• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1997년도 추계학술대회
• /
• pp.79-82
• /
• 1997

In this paper, a body-worn type digital hearing aid (DHA) based on a dedicated DSP chip is developed. A fitting software running on a PC supported by the Win95 OS is also developed. The fitting protocol is based on the NAL-R procedure applied to eight frequency bands, but it is designed to support a curvilinear fitting to cope with the nonlinear perception of hearing-impaired listeners. Preliminary subjective tests regarding the speech intelligibility and perceived quality revealed that the new DHA could be of benefit to hearing aid users.

• 한국음향학회지
• /
• 제19권8호
• /
• pp.12-21
• /
• 2000

본 논문에서는 심리음향 (psychoacoustics)을 이용한 다채널 동적 음향 압축 알고리즘을 통해 감음신경성 난청 (sensorinural hearing loss)을 보정하여 정상적인 지각 환경을 제공하는 알고리즘을 제안한다. 제안된 알고리즘은 라우드니스 조정 함수 (loudness scaling function)를 통해 난청자에게 적합한 라우드니스 레벨을 보상 시켜 주고, 난청자가 인식하게 되는 신호에 대한 마스킹 특성을 해석하여, 지각 영역 (perceptual domain)에서 각각의 주파수 성분에 대한 음압 레벨과 마스킹 임계치 (masking threshold) 사이의 거리로 정의되어지는 SMR(signal-to-masking ratio)을 통해 주파수 대비 (spectral contrast)를 복원 시켜 줌으로써 정상적인 지각 환경을 제공하는 것이다.

• 한국정보전자통신기술학회논문지
• /
• 제10권1호
• /
• pp.102-110
• /
• 2017

본 논문에서는 다채널 디지털 보청기에 적용 가능한 적응 음향 궤환 제거(Adaptive Feedback Cancellation : AFC) 알고리즘을 실시간으로 구현한다. 다채널 디지털 보청기는 일반적으로 난청 보상을 위해 FFT 필터뱅크 기반 광역 동범위압축(Wide Dynamic Range Compression) 알고리즘을 사용한다. 구현한 실시간 음향 궤환 제거 알고리즘은 다채널 디지털 보청기와 동일한 FFT 필터뱅크를 사용하여 WDRC와 함께 하나의 통합된 구조를 가짐으로써 보청기 배터리 수명에 영향을 미치는 연산량 측면에서 이득을 볼 수 있었다. 구현된 음향 궤환 제거 알고리즘은 고정 및 변화하는 음향 궤환 경로를 실시간으로 추정하여 보청기 출력 신호의 품질을 향상시킴을 확인하였다. 또한 비선형적인 입, 출력에 의해 음향 궤환 제거기가 정상적으로 작동하지 못해 출력 신호의 포화가 일어날 경우 감소 이득을 적용하여 시스템의 안정성을 높이고자 하였다. 결과적으로 다양한 실제 사용 환경에서 강건하게 동작하는 알고리즘을 구현할 수 있었다. 본 알고리즘은 추후 음질 개선 알고리즘 등 다양한 기능의 추가 구현이 용이하다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 학술대회지
• /
• pp.755-758
• /
• 2004

A hearing aid performs the role of fitting in order to provide those with a hearing problem with a better hearing ability in ordinary circumstances. The existing Fitting system in the hearing aid is consisted somewhat complex, and simply performs the role of Fitting without any supervisions of those with a hearing problem. Such is these methods makes it unable to establish an organized supervision, and shows a problem in making high efficiency. In order to solve this problem mentioned as above, the based thesis have connected the Fitting program and the patient-management database program for the easy use by the user.

• 한국음향학회지
• /
• 제36권2호
• /
• pp.123-129
• /
• 2017

본 논문은 보청기의 지향성 알고리즘을 실시간으로 실현한 내용을 다루었다. 기존의 시간 영역에서의 시간 지연 기법에 의한 지향성 실현을 디지털 필터 방식으로 처리함으로써 시간 지연 적용이 불가능한 일반 DSP(Digital Signal Processing) 칩으로도 유사한 지향성 패턴을 가능하게 하였다. 시간 지연 기법과 디지털 필터 기법을 각각 Matlab(Matrix laboratory) 기반으로 비교 검증한 후에, 이를 CSR 8675 블루투스 DSP IC(Digital Signal Processing Integrated Circuit) 칩 펌웨어로 실현하고 검증해보였다. 스마트폰으로의 원격 무선 제어 기능으로 스마트 자향성 보청기의 사용자 접근 편의성을 강화시켰다.

