Faculty Profiles - NISIMURA Ryuichi

Misc - NISIMURA Ryuichi

Division display141 - 160 of about 368／ All the affair displays >>

ウェブ集合知に基づいた語彙獲得と3-gram確率推定による言語モデル自動生成ツール

田中雅康,西村竜一,河原英紀,入野俊夫

日本音響学会2013年春季研究発表会 ( 日本音響学会 ) 197-198 2013.03

環境音認識を応用した情報提供機能を有するモバイルアプリケーションの検討

中西恭介, 津田貴彦, 西村竜一, 河原英紀, 入野俊夫

情報処理学会第75回全国大会 ( 情報処理学会 ) 463-464 2013.03

Accurate Estimation of Compression in Simultaneous Masking Enables the Simulation of Hearing Impairment for Normal-Hearing Listeners

Toshio Irino, Tomofumi Fukawatase, Makoto Sakaguchi, Ryuichi Nisimura, Hideki Kawahara, Roy D. Patterson

BASIC ASPECTS OF HEARING: PHYSIOLOGY AND PERCEPTION ( SPRINGER ) 787 73 - 80 2013 [Refereed]

This chapter presents a unified gammachirp framework for estimating cochlear compression and synthesizing sounds with inverse compression that cancels the compression of a normal-hearing (NH) listener to simulate the experience of a hearing-impaired (HI) listener. The compressive gammachirp (cGC) filter was fitted to notched-noise masking data to derive level-dependent filter shapes and the cochlear compression function (e.g., Patterson et al., J Acoust Soc Am 114:1529-1542, 2003). The procedure is based on the analysis/synthesis technique of Irino and Patterson (IEEE Trans Audio Speech Lang Process 14:2222-2232, 2006) using a dynamic cGC filterbank (dcGC-FB). The level dependency of the dcGC-FB can be reversed to produce inverse compression and resynthesize sounds in a form that cancels the compression applied by the auditory system of the NH listener. The chapter shows that the estimation of compression in simultaneous masking is improved if the notched-noise procedure for the derivation of auditory filter shape includes noise bands with different levels. Since both the estimation and resynthesis are performed within the gammachirp framework, it is possible for a specific NH listener to experience the loss of a specific HI listener.

DOI

Vocal Tract Length Estimation for Voiced and Whispered Speech Using Gammachirp Filterbank

Toshio Irino, Erika Okamoto, Ryuichi Nisimura, Hideki Kawahara

2013 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA) ( IEEE ) 2013 [Refereed]

In this paper, we demonstrate an auditory spectrogram based on a dynamic compressive gammachirp filterbank (GCFB) that enables accurate and robust estimation of vocal tract length (VTL) for both voiced and whispered speech. Normalized VTLs of 21 speakers were derived by using the least squared analysis of their VTL ratios (for all permutations, 420 = P-21(20)) which were estimated by minimizing spectral distances in the auditory spectrograms. The frequency range was selected in the calculation and the range between 500 and 5000 (Hz) was most reasonable for both speech mode. The method based on GCFB was better than that based on the mel-frequency filterbank (MFFB). The estimated VTLs were compared with the VTL data measured in MRI to confirm the reliability.

Optimizing the simultaneous estimation of frequency selectivity and compression using notched-noise maskers with asymmetric levels

Tomofumi Fukawatase, Toshio Irino, Ryuichi Nisimura, Hideki Kawahara, Roy D. Patterson

Proceedings of Meetings on Acoustics ( Acoustical Society of America (ASA) ) 19 2013 [Refereed]

It is important for the development of hearing aids and other audio devices to estimate the frequency selectivity and compression of the auditory filter accurately. Previously, we reported a technique for estimating the compression of the auditory filter that combined data from a simultaneous notched-noise experiment and a temporal masking curve (TMC) experiment. Unfortunately, the TMC data derived for individual listeners in forward masking is not stable
the cue to the presence of the signal is not entirely clear in forward masking. In this paper, we report attempts to make the traditional simultaneous notched-noise technique more sensitive to the effects of cochlear compression by varying the relative levels of the noise bands. Asymmetric-level maskers (ALMs) make it possible to estimate the filter shape and compression of the auditory filter simultaneously and reliably
the slope of the input-output function is substantially lower than with symmetric-level maskers. We also describe a procedure for incorporating a sensitivity analysis into the filter-fitting process to determine the minimum number of notched-noise conditions required to produce reliable estimates of selectivity and compression, in hopes of being able to employ the technique with hearing impaired listeners. © 2013 Acoustical Society of America.

DOI

Estimated relative vocal tract lengths from vowel spectra based on fundamental frequency adaptive analyses and their relations to relevant physical data of speakers

Mayuko Kobayashi, Ryuichi Nisimura, Toshio Irino, Hideki Kawahara

Proceedings of Meetings on Acoustics ( Acoustical Society of America (ASA) ) 19 2013 [Refereed]

A Japanese vowel database of males, females and children speakers (385 speakers in total) along with relevant physical data (Deguchi et.al. 2011) was analysed using a set of F0 adaptive procedures, which were developed for a speech analysis, modification and synthesis framework TANDEM-STRAIGHT (Kawahara et.al. 2008) and its extensions. By restricting spectral region in estimating ratios for VTLN (vocal tract length normalization), cepstrally weighted distance measure yielded estimates with 2% standard error, by assuming relative vocal tract lengths estimated using regression analysis as the ground truth. A set of regression analyses of the estimated relative vocal tract lengths, average F0s, ages, gender and physical data (speakers' height, weight) were conducted. The results suggest that the proposed analysis procedures applied to the Japanese five vowels may provide sufficient information for estimating speakers' physical data. Possible applications of the proposed estimation procedures will also be discussed. © 2013 Acoustical Society of America.

DOI

Open Answer Scoring for S-CAT Automated Speaking Test System Using Support Vector Regression

Yutaka Ono, Misuzu Otake, Takahiro Shinozaki, Ryuichi Nisimura, Takeshi Yamada, Kenkichi Ishizuka, Yasuo Horiuchi, Shingo Kuroiwa Chiba, Shingo Imai

APSIPA Annual Summit and Conference 2012 ( Asia-Pacific Signal and Information Processing Association (APSIPA) ) 1 - 4 2012.12 [Refereed]

ウェブ上の言語情報で拡張した語彙に基づく 3-gram モデル自動生成ツール

田中雅康,西村竜一,河原英紀,入野俊夫