研究者詳細 - 水町　光徳

論文 - 水町　光徳

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LPC残差駆動歌唱システムにおける音韻性除去による音質改善の検討査読有り

姫野剛至, 田中裕人, 水町光徳, 松井謙二, 中藤良久

産業応用工学会論文誌 ( 一般社団法人産業応用工学会 ) 4 ( 1 ) 19 - 25 2016年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

We propose a singing system to transmit the pseudo-vocal sound source into the vocal tract. In this paper, we examine the pseudo-vocal sound source that is suitable for singing system. So we carried out a comparison of LPC residual wave and Bark-LPC residual wave that the phonological component included in pseudo-vocal sound source was removed by Bark spectrum. As a result, we found that although the singing voice using Bark-LPC residual is in the low natural tendencies, the Bark-LPC residual wave can reproduce a higher speaker information contributed by the speaker characteristics.

DOI： 10.12792/jjiiae.004.01.04

CiNii Article

CiNii Research

その他リンク： https://ci.nii.ac.jp/naid/130005263509

Study on the improvement of intelligibility for elderly speech using formant frequency shift method 査読有り

Tanaka Y., Mizumachi M., Nakatoh Y.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 9811 LNCS 683 - 690 2016年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© Springer International Publishing Switzerland 2016. In general, aging is progressing in developed countries. Elderly people have difficulty controlling their articulation accurately due to aging. We need to improve the quality of elderly speech for smooth communication. In this paper, we analyzed the 1st formant frequency (F1) and 2nd formant frequency (F2) between the more intelligible speech and less intelligible speech of Japanese elderly people. In addition, we improved the intelligibility of less intelligible elderly speech by using the formant frequency shift method. This method is the correcting by shift value of formant frequency based on LPC. The shift value is the magnification such as expanding the F1-F2 size of less intelligible speech.

DOI： 10.1007/978-3-319-43958-7_83

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84984829622&origin=inward

Acoustical Sensing of Approaching Vehicle by Non-Linear Filtering 査読有り

M. Mizumachi

Proc. 12th Western Pacific Acoustics Conference 2015 (WESPAC) 2015年12月

Design of elder-friendly auditory signals for microwave ovens 査読有り

Kadota N., Mizumachi M., Nakatoh Y.

2015 4th International Conference on Informatics, Electronics and Vision, ICIEV 2015 2015年11月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2015 IEEE. Recent house electrical appliances generate a number of auditory signals, when a user operates an appliance or an appliance draws attention to a user. In this paper, we focus on multi-functional microwave ovens, which commonly have several auditory signals for user's operation, error occurrence, completion of cooking, and so on. A wide variety of auditory signals for current microwave ovens have two problems: it is difficult for users to image what the auditory signals inform, and the auditory signals including high frequency components are not friendly for elderly users. In this paper, popular auditory signals for microwave ovens were subjectively evaluated with/without an elderly-simulated band-pass filter, which simulated an averaged audiogram of elder people, on the five grade scales of easiness of perception, unpleasantness, and emergency. Experimental results suggest that young and elderly people might imagine different function for a single auditory signal. Finally, suitable auditory signals both for young and elderly users are proposed in the viewpoints of frequency and temporal patterns.

DOI： 10.1109/ICIEV.2015.7333977

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84961778212&origin=inward

Perceptual restoration of intermittent speech under noisy environments 査読有り

M. Mizumachi; S. Motomura; T. Takakura; T. Horiuchi

Proc. 22nd International Congress on Sound and Vibration (ICSV22) 2015年07月

Subjective evaluation of high resolution audio under in-car listening environments 査読有り

Mizumachi M., Yamamoto R., Niyada K.

138th Audio Engineering Society Convention 2015 1 60 - 64 2015年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

High resolution audio (HRA) becomes increasingly popular both for music production and consumers. It enables to record a music performance in a wide-band and precise digital audio format. It is, however, unclear in its perceptual advantage under some listening environments. In this study, listening tests were carried out inside cars, where 34 participants listened to the same music in four different audio formats. The participants chose an audio format with better quality in paired comparison among 192 kHz/24 bits PCM, 48 kHz/16 bits PCM, and two kinds of lossy-compressed MPEG audio formats. The participants, who are familiar with HRA and live music performance, could significantly discriminate among the audio formats.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84943236951&origin=inward

