論文 - 北村 達也
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Acoustic analysis of the vocal tract during vowel production by finite-difference time-domain method 査読あり
Hironori Takemoto, Parham Mokhtari, Tatsuya Kitamura
Journal of the Acoustical Society of America 128 ( 6 ) 3724 - 3738 2010年12月
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Visualisation of hypopharyngeal cavities and vocal-tract acoustic modelling
Kiyoshi Honda, Tatsuya Kitamura, Hironori Takemoto, al
Computer methods in Biomechanics and Biomedical Engineering 13 ( 4 ) 443 - 453 2010年7月
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Yasuhiro Hamada, Tatsuya Kitamura, Masato Akagi
Journal of Signal Processing 14 ( 4 ) 265 - 268 2010年7月
共著
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Similarity of effects of emotions on the speech organ configuration with and without speaking
Tatsuya Kitamura
11TH ANNUAL CONFERENCE OF THE INTERNATIONAL SPEECH COMMUNICATION ASSOCIATION 2010 (INTERSPEECH 2010), VOLS 1-2 909 - 912 2010年
単著
出版者・発行元：ISCA-INST SPEECH COMMUNICATION ASSOC
In this work we propose and verify a hypothesis on emotional speech production: emotions induce physical and physiological changes in the whole body including changes in the configuration and physical/mechanical properties of the speech organs, regardless of whether or not the person is speaking, and as a side effect, this changes the voice quality. To verify this hypothesis, we measured the configuration of the speech organs of professional actors simulating four emotions (neutral, hot anger, joy, and sadness) with and without speaking by magnetic resonance imaging. The results clearly showed that emotions affect the speech organ configuration, and the same tendency of changes in the speech organ configuration was found regardless of whether or not the person was speaking. We also measured electromagnetic articulography data while a participant watched a relaxation or horror movie, and the result implies that emotional changes can deform the speech organ configuration even if the participant does not speak. These results support our hypothesis.
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Transfer functions of solid vocal-tract models constructed from ATR MRI database of Japanese vowel production
Tatsuya Kitamura, Hironori Takemoto, Seiji Adachi, Kiyoshi Honda
Acoustical Science and Technologies 30 ( 4 ) 288 - 296 2009年4月
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Resonance characteristics of hypopharyngeal cavities
Kiyoshi Honda, Tatsuya Kitamura, Hironori Takemoto, Parham Mokhtari, Seiji Adachi
Journal of the Acoustical Society of America 123 ( 5 ) 3731 2008年7月
共著
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MRI-Based Study on Morphological and Acoustic Properties of Mandarin Sustained Vowels
WANG Gaowu, KITAMURA Tatsuya, LU Xugang, DANG Jianwu, KONG Jiangping
J Signal Process 12 ( 4 ) 311 - 314 2008年7月
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Deformation of the hypopharyngeal cavities due to F0 changes and its acoustic effects 査読あり
Hironori Takemoto, Tatsuya Kitamura, Kiyoshi Honda, Shinobu Masaki
Acoustical Science and Technology 2008年4月
共著
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Single-matrix formulation of a time domain acoustic model of the vocal tract with side branches
MOKHTARI Parham, TAKEMOTO Hironori, KITAMURA Tatsuya
Speech Communication 50 ( 3 ) 179 - 190 2008年3月
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Effects of acoustic modification on perception of speaker characteristics for sustained vowels
Tatsuya Kitamura, Takeshi Saitou
Acoustical Science and Technology 2007年6月
共著
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Vocal tract length perturbation and its application to male-female vocal tract shape conversion
Seiji Adachi, Hironori Takemoto, Tatsuya Kitamura, Parham Mokhtari, Kiyoshi Honda
Journal of the Acoustical Society of America 121 ( 6 ) 3874 - 3885 2007年6月
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Principal components of vocal tract area functions and inversion of speech by linear regression of cepstrum coefficient
Parham Mokhtari, Hironori Takemoto, Tatsuya Kitamura, Kiyoshi Honda
Journal of Phonetics 2007年1月
共著
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A bone-conduction system for auditory stimulation in MRI 査読あり
Yukiko Nota, Tatsuya Kitamura, Hironori Takemoto, Hiroyuki Hirata, Kiyoshi Honda, Yasuhiro Shimada, Ichiro Fujimoto, Yuko Syakudo, Shinobu Masaki
