프레임 기반의 포먼트 강조에 의한 음향 마스킹 현상 발생에 대한 연구

전유용,김규성,이상민,Jeon, Yu-Yong,Kim, Kyu-Sung,Lee, Sang-Min 대한의용생체공학회 2009 의공학회지 Vol.30 No.6

One of the characteristics of the hearing impaired is that their frequency selectivity is poorer than that of the normal hearing. To compensate this, formant enhancement algorithms and spectral contrast enhancement algorithms have been developed. However in some cases, these algorithms fail to improve the frequency selectivity of the hearing impaired. One of the reasons is the acoustic masking among enhanced formants. In this study, we tried to enhance the formants based on the individual masking characteristic of each subject. The masking characteristic used in this study was minimum level difference (MLD) between the first formant to the second formant while acoustic masking was occurred. If the level difference between the two formants in each frame is larger than the MLD, the gain of the first formant was decreased to reduce the acoustic masking that occurred among formants. As a result of the speech discrimination test, using formant enhanced speeches, speech discrimination score (SDS) of the speeches having differently enhanced formants was significantly superior to SDS of the speeches having equally enhanced formants. It means that suppression of the acoustic masking among formants improve frequency selectivity of the hearing impaired.

보청기를 위한 IMCRA 기반 저연산 음성 향상 알고리즘

전유용,이상민 한국재활복지공학회 2017 재활복지공학회논문지 Vol.11 No.4

In this paper, we proposed a low-complexity speech enhancement algorithm based on a improved minima controlled recursive averaging (IMCRA) and log minimum mean square error (logMMSE). The IMCRA algorithm track the minima value of input power within buffers in local window and identify the speech presence using ratio between input power and its minima value. In this process, many number of operations are required. To reduce the number of operations of IMCRA algorithm, minima value is tracked using time-varying frequency-dependent smoothing based on speech presence probability. The proposed algorithm enhanced speech quality by 2.778%, 3.481%, 2.980% and 2.162% in 0, 5, 10 and 15dB SNR respectively and reduced computational complexity by average 9.570%. 본 논문에서는 향상된 최소값 제어 재귀 평균 (improved minima controlled recursive averaging, IMCRA) 알고리즘과 로그 최소값 평균 제곱 오차 (log minimum mean square error, logMMSE)를 기반으로 한 저연산 음성 향상 알고리즘을 제안한다. IMCRA 알고리즘은 버퍼를 이용하여 일정 구간에서 입력 신호 전력의 최소값을 추적하고 최소값과 입력 신호의 비율을 통해 음성 존재를 확인한다. 이러한 과정에서 많은 연산이 필요하며 연산량을 줄이기 위해서 음성 존재 확률을 기반으로한 주파수 밴드별 시변 스무딩으로 최소값을 추적한다. 제안된 알고리즘은 0dB, 5dB, 10dB 그리고 15dB 신호 대 잡음비에서 평균 2.778%, 3.481%, 2.980% 그리고 2.162% 음성 품질이 향상되었으며, 평균 9.570% 연산량이 감소한 것을 확인하였다.

韓國學生漢語聲調偏誤原因分析

전유용 ( You Yong Qian ) 한국중국언어학회 2008 중국언어연구 Vol.0 No.26

On the Origin of -l Coda in Sino-Korean

錢有用(Qian Youyong) 중국어문학연구회 2016 중국어문학논집 Vol.0 No.98

This paper aims to shed light on the origin of -l coda in Sino-Korean by examining the transliteration of Sanskrit place names in Wang o Cheonchuk guk jeon 往五天竺國傳 (Memoir of the Pilgrimage to the Five Kingdoms of India) written by Hyecho 慧超(704-783 AD). By comparing the transliteration in Xuanzang’s 玄奘 Datang Xiyuji 大唐西域記(Records on the Western Regions) and that in Wang o Cheonchuk guk jeon, we find that the alveolar consonant (non-nasal) coda in Hyecho’s language is rather close to the [l] sound. We propose that the [t] coda in Middle Chinese has been probably pronounced as [l] (or [r]) in the phonological system of the language spoken in Silla 新羅(57BC-935 AD) in the early 8th century. The result of this research, to a certain extant, argues against the influential hypothesis that the -l coda in Sino-Korean originated from the –r in the northwestern dialect of Middle Chinese in the late Tang Dynasty.

韓國學生漢語聲調偏誤聲學分析

전유용 ( You Yong Qian ) 한국중국언어학회 2007 중국언어연구 Vol.0 No.25

인간의 심리음향 특성을 이용한 잡음 제거 및 음성 향상 알고리즘

전유용(Yuyong Jeon),송영록(Youngrok Song),황세미(Hwan Semi),박규석(Kyuseok Park),안홍섭(Hongsub An),이상민(Sangmin Lee) 한국HCI학회 2011 한국HCI학회 학술대회 Vol.2011 No.1

보청기에서 음성 대비 강조에 의해 발생할 수 있는 마스킹 현상

전유용(Y. Y. Jeon),양동권(D. G. Yang),방동혁(D. H. Bang),길세기(S. K. Kil),이상민(S. M. Lee) 한국재활복지공학회 2007 재활복지공학회논문지 Vol.1 No.1

디지털 보청기에서의 포먼트 강조에 의한 마스킹 효과 연구

전유용(Yuyong Jeon),길세기(Se-kee Kil),윤광섭(Kwang-sub Yoon),이상민(Sangmin Lee) 대한전자공학회 2008 電子工學會論文誌-SC (System and control) Vol.45 No.5

