• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.85-88
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• 1998

심리음향학적으로 소리의 감성 요소를 평가하려는 시도가 계속되고 있으나 뚜렷한 결과가 나온 것은 많지 않다. 또한 감성 인자 평가에 대한 국제적인 표준도 정확히 나와있지 않다. 일반적으로 심리음향학 인자로 loudness, sharpness, roughness, fluctuation strength, pleasantness, annoyance를 사용하며, 이러한 인자들을 이용하여 바이노럴 음질 평가 시스템을 구현하였다. 구현된 바이노럴 음질 평가 시스템의 객관성을 평가하기 위해 인성 실험을 실시하였고 인성 실험 결과와 음질 평가 시스템을 이용한 평가 결과를 비교 분석하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.219-222
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• 2000

입체음향 생성을 위한 기존의 방법은 크게 바이노럴 녹음기법과 머리전달함수(HRTF)를 이용한 바이노럴 합성 기법으로 크게 나눌 수 있다. 바이노럴 기법으로 생성된 이러한 입체음향은 재생을 위해 역 필터와 Equalization 곡선을 선택하게 되는데 이것은 음질에 중요한 영향을 주게 된다 본 논문은 재생시 음질의 향상을 위해 적합한 역 필터 설계와 Equalization 곡선의 선택방법을 제시하고 트랜스오럴 시스템 설계 시 신호처리로 인한 음질의 저하를 최소화하기 위해 스피커의 위치를 청취자의 머리 뒤에 놓는 방법을 제안하고자 한다. 그리고 청취자의 정면에 스피커를 한 개 추가하여 정면의 음상을 강화하고 3 채널 바이노럴 녹음기법(1)으로 만들어진 음원에 대한 호환성을 갖게 한다. 마지막으로 이 제안된 모든 방법들을 실시간으로 재생하는 시스템을 구현한다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.215-218
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• 2000

입체음향 생성을 위한 기존의 방법은 크게 바이노럴 녹음기법과 머리전달함수(HRTF)를 이용한 바이노럴 합성 기법으로 나눌 수 있다. 현재 바이노럴 기법은 기존 스테레오 시스템에 비해 공간감, 몰입감 측면에서는 탁월한 효과가 있지만, 음질의 저하와 정면 음상 정위가 잘되지 않는다는 치명적인 단점 때문에 프로페셔널 오디오 분야에서는 거의 사용되지 않고 몇몇 PC 게임용으로만 사용되고 있다. 본 논문은 정확한 정면 음상 정위를 위해 '3채널 더미헤드를 이용한 바이노럴 녹음기법' 을 제안하고, 기존 스테레오 녹음기법과의 호환성 유지를 위해 녹음 현장에서 직접 사용될 수 있는 3채널 더미헤드를 사용한 'Weighted Diffuse-field equalization 기법'에 대해 제안하며, 3 채널 더미헤드를 이용하여 기존 HRTF 데이터를 대체할 수 있는 정면 음상 정위에 강인한 '3 채널 더미헤드 HRTF 측정 기법'에 대해 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.527-528
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• 2016

In this paper, to provide a binaural beat in the method of treatment of sleep disorders. Let the sound of different frequencies, the waveform of the brain resonate at a specific frequency, to induce a stable state, is converted over to a high-frequency audio frequency, improves the listening experience. To target the three college students for the results performance evaluation of, conducted an experiment on the sense of stability at the time of sleep, in the process, the brain waves were measured as a means to check the degree of sense of stability.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.283-286
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• 1998

monaural 신호는 귀의 특성과 인간의 청취 특성을 정확하게 반영하지 못하는 문제점이 있다. 귀 자체의 특성이 binaural인 것을 생각하면 monaural 신호를 이용한 방법은 정확한 결과가 나오기 어렵다. 따라서 이 논문에서는 monaural 신호를 이용한 음질 평가 시스템의 단점을 보완하고 귀의 binaural 특성을 살린 binaural 음질 평가 시스템을 구현하였다. 소리에 대한 심리음향학 인자로는 monaural 평가에서 사용했던 loudness, sharpness, roughness, fluctuation strength, annoyance, pleasantness를 binaural에 맞도록 수정하였으며, monaural 평가에서는 사용하지 않았던 tonality를 추가하여 pleasantness의 annoyance의 계산식을 수정하였다.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1421-1431
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• 2005