• 대한의용생체공학회:의공학회지
• /
• 제34권1호
• /
• pp.8-13
• /
• 2013

Persons with sensorineural hearing impairment have troubles in hearing at noisy environments because of their deteriorated hearing levels and low-spectral resolution of the auditory system and therefore, they use hearing aids to compensate weakened hearing abilities. Various algorithms for hearing loss compensation and environmental noise reduction have been implemented in the hearing aid; however, the performance of these algorithms vary in accordance with external sound situations and therefore, it is important to tune the operation of the hearing aid appropriately in accordance with a wide variety of sound situations. In this study, a sound classification algorithm that can be applied to the hearing aid was suggested. The proposed algorithm can classify the different types of speech situations into four categories: 1) speech-only, 2) noise-only, 3) speech-in-noise, and 4) music-only. The proposed classification algorithm consists of two sub-parts: a feature extractor and a speech situation classifier. The former extracts seven characteristic features - short time energy and zero crossing rate in the time domain; spectral centroid, spectral flux and spectral roll-off in the frequency domain; mel frequency cepstral coefficients and power values of mel bands - from the recent input signals of two microphones, and the latter classifies the current speech situation. The experimental results showed that the proposed algorithm could classify the kinds of speech situations with an accuracy of over 94.4%. Based on these results, we believe that the proposed algorithm can be applied to the hearing aid to improve speech intelligibility in noisy environments.

• 재활복지공학회논문지
• /
• 제7권1호
• /
• pp.67-72
• /
• 2013

청각장애인 근로자를 대상으로 보청기 사용유무에 따른 직무만족도와 일상생활만족도 차이를 알아보기 위해 장애인고용패널조사(Panel Survey of Employment for the Disabled) 4차년도 자료에서 근로자 187명을 대상으로 분석하였다. 분석결과 보청기 사용 유무에 따라 직무만족도와 일상생활만족도 모두 유의미한 차이를 보이지 않는 것으로 나타났으며, 보청기사용 청각장애인의 직무만족도는 일상생활만족도에 긍정적인 역할을 하는 것으로 나타났다. 이러한 결과는 청각장애인에게 보청기는 중요한 역할을 하는 보조기구이지만, 본 연구에서 사용한 패널자료의 특성상 정보화기기 사용증가와 의사소통지원서비스 확대에 따른 영향요인을 반영하지 못한 결과라고 생각된다. 이러한 내용을 바탕으로 연구의 제한점과 함의를 결론에서 제시하였다.

• Journal of Audiology & Otology
• /
• 제25권3호
• /
• pp.146-151
• /
• 2021

Background and Objectives: The relationship between hearing aid (HA) use and improvement in cognitive function is not fully known. This study aimed to determine whether HAs could recover temporal resolution or hearing in noise functions. Materials and Methods: We designed a prospective study with two groups: HA users and controls. Patients older than 45 years, with a pure tone average threshold of worse than 40 dB and a speech discrimination score better than 60% in both ears were eligible. Central auditory processing tests and hearing in noise tests (HINTs) were evaluated at the beginning of the study and 1, 3, 6, and 12 months after the use of a monaural HA in the HA group compared to the control group. The changes in the evaluation parameters were statistically analyzed using the linear mixed model. Results: A total of 26 participants (13 in the HA and 13 in the control group) were included in this study. The frequency (p<0.01) and duration test (p=0.02) scores showed significant improvements in the HA group after 1 year, while the HINT scores showed no significant change. Conclusions: After using an HA for one year, patients performed better on temporal resolution tests. No improvement was documented with regard to hearing in noise.

• 대한청각학회지
• /
• 제25권2호
• /
• pp.72-79
• /
• 2021

Background and Objectives: The speech-in-noise test is typically performed using an audiometer. The results of the digit-in-noise recognition (DIN) test may be influenced by the flat frequency response of free-field audiometry and frequency of the hearing aid fit based on fitting rationale. This study aims to investigate the DIN test in unaided and aided conditions. Subjects and Methods: Thirty four adults with moderate and severe sensorineural hearing loss (SNHL) participated in the study. The signal-to-noise ratio (SNR) for 50% of the DIN test was obtained in the following two conditions: 1) the unaided condition, performed using an audiometer in a free field; and 2) aided condition, performed using a hearing aid with an unvented individual earmold that was fitted based on NAL-NL2. Results: There was a statistically significant elevation in the mean SNR for the severe SNHL group in both test conditions when compared with that of the moderate SNHL group. In both groups, the SNR for the aided condition was significantly lower than that of the unaided condition. Conclusions: Speech recognition in hearing-impaired patients can be realized by fitting hearing aids based on evidence-based fitting rationale rather than by measuring it using free-field audiometry measurement that is utilized in a routine clinic setup.

• 대한청각학회지
• /
• 제25권3호
• /
• pp.146-151
• /
• 2021

Background and Objectives: The relationship between hearing aid (HA) use and improvement in cognitive function is not fully known. This study aimed to determine whether HAs could recover temporal resolution or hearing in noise functions. Materials and Methods: We designed a prospective study with two groups: HA users and controls. Patients older than 45 years, with a pure tone average threshold of worse than 40 dB and a speech discrimination score better than 60% in both ears were eligible. Central auditory processing tests and hearing in noise tests (HINTs) were evaluated at the beginning of the study and 1, 3, 6, and 12 months after the use of a monaural HA in the HA group compared to the control group. The changes in the evaluation parameters were statistically analyzed using the linear mixed model. Results: A total of 26 participants (13 in the HA and 13 in the control group) were included in this study. The frequency (p<0.01) and duration test (p=0.02) scores showed significant improvements in the HA group after 1 year, while the HINT scores showed no significant change. Conclusions: After using an HA for one year, patients performed better on temporal resolution tests. No improvement was documented with regard to hearing in noise.