• 한국음향학회지
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• 제24권2호
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• pp.68-77
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• 2005

입체음향 시스템의 목적은 청취자에게 음원을 획득한 장소에 있는 것과 같은 느낌을 주는 것이다. 이를 위해 일반적으로 더미헤드가 많이 사용되고 있다. 인간의 머리형태를 한 더미헤드의 특성 때문에 더미헤드를 통해 획득한 음원을 헤드폰을 통해 청취하는 경우 현장감을 느낄 수 있다. 하지만 더미헤드의 형태 및 크기는 공공장소에서 사용하기에는 제약이 있고 더미헤드를 통해 획득한 신호는 멀티채널로 확장하기가 어렵기 때문에 본 논문에서는 이러한 더미헤드를 구체로 간략화 한 후 구체 위에 다수 개의 마이크를 배치하여 입체음원을 획득하기 위한 멀티채널 3차원 마이크 기술에 대해 제안한다. 본 논문에서 제안하는 멀티채널 3차원 마이크는 구체 위의 수평면 상에 5개의 마이크를 배치하여 입체 음원을 획득한 다음 후처리 과정을 통해 헤드폰, 스테레오, 스테레오 다이폴, 4채널 및 5채널 재생환경 등에서 재생이 가능하다. 다양한 재생신호의 생성을 위한 후처리 과정은 많은 연산량을 필요로 하기 때문에, H/W로 제작하였다. 멀티채널 3차원 마이크의 성능을 검증하기 위해 방향성 실험을 수행한 결과, 멀티채널 재생환경에서 더미헤드 기술의 단점인 전/후방 혼동현상을 현저하게 줄일 수 있었다.

• ETRI Journal
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• 제27권2호
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• pp.153-165
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• 2005

The main purpose of a spatial audio system is to give a listener the same impression as if he/she were present in a recorded environment. A dummy head microphone is generally used for such purposes. Because of its human-like shape, we can obtain good spatial sound images. However, its shape is a restriction on its public use and it is difficult to convert a 2-channel recording into multi-channel signals for an efficient rendering over a multi-speaker arrangement. In order to solve the problems mentioned above, a spatial audio system is proposed that uses multiple microphones on a rigid sphere. The system has five microphones placed on special points of the rigid sphere, and it generates audio signals for headphone, stereo, stereo dipole, 4-channel, and 5-channel reproduction environments. Subjective localization experiments show that front/back confusion, which is a common limitation of spatial audio systems using the dummy head microphone, can be reduced dramatically in 4-channel and 5-channel reproduction environments and can be reduced slightly in a headphone reproduction.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵
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• pp.87-93
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• 1999

In this paper, we introduce a novel virtual studio environment where a broadcaster in the virtual set interacts with tele-viewers as if they are sharing the same environment as participants. A tele-viewer participates physically in the virtual studio environment by a dummy-head equipped with video "eyes" and microphone "ears" physically located in the studio. The dummy head as a surrogate of the tole-viewer follows the tele-viewer's head movements and views and hears through the dummy head like a tele-operated robot. By introducing the tele-presence technology in the virtual studio setting, the broadcaster can not only interact with the virtual set elements like the regular virtual studio environment but also share the physical studio with the surrogates of the tele-viewers as participants. The tele-viewer may see the real broadcaster in the virtual set environment and other participants as avatars in place of their respective dummy heads. With an immersive display like HMD, the tele-viewer may look around the studio and interact with other avatars. The new interactive virtual studio with the immersive viewer environment may be applied to immersive tele-conferencing, tele-teaching, and interactive TV program productions.program productions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.751-755
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• 2005

We propose a sound source localization method using the Head-Related-Transfer-Function (HRTF) to be implemented in a robot platform. In conventional localization methods, the location of a sound source is estimated from the time delays of wave fronts arriving in each microphone standing in an array formation in free-field. In case of a human head this corresponds to Interaural-Time-Delay (ITD) which is simply the time delay of incoming sound waves between the two ears. Although ITD is an excellent sound cue in stimulating a lateral perception on the horizontal plane, confusion is often raised when tracking the sound location from ITD alone because each sound source and its mirror image about the interaural axis share the same ITD. On the other hand, HRTFs associated with a dummy head microphone system or a robot platform with several microphones contain not only the information regarding proper time delays but also phase and magnitude distortions due to diffraction and scattering by the shading object such as the head and body of the platform. As a result, a set of HRTFs for any given platform provides a substantial amount of information as to the whereabouts of the source once proper analysis can be performed. In this study, we introduce new phase and magnitude criteria to be satisfied by a set of output signals from the microphones in order to find the sound source location in accordance with the HRTF database empirically obtained in an anechoic chamber with the given platform. The suggested method is verified through an experiment in a household environment and compared against the conventional method in performance.

• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1268-1278
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• 2004

Measurement of noise is not only to know the information of acoustic pressure but to assess human response to noise. To find human response to transportation noise through the laboratory study we have to measure and reproduce noise. The method of noise reproduction is largely divided into monaural and binaural techniques. But human fundamentally hears sound through both ears, referred as binaural hearing. Binaural signal is different from monaural signal because it includes more information of physical phenomena like acoustical reflection, diffraction and refraction. Especially head and pinna play an important role in perceiving change of signal origin. So, the amplitude of binaural signal is higher than that of monaural signal and spectrum of both signals is discriminated. Most of assessment and regulation of transportation noise are, however, based on monaural measurement techniques. The quantitative difference between monaural and binaural measurement is investigated in this study. Comparison on several transportation noisesshows defect of information in monaural measurements.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.109-114
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• 2004

Measurement of noise is not only to know the information of acoustic pressure but to assess human response for noise. Provided that want to find human response for transportation noise, we will have to reproduce the measured noise. The method of reproduction is largely divided into monaural and binaural reproduction techniques. Human fundamentally hears sound through both ears, which is binaural hearing. And binaural technique includes the more information of physical phenomena like acoustical reflection and deflection. So, binaural reproduction is more suitable for assessment of the psychoacoustical and physiological response for transportation noise exposures.