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

하나의 IMU를 이용한 앉은 자세 분류 연구

김연욱(Y. W. Kim),조우형(W. H. Cho),전유용(Y. Y. Jeon),이상민(S. M. Lee) 한국재활복지공학회 2017 재활복지공학회논문지 Vol.11 No.3

바르지 못한 앉은 자세는 다양한 질병과 신체 변형을 유발한다. 하지만 오랜 시간동안 바른 앉은 자세를 유지하는 것은 쉬운 일이 아니다. 이러한 이유 때문에 그동안 자동으로 바른 앉은 자세를 유도하기 위한 다양한 시스템이 제안되어왔다. 이전에 제안되었던 앉은 자세 판별 및 바른 앉은 자세 유도 시스템은 영상 처리를 이용한 방법, 의자에 압력센서를 달아 측정하는 방법, IMU(Internal Measurement Unit)를 이용한 방법이 있었다. 이 중 IMU를 이용한 측정 방법은 하드웨어 구성이 간단하고, 공간, 광량 등의 환경적 제한이 적어 측정에 있어서 용이한 이점이 있었다. 본 논문에서는 하나의 IMU를 이용하여 적은 데이터로 효율적으로 앉은 자세를 분류하는 방법을 연구하였다. 특징추출 기법을 이용하여 데이터 분류에 기여도가 낮은 데이터를 제거하였으며, 머신러닝 기법을 이용하여 앉은 자세 분류에 적합한 센서 위치를 찾고, 여러 개의 머신러닝 모델 중 가장 분류 정확도가 높은 머신러닝 모델을 선정하였다. 특징추출 기법은 PCA(Principal Component Analysis)를 사용하였고, 머신러닝 모델은 SVM(Support Vector Machine), KNN(K Nearest Neighbor), K-means (K-means Algorithm) GMM (Gaussian Mixture Model), and HMM (Hidden Marcov Model)모델을 사용하였다. 연구결과 데이터 분류율이 높게나온 뒷목이 적합한 센서 위치가 되었으며, 센서 데이터 중 Yaw데이터는 분류 기여도가 가장 낮은 데이터임을 PCA 특징추출 기법을 이용하여 확인하고, 제거하여도 분류율에 영향이 매우 작음을 확인하였다. 적합 머신러닝 모델은 SVM, KNN 모델로 다른 모델에 비하여 분류율이 높게 나오는 것을 확인할 수 있었다. Bad sitting postures are known to cause for a variety of diseases or physical deformation. However, it is not easy to fit right sitting posture for long periods of time. Therefore, methods of distinguishing and inducing good sitting posture have been constantly proposed. Proposed methods were image processing, using pressure sensor attached to the chair, and using the IMU (Internal Measurement Unit). The method of using IMU has advantages of simple hardware configuration and free of various constraints in measurement. In this paper, we researched on distinguishing sitting postures with a small amount of data using just one IMU. Feature extraction method was used to find data which contribution is the least for classification. Machine learning algorithms were used to find the best position to classify and we found best machine learning algorithm. Used feature extraction method was PCA(Principal Component Analysis). Used Machine learning models were five : SVM(Support Vector Machine), KNN(K Nearest Neighbor), K-means (K-means Algorithm) GMM (Gaussian Mixture Model), and HMM (Hidden Marcov Model). As a result of research, back neck is suitable position for classification because classification rate of it was highest in every model. It was confirmed that Yaw data which is one of the IMU data has the smallest contribution to classification rate using PCA and there was no changes in classification rate after removal it. SVM, KNN are suitable for classification because their classification rate are higher than the others.

말운동장애인을 위한 시-청각 단서 제공 읽기 훈련 프로그램 개발

방동혁,전유용,양동권,길세기,권미선,이상민,Bang, D.H.,Jeon, Y.Y.,Yang, D.G.,Kil, S.K.,Kwon, M.S.,Lee, S.M. 대한의용생체공학회 2008 의공학회지 Vol.29 No.4