文字入力を用いた発話支援システムの開発査読有り

濱井裕也, 水町光徳, 中藤良久, 松井謙二

産業応用工学会論文誌 ( 一般社団法人産業応用工学会 ) 3 ( 1 ) 10 - 17 2015年01月

記述言語：日本語掲載種別：研究論文（学術雑誌）

Utterance is very important for us to communicate with others. However, many people have speech handicaps and can't produce utterance smoothly. They mainly rely on writing and sign language for communication. But they are not easy skills for them to master. In order to help them, we developed a new utterance support system which can function through an information terminal. We made predictions which includes two additional functions of fixed phrase dictionary and the class 2-gram – one of the statistical approaches for processing natural language. Fixed phrase dictionary includes phrases often used in our daily life conversations and class 2-gram uses co-occurrence frequencies of parts of speech in Japanese. There are two purposes for us to use class 2-gram, one is to generate next candidates and the other is to change frequency. We concluded two evaluation experiments. The results show that our system needs less numbers of inputs in helping with written utterance production and using our prototype permits us to input more characters in one minute than using iPhone IME. Hereafter, we intend to create more effective dictionaries and develop new GUI to make our system more effective and faster.

DOI： 10.12792/jjiiae.003.01.02

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005263536

単語発話音声の周波数特徴の加齢変化 (福祉情報工学)

緒方一仁, 水町光徳, 中藤良久

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 ( 一般社団法人電子情報通信学会 ) 114 ( 261 ) 49 - 54 2014年10月

記述言語：日本語掲載種別：研究論文（研究会，シンポジウム資料等）

日本を含む先進諸国では,高齢化が深刻な社会問題となっている.加齢は,音声コミュニケーションにも影響を及ぼす.聴覚の加齢変化については精力的に研究が行われてきたが,発話器官の加齢変化についてはまだ明らかになっていない.本稿では,発話器官の加齢変化に着目し,発話音声の静的特徴について検討する.分析に用いた音声は,64歳から87歳までの男性話者21名による日本語単語発話である.各単語の語頭母音に対して,パワースペクトルを算出し,20代話者と高齢者話者グループの平均と分散を比較した.本分析の結果,加齢により2.5kHzから4.5kHzの周波数帯域でのパワー減少と,4.5kHz以上でのパワー上昇を確認し,すべての音素において周波数特性が平坦になることが判明した.

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110009958972

Robust Sensing of Approaching Vehicles Relying on Acoustic Cue 査読有り

M. Mizumachi, A. Kaminuma, N. Ono, and S. Ando

Proc. IEEE IS3C2014 Paper No. 265 2014年06月

Robust Sensing of Approaching Vehicles Relying on Acoustic Cue 査読有り

M. Mizumachi, Atsunobu Kaminuma, Nobutaka Ono, and Shigeru Ando

Sensors 14 ( 6 ) 9546 - 9561 2014年05月

Applicability of perceptual evaluation of speech quality in evaluating heavily distorted speech 査読有り

Mizumachi M.

137th Audio Engineering Society Convention 2014 224 - 229 2014年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Speech quality assessment is indispensable to properly design a speech enhancement algorithm. Perceptual evaluation of speech quality (PESQ) is frequently employed as an objective speech distortion measure. The PESQ is a methodology for estimating subjective assessment of speech distortion caused by speech codecs for telephony systems. In case of noise reduction, however, a degree of speech distortion is heavier than those caused by the speech codecs. In this paper, applicability of the PESQ is investigated for noisy and noisereduced speech signals under severe noisy conditions. A relationship between PESQ scores and subjective mean opinion scores reveals that the PESQ can be applicable for heavily distorted speech only under nonstationary noisy conditions.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84938854653&origin=inward

Perceptual restoration of intermittent speech relying on illusory continuity 査読有り

Mizumachi M., Motomura S., Takakura T., Horiuchi T.

Proceedings of Forum Acusticum 2014-January 2014年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

A digital communication network makes our daily lives comfortable. It, however, causes a serious problem in speech communication due to a packet loss, which yields intermittent speech after decoding the packets. Packet loss concealment (PLC) is indispensable to achieve smooth speech communication over a digital network. There are various kinds of PLC methods based on wave substitution and feature prediction. Those methods aim to achieve intact restoration of a speech waveform. The ITU-T Recommendation G.711 offers a standard PLC method, but cannot conceal the packet loss, of which lost duration exceeds 60 ms. Then, G.711 PLC method is not enough to cope with the actual packet loss problem. On the other hand, the authors have proposed a perceptual restoration scheme of intermittent speech. We can listen to intermittent speech smoothly, when its gap is filled out with a loud, wide-band noise such as a white noise. This is an auditory illusion called illusory continuity, and is explained as the environmental adaptability of the human brain. In order to employ the illusory continuity for PLC, it is necessary to decrease the harshness of the loud gap-filling noise. A speech-like gap-filling signal is prepared with a mixture of less-harsh environmental noises in advance. Both dynamic and static properties of speech are incorporated into the proposed gap-filling signal. The feasibility of the proposed PLC method was examined by a listening test. Participants gave five-grade mean opinion scores on the smoothness of the restored speech, noisiness of the gap-filling signal, and the easiness of speech perception. It is confirmed that the proposed method has a significant advantage over the G.711 PLC method under long-term packet loss conditions.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84953311058&origin=inward

