高品質な株価音声合成装置の開発とデジタルラジオ放送での試験運用

摘要

NHKの「株式市況」は，ラジオ第2放送で平日17時から放rn送されている番組で，45分の間に，東証一部に上場していrnる約1,500の銘柄のうち約830の銘柄の終値と前日比を伝えrnている．%The 'Kabushiki Shikyo' program, broadcast on NHK Radio 2, reports on the daily closing prices and net changes of about 830 stocks listed on the Tokyo Stock Exchange. Reading out the numerical values within the allotted broadcast time without making mistakes can be extremely difficult for the announcers. We have therefore developed a prototype voice synthesizer for stock-price bulletins, which uses numerical speech synthesis and automatic speech-rate conversion. Our prototype system has been used in experimental digital terrestrial radio broadcasts since October 2006. This article describes the generation of texts to build the speech waveform database, the mechanism used to synthesize numerical speech via the database, the evaluation of naturalness of synthesized speech samples, and the prototype system currently being used by experimental digital terrestrial radio.