incorporates both linear and tree regressions with categorical predictor variables, which have been conventionally used for prosody control, and extends them to more general models. In addition, a hierarchical error function is presented to consider hierarchical structure in prosody control. This new method is applied to modelling of speech segmental duration. Experimental results show that better duration models are obtained by using the proposed regression method compared with linear and tree regressions using the same number of free parameters. It is also shown that the hierarchical structure of phoneme and syllable durations can be represented efficiently using the hierarchical error function.

Original languageEnglish
Pages (from-to)1550-1559
Number of pages10
JournalIEICE Transactions on Information and Systems
Issue number7
Publication statusPublished - 2000 Jul
Externally publishedYes


ASJC Scopus subject areas

  • Information Systems
  • Computer Graphics and Computer-Aided Design
  • Software

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