청력 손실을 보상하고 난청인이 다른 사람들과 대화할 수 있도록 디지털 보청기 알고리즘은 개발 되어 왔음에도 불구하고, 디지털 보청기 사용자들은 음성을 듣는데 어려움이 있다고 불만을 토로한다. 그 이유는 피드백이나 잔여 노이즈 등에 의해 디지털 보청기를 통한 음성의 질이 이해하기에 불충분하기 때문이다. 또 다른 이유로 포먼트들 사이에서 일어나는 마스킹 현상이 될 수 있다. 이 연구에서 정상 청각 피험자와 노인성 난청을 갖고 있는 난청인 피험자의 마스킹 특성을 측정하여 음성에서의 마스킹에 의한 음성 인지 저하를 확인하기 위한 실험을 하였다. 실험은 순음검사, 어음 청취 역치 검사, 낱말 분별력 검사, 순음 마스킹 검사, 어음 마스킹 검사의 5개 테스트로 이루어졌다. 어음 마스킹 검사에서 각각 어음 세트에 25개의 어음이 사용되었다. 각 어음의 왜곡을 객관적으로 평가하기 위해서 log likelihood ratio (LLR)를 도입하였다. 결과적으로 포먼트 향상의 양을 늘리면 늘릴수록 어음 인지는 낮아졌고, 각 어음 세트에서 각각의 향상된 어음은 통계적으로 비슷한 LLR을 갖지만 어음인지는 그렇지 않게 나타났다. 이것은 왜곡이 아닌 음향 마스킹이 어음 인지에 영향을 준다는 것을 의미한다. 실제로 피험자들 대부분이 맞추지 못한 음성을 주파수 분석한 결과 첫 번째와 두 번째 포먼트 사이의 레벨 차이가 약 35dB이며 이는 순음 마스킹 실험 결과(정상 청각 피험자:36.36dB, 난청인 피험자:32.86dB)와 비슷한 양상을 보였다. 실험 결과에서 볼 수 있듯이 음향마스킹의 특성은 정상 청각인과 난청인 사이에서 다르게 나타난다. 그렇기 때문에 보청기 착용 전 마스킹 특성을 검사하고, 피팅 시에 적용해야 한다. Although digital hearing aid algorithms have been developed to compensate hearing loss and to help hearing impaired people to communicate with others, digital hearing aid user still complain about difficulty of hearing the speech. The reason could be the quality of speech through digital hearing aid is insufficient to understand the speech caused by feedback, residual noise and etc. And another thing is masking effect among formants that makes sound quality low. In this study, we measured the masking characteristics of normal listeners and hearing impaired listeners having presbyacusis to confirm masking effect in speech itself. The experiment is composed of 5 tests; pure tone test, speech reception threshold (SRT) test, word recognition score (WRS) test, puretone masking test and speech masking test. In speech masking test, there are 25 speeches in each speech set. And log likelihood ratio (LLR) is introduced to evaluate the distortion of each speech objectively. As a result, the speech perception became lower by increasing the quantity of formant enhancement. And each enhanced speech in a speech set has statistically similar LLR, however speech perception is not. It means that acoustic masking effect rather than distortion influences speech perception. In actuality, according to the result of frequency analysis of the speech that people can not answer correctly, level difference between first formant and second formant is about 35dB, and it is similar to result of pure tone masking test(normal hearing subject:36.36dB, hearing impaired subject:32.86dB). Characteristics of masking effect is not similar between normal listeners and hearing impaired listeners. So it is required to check the characteristics of masking effect before wearing a hearing aid and to apply this characteristics to fitting.

從韓國漢字音看漢語元音的高化和裂化

錢有用(Qian, Youyong) 중국어문학연구회 2021 중국어문학논집 Vol.- No.130

This paper summarized the Mandarin pronunciations of the corresponding characters of Sino-Korean open syllables that consist of vowels [o] or [u], identified the initials and finals of these characters in Middle Chinese, and provided an analysis of the sound change of relevant rhymes in Chinese, with special reference to vowel raising and split. The value of this study is two-fold. First, the result of this study may be of help to Korean learners of Chinese in the acquisition of the pronunciations of these rhymes in Mandarin. Second, it is known that vowel shift and split has been seen in Chinese from Old Chinese to Modern Chinese. By comparing the performance of relevant rhymes in Sino-Korean and Chinese, this paper provided evidence regarding the route of the vowel raising and split in Chinese.

심리음향 특성을 이용한 음성 향상 알고리즘

전유용(Yuyong Jeon),이상민(Sangmin Lee) 대한전기학회 2010 전기학회논문지 Vol.59 No.6

In the speech system, for example hearing aid as well as speech communication, speech quality is degraded by environmental noise. In this study, to enhance the speech quality which is degraded by environmental speech, we proposed an algorithm to reduce the noise and reinforce the speech. The minima controlled recursive averaging (MCRA) algorithm is used to estimate the noise spectrum and spectral weighting factor is used to reduce the noise. And partial masking effect which is one of the human hearing properties is introduced to reinforce the speech. Then we compared the waveform, spectrogram, Perceptual Evaluation of Speech Quality (PESQ) and segmental Signal to Noise Ratio (segSNR) between original speech, noisy speech, noise reduced speech and enhanced speech by proposed method. As a result, enhanced speech by proposed method is reinforced in high frequency which is degraded by noise, and PESQ, segSNR is enhanced. It means that the speech quality is enhanced.