There are two methods in 3-D sound reproduction: a surround system, like 3.1 channel method and a binaural system using 2-channel method. The binaural system utilizes the sound localization principle of a human using two ears. Generally, a crosstalk between each channel of 2-channel loudspeaker system should be canceled to produce a natural 3-D sound. To solve this problem, it is necessary to trace a head movement. In this paper, we propose a new algorithm to correctly trace the head movement of a listener. The Proposed algorithm is based on the detection of face and eye. The face detection uses the intensity of an image and the position of eyes is detected by a mathematical morphology. When the head of the listener moves, length of borderline between face area and eyes may change. We use this information to the tracking of head movement. A computer simulation results show That head movement is effectively estimated within +10 margin of error using the proposed algorithm.

• The Journal of the Acoustical Society of Korea
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• v.27 no.4
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• pp.207-214
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• 2008

To create 3D sound, we usually use two methods which are two channels or multichannel sound systems. Because of cost and space problems, we prefer two channel sound system to multi-channel. Using a headphone or two speakers, the most typical method to create 3D sound effects is a technology of head related transfer function (HRTF) which contains the information that sound arrives from a sound source to the ears of the listener. But it causes a problem to localize a sound source around a certain places which is called cone-of-confusion. In this paper, we proposed the new algorithm to reduce the confusion of sound image localization. HRTF grouping and psychoacoustics theory are used to boost the spectral cue with spectrum difference among each directions. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than conventional methods.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.381-386
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• 2008

Virtual 3D audio methods that create 3D sound effects are researched highly for multimedia devices using 2 speakers or headphone. The most typical method to create 3D effects is a technology through use of head related transfer function (HRTF) which contains the information that sound arrives from a sound source to the ears of the listener. But it can decline some 3D effects by cone of confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that creates realistic 3D audio. In order to improve 3D sound, we calculate the excitation energy of each symmetric HRTF and extract the ratio of energy of each bark range. Informal listening tests show that the proposed method improves the front-bach sound localization characteristics much better than the conventional methods.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.1
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• pp.71-77
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• 2005

In this paper we implement a headphone-based 5.1 channel 3-dimensional (3D) sound generation system using HRTF (Head Related Transfer Function). Each mono sound source in the 5.1 channel signal is localized on its virtual location by binaural filtering with corresponding HRTFs, and reverberation effect is added for spatialization. To reduce the computational burden, we reduce the number of taps in the HRTF impulse response and model the early reverberation effect with several tens of impulses extracted from the whole impulse sequences. We modified the spectrum of HRTF by weighing the difference of front-back spec01m to reduce the front-back confusion caused by non-individualized HRTF DB. In informal listening test we can confirm that the implemented 3D sound system generates live and rich 3D sound compared with simple stereo or 2 channel down mixing.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.74-86
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• 2005

In this paper, we proposed an algorithm for the approximation of high order FIR filters by low order IIR filters to efficient implementing two channel 3-D surround sound systems using Head-related transfer functions(HRTFs). The algorithm is based on a concept of the balanced model reduction. The binaural sounds using the approximated HRTFs are reproduced by headphone, and serves as a cue of sound image localization. HRTFs of dummy-head are approximated from 512-order FIR filters by 32-order IIR filters and compare with each other. .Experiment of sound image are carried out for 10 participants. We perform the experiment based on computer simulation and hardware experiment with TMS320C32. The results of the experiments show that the localization using the approximated HRTFs is the same accuracy as the case of FIR filters that simulate the HRTFs.