In this paper, we developed a visual-auditory cue software for reading training of motor speech disorder patients. Motor speech disorder patients can use the visual and/or auditory cues for reading training and improving their symptom. The software provides some sentences with visual-auditory cues. Our sentences used for reading training are adequately comprised on modulation training according to a professional advice in speech therapy field. To ameliorate reading skills we developed two algorithms, first one is automatically searching the starting time of speech spoken by patients and the other one is removing auditory-cue from the recorded speech that recorded at the same time. The searching of speech starting time was experimented by 10 sentences per 6 subjects in four kinds of noisy environments thus the results is that $7.042{\pm}8.99[ms]$ error was detected. The experiment of the cancellation algorithm of auditory-cue was executed from 6 subjects with 1 syllable speech. The result takes improved the speech recognition rate $25{\pm}9.547[%]$ between before and after cancellation of auditory-cue in speech. User satisfaction index of the developed program was estimated as good.

CIC형 보청기용 범용 이어쉘 제작을 위한 파라미터 추출 및 시뮬레이션

에르덴바야르,전유용,박규석,송영록,이상민,U, Erdenebayar.,Jeon, Y.Y.,Park, G.S.,Song, Y.R.,Lee, S.M. 대한의용생체공학회 2010 의공학회지 Vol.31 No.4

Most of the ear shells of hearing aids are manufactured manually, and it is one of the reasons that the cost of the custom-made hearing aids can be increased. Thus it is required to manufacture the ready-made ear shell for the purpose of easy manufacturing and decrease in cost. In this study, we extract parameters in order to manufacture the ready-made ear shell for CIC type hearing aids and simulate to reconstruct the ear shell using the extracted parameters. To parameter extraction, we set up the eleven parameters for the ready-made ear shell based on anatomical characteristics of the ear canal, and we found values of the parameters from twenty-one impressions in their 20s and twelve impressions in their 60s using aperture detection and feature detection algorithms. Classifying the parameters by size, we also determine the parameters of ready-made ear shell into three types for people in their 20s and two types for people in their 60s. Each ready-made ear shell was simulated to reconstruct using figured parameters, and evaluated the rate of agreement with unused impressions for setting parameters. To evaluate the ready-made ear shell, we calculate the volume ratio and intersection between of the each impression and ready-made ear shell, and the intersection ratio using the intersection volume and ready-made ear shell volume. As a result, the volume ratio was about 70%, and volume match ratio was also up to 70%. It means that the ready-made ear shell we simulated is the significantly matched to impression.

자동이득 조절에서 해제시간에 따른 어음인지점수 변화

황세미,전유용,박헌진,송영록,이상민,Hwang, S.M.,Jeon, Y.Y.,Park, H.J.,Song, Y.R.,Lee, S.M. 대한의용생체공학회 2010 의공학회지 Vol.31 No.5

Automatic gain control(AGC) is used in hearing aids to compensate for the hearing level as to reduced dynamic range. AGC is consisted of the main 4 factors which are compression threshold, compression ratio, attack time, and release time. This study especially focus on each individual need for optimum release time parameters that can be changed within 7 certain range such as 12, 64, 128, 512, 2094, and 4096ms. To estimate the effect of various release time in AGC, twelve normal hearing and twelve hearing impaired listeners are participated. The stimuli are used by one syllable and sentence which have the same acoustic energy respectively. Then, each of score of the word recognition score is checked in quiet and noise conditions. As a result, it is verified that most people have the different best recognition score on specific release time. Also, if hearing aids is set by the optimum release time in each person, it is helpful in speech recognition and discrimination.

비대칭 청각 필터의 음성처리 평가에 관한 기초 연구

주상익(S. I. Joo),전유용(Y. Y. Jeon),이상민(S. M. Lee) 한국재활복지공학회 2009 한국재활복지공학회 학술대회논문집 Vol.2009 No.10

It is well-known that the shapes of auditory filter are asymmetrical and different with each center frequency and each input level. In this study, the asymmetrical auditory filter was simulated and then some tests to estimate the filter objectively were performed. In the test, each pure tone with each center frequency was multiplied to auditory filter with similar center frequency to pure tone. Output sound was evaluated using PESQ which is predict subjective speech quality objectively. As a result of the test, the maximum difference of PESQ value among center frequency of the auditory filer was 0.45. It means that the difference of the shape auditory filter may affected to speech quality.