Acoustical Science and Technology 2007年1月
共著
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Principal components of vocal-tract area functions and inversion of vowels by linear regression of cepstrum coefficients
Parham Mokhtari, Tatsuya Kitamura, Hironori Takemoto, Kiyoshi Honda
JOURNAL OF PHONETICS 35 ( 1 ) 20 - 39 2007年1月
共著
出版者・発行元：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
This paper addresses the following two hypotheses: (1) vocal-tract area functions of Japanese vowels can be accurately represented by a linear combination of only a few principal components which, furthermore, are similar to those reported in the literature for different languages; and (ii) the principal components' weights can be predicted and area functions thereby accurately estimated from acoustics by linear regression of cepstrum parameters. To test these hypotheses, synchronized acoustic and vocal-tract 3D MRI data were recorded from an adult male Japanese speaker for both sustained and dynamic vowel utterances. The first two principal components explained covariations in vocal-tract shape and length accounting for 94-97% of the total variance, and indeed provided a cross-linguistic validation of the two underlying components of vowel production emergent from the literature. Multiple linear regression models were then evaluated for their accuracy in reconstructing the area functions of the dynamic utterance by predicting the first two PC coefficients, using either carefully measured formants or cepstral coefficients defined in various frequency bands. The best formant-based regression model required all four formants, with a mean adjusted correlation of 0.93 and mean absolute errors of 0.187 cm(2) in area and 0.131 em in vocal-tract length. The best cepstrum-based regression model prescribed 24 cepstral coefficients defined in the frequency band 0-4 kHz, with a mean adjusted correlation of 0.92 and mean absolute errors of 0.102 cm(2) in area and 0.082 cm in vocal-tract length. These results suggest that vowel production features, properly constrained by PCA modeling, can be mapped with sufficient accuracy from easily measured cepstrum parameters. More work is required to reduce the dependence on MRI data, to extend the applicability of these methods to different voice qualities and different speakers, and to select a smaller subset of acoustic parameters for more robust, real-time inversion. (c) 2006 Elsevier Ltd. All rights reserved.
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An MRI-based time-domain speech synthesis system 査読あり
Tatsuya Kitamura, Hironori Takemoto, Parham Mokhtari, Toshio Hirai
Journal of the Acoustical Society of America 120 ( 5 ) 3037 2006年12月
共著
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Changes in vocal tract resonance during a pitch cycle 査読あり
Tatsuya Kitamura, Seiji Adachi
Journal of the Acoustical Society of America 120 ( 5 ) 3351 2006年12月
共著
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光マイクロホンを用いたMRI撮像時の騒音測定
北村 達也, 正木 信夫, 島田 育廣, 藤本 一郎, 赤土 裕子, 本多 清志
日本音響学会誌 62 ( 5 ) 379 - 382 2006年5月
共著
MRI装置の普及と高磁場化に伴い,撮像時の騒音は無視できない問題となっている。しかし,装置内の騒音測定には磁性体を含む一般的な装置を利用することができない。また,強磁場下で利用可能な測定装置を使っても,その一部に導電体が含まれていればRFパルス(電磁波)に起因するノイズが混入する可能性がある。本研究では非導電体のみで構成された光マイクロホンを用いてこの問題を解決し,1.5TのMRI装置を対象にしてSpin-echo T1強調,Fast spin-echo T2強調,RF-FAST,及びSingle-shot EPIの4種の撮像シーケンスの騒音を測定した。その結果,これらの騒音の音圧レベルはそれぞれ112.6dB,112.5dB,107.8dB,110.6dBであった。
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有限要素法による声道伝達特性推定の有効性に関する検討
西本 博則, 赤木 正人, 北村 達也, 鈴木 規子
日本音響学会誌 62 ( 4 ) 306 - 315 2006年4月
共著
有限要素法と声道等価回路モデルの声道伝達特性の推定精度の調査を行うため,MR計測から得られた声道モデルより推定された伝達特性のピークと実音声のホルマントの比較を行った。その結果,健常な被験者では両推定法とも精度良く推定された。一方,複雑で左右非対称な声道形状の被験者では,有限要素法を用いれば音声ホルマントの個数が同じであり,ホルマント周波数と伝達特性のピーク周波数に大きな差がなかったが,等価回路モデルでは伝達特性のピークの数と音声ホルマントの数が一致しなかった。複雑で左右非対称な声道の伝達特性推定には,等価回路モデルは不適切であり,有限要素法が有効であることが示された。
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Acoustic roles of the laryngeal cavity in vocal tract resonance 査読あり
Hironori Takemoto, Seiji Adachi, Tatsuya Kitamura, Parham Mokhtari, Kiyoshi Honda
Journal of the Acoustical Society of America 2006年4月
共著
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Cyclicity of laryngeal cavity resonance due to vocal fold vibration 査読あり
Tatsuya Kitamura, Hironori Takemoto, Seiji Adachi, Parham Mokhtari, Kiyoshi Honda
Journal of the Acoustical Society of America 120 ( 4 ) 2239 - 2249 2006年4月