Browsing by Author "Cheng, Chih-Jen"

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Development of Novel Hearing Aids by Using Image Recognition Technology
(2019-05-01)
Lin, Bor-Shing
;
Liu, Ching-Feng
;
Cheng, Chih-Jen
;
Wang, Jhi-Joung
;
Liu, Chengyu
Speech is easily affected by different background noise in real environment to reduce the speech intelligibility, in particular, for hearing impaired listeners. In order to improve the above issue, several hearing aids have been developed to enhance the speech signal in noisy environment. Most of current hearing aids were designed to enhance the component of speech and suppress the component of noise. However, it is difficult to separate other speech sources. Adaptive signal enhancement with the beamforming technique might improve the above issue. However, how to distinguish the location of the desired speaker effectively is still a difficult challenge for adaptive beamforming method. A novel concept of hearing aid was proposed in this study. Different from the beamforming-based hearing aids, which use the cross-correlation-coefficient method to estimate time difference of arrival (TDOA), an image recognition technology was used to estimate the location of the desired speaker to obtain the more precise TDOA. An adaptive signal enhancement was also used to enhance the noisy speech sound. From the experimental results, the proposed system could provide a smaller absolute error of TDOA less than 1.25 x 10(-4) ms, and a clear speech sound from the target speaker who the user wants to listen to.
Wireless surface electromyography monitoring system for dysphagia evaluation
(2014-01-01)
Cheng, Chih-Jen
;
Yang, Zu-Po
;
Ou, Chien-Zhi
;
Lin, Bor-Shyh
;
光電系統研究所
Swallowing difficulty is also called dysphagia. It is usually a sign related to the problems of your throat or esophagus the muscular tube that moves food and liquids from the back of your mouth to your stomach. These diseases are the common problem in people who have problems of the brain or nervous system. Surface electromyography (sEMG) signals provide the valuable information about the changes in the muscle when measuring and analyzing localized muscle fatigue. Several previous studies have reported swallowing behavior by sEMG. But there are no objective methods to assess swallowing coordination. In previous studies, the sEMG system was usually bulk, and it caused inconvenience to the users. So, this study proposed the wireless surface electromyography monitoring system for dysphagia evaluation. In order to assess the more accurate coordination of activities, the cross-correlation coefficient was used to determine the correlation between the sEMG of different muscle groups. The experimental results show that the discoordination indexes for dysphagia patients are obviously greater than that of healthy subjects.