지그비를 이용한 크로스 보청기 설계

임원진(W. J. Lim),전유용(Y. Y. Jeon),송영록(Y. R. Song),한영환,이상민(S. M. Lee) 한국재활복지공학회 2009 한국재활복지공학회 학술대회논문집 Vol.2009 No.10

Implementation of contralaterar routing of signal hearing aid using ZigBee is presented in this paper, that has the ability of lower power operation than that of WIF1 and less interference than that of FM. ZigBee CROS hearing aid consists of transmission part and receiving part. Transmission part sends signal with antenna. Receiving part acquires signal with antenna and make sound with speaker. ZigBee CROS hearing aid shows a good operation compare with receiving and transmitting signal from each part.

난청인의 난청 정도에 따른 비대칭 청각 필터 구현의 객관적 평가

주상익(S. I. Joo),전유용(Y. Y. Jeon),송영록(Y. R. Song),이상민(S. M. Lee) 한국재활복지공학회 2009 재활복지공학회논문지 Vol.3 No.1

난청인의 청력 손실은 개인별로 다양하므로 기존의 대칭적으로 주파수 밴드별 청각 필터를 구현하는 방법은 다양한 형태의 난청인의 청력 손실을 적절하게 모사해주지 못한다. 각 중심주파수와 음성의 입력크기에 따라 청각 필터의 형태가 비대칭적으로 바뀌고 청력손실이 있는 난청인은 청력 손실에 따라 청각필터의 형태가 정상인들과는 다른 형태로 바뀌게 되며 음질에도 차이가 있다. 본 연구에서는 난청인의 난청 정도에 따라 변하는 비대칭 청각 특성을 잘 반영한 청각필터를 구현하여 몇 가지 실험을 통해 각 구현된 청각 필터의 성능을 객관적으로 평가하였다. 실험은 구현된 청각 필터를 통한 음성의 perceptual evaluation of speech quality (PESQ)와 log likelihood ratio (LLR)를 사용하였으며 그 값을 통해 처리된 음성의 객관적인 음질과 왜곡정도를 평가 하였다. 청력 손실을 주었을 때 대칭과 비대칭 청각 필터사이의 PESQ와 LLR 값을 실험해 본 결과 청각 필터 간의 큰 차이를 보였다. 위 실험 결과들로 대칭과 비대칭 청각 필터의 형태에 따라서 음성의 음질에 영향을 받는다는 것을 알 수 있었다. 특히, 난청이 있을 때 중심 주파수별 청각 필터의 비대칭적 형태 변화가 난청인이 받아들이는 음질에 영향이 있었다. Hearing impaired person s hearing loss has personally various shape, so existing symmetrical auditory filter of frequency band method wasn"t properly simulated the hearing impaired person"s various hearing loss shape. The shapes of auditory filter are asymmetrical different with each center frequency and each input level. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. In this study, the asymmetrical auditory filter was simulated and then some tests to estimate the filter"s performance objectively were performed. The experiment as simulated auditory filter"s performance evaluation method used perceptual evaluation of speech quality (PESQ) and log likelihood ratio (LLR) for speech through auditory filter. In the test, processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference between symmetrical and asymmetrical auditory filter. It means that the difference of the shape auditory filter may affect to speech quality. Especially, when hearing loss existed, auditory filter changing according to asymmetrical shape for each center frequency affected to perceive speech quality of the hearing impaired.

잡음제거 기능을 갖춘 시-청각 단서 제공 읽기 훈련 프로그램

방동혁(D. H. Bang),전유용(Y. Y. Jeon),양동권(D. G. Yang),길세기(S. K. Kil),권미선(M. S. Kwon),이상민(S. M. Lee) 한국재활복지공학회 2008 한국재활복지공학회 학술대회논문집 Vol.2008 No.11

In this paper, we developed a visual-auditory cue software for reading training of motor speech disorder patients. Motor speech disorder patients can use the visual and/or auditory cues for reading training and improving their symptom. The software provides some sentences with visual-auditory cues. Our sentences used for reading training are adequately comprised on modulation training according to a professional advice in speech therapy field. To ameliorate reading skills we developed two algorithms, first one is automatically searching the starting time of speech spoken by patients and the other one is removing auditory-cue from the recorded speech that recorded at the same time. Finally, the noise in the recorded speech has been removed by noise cancellation algorithm.