加齢による聴覚と発話の相互作用 (福祉情報工学)

水町光徳

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 ( 一般社団法人電子情報通信学会 ) 113 ( 272 ) 61 - 66 2013年10月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（研究会，シンポジウム資料等）

高齢化は大きな社会問題であり、加齢による音声コミュニケーションに生じる障害も切実な問題である。加齢による聴力低下は、60歳代以前にも見受けられるが、70歳を超えると急激に高周波数成分の聴力閾値が上昇する。70歳代では、聴覚障害の自覚がなくても、加齢による高音障害型感音性難聴と診断されることが多い。これにより、子音が聴き取りづらくなったり、雑音のなかでの音声の聞き取り能力が低下する。一方、音声知覚において、我々は、声からある程度の年齢を推定できる。つまり、我々は、聴覚的印象として、高齢者音声らしさを表す複数の特徴を知っている。その一つが嗄声であり、これは高齢者音声を特徴付ける聴感印象として数多く報告されている。著者は、高周波数帯域における発話エネルギー上昇が、嗄声の音響的特徴であることを確認した。従来の研究では、高齢者の聴力特性と音声の音響的特徴は、それぞれ独立して調査されてきた。本稿では、「ことばの鎖」を拠り所として、加齢による聴力低下と発話音声変形の相互作用について総合的に検討する。

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110009783062

Speech enhancement by non-linear beamforming tolerant to misalignment of target source direction 査読有り

H. Hayashi, M. Mizumachi, Y. Nakatoh

Journal of the Institute of Industrial Applications Engineers 1 ( 2 ) 97 - 104 2013年10月

Investigation on objective quality evaluation for heavily distorted speech 査読有り

Mizumachi M.

134th Audio Engineering Society Convention 2013 668 - 672 2013年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Demand for evaluating speech quality is on the increase. It is advisable for evaluating the speech quality to employ the common objective measure for the wide variety of adverse speech signals. Unfortunately, current speech quality measures do not suit for heavily distorted speech signals. In this paper, both the applicability and the limit of the perceptual evaluation of speech quality (PESQ) are investigated compared with the subjective mean opinion score (MOS) for noise-added and noise-reduced speech signals. It is found that the PEAQs are compatible with the MOSs for the noise-reduced speech signals in the non-stationary noise conditions.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84883431685&origin=inward

How do we perceive noisy and noise-reduced speech? 査読有り

M. Mizumachi

Proc. Inter-noise 2013年09月

Restoration of intermittent speech based on human auditory capability and temporal characteristics of speech 査読有り

M. Mizumachi, S. Motomura, T. Takakura, and T. Horiuchi

Proc. 20th International Congress on Sound and Vibration (ICSV20) 2013年07月

Relationship Between Subjective and Objective Evaluation of Noise-reduced Speech With Various Widths of Temporal Windows 査読有り

M. Mizumachi

Proc. 21st International Congress on Acoustics Paper ID: 1aSCb13 2013年06月

Investigation on objective quality evaluation for heavily distorted speech 査読有り

M. Mizumachi

Proc. AES 134th Convention CD-ROM (Paper ID: 8830) 2013年05月

How do we perceive noisy and noise-reduced speech? 査読有り

Mizumachi M.

42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life 6 4818 - 4823 2013年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

It is important for speech applications to quantify the intelligibility and the quality of speech. There are some means of evaluating the intelligibility and the quality objectively and subjectively. The objective evaluation is economical, but the general-use distortion measure is not available. On the other hand, the subjective evaluation requires a cost-consuming formal listening test. The right evaluation should be carried out in the right purpose. No almighty methodology has been established at the moment. In this paper, brain activities involved in evaluating the noisy and noise-reduced speech are measured using the functional magnetic resonance imaging (fMRI) technique. It is found that the brain activity in evaluating the noise-reduced speech varies depending on the noise reduction approach. The noise-reduced signals, which are obtained by the linear processing such as the delay- And-sum beamforming, calm down the brain activity compared with the noisy speech signals. On the other hands, non-linear signal processing such as the spectral subtraction activates the auditory cortex intensely. It is necessary for designing the advanced speech distortion measure to independently consider how the noise is removed and how the speech is distorted by noise reduction.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84904515025&origin=inward

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