• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.334-337
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• 2003

입체음향을 구현하는 방법에는 5 혹은 6 개의 스피커를 사용하는 5.1 채널 음향재생 시스템과 2개의 스피커를 사용하는 방법있다. 2 채널 입체음향재생 시스템은 라우드 스피커 재생보다 헤드폰 재생에 사용되고 있다. 2 채널로 입체음향을 재생하기 위하여 사람의 머리와 귀바퀴를 FIR 필터로 모델링한 머리전달함수(HRTF, head related transfer function)을 이용한다. FIR 필터로 측정된 HRTF는 실시간 처리에 있어서 계산량이 많은 단점이 있다. 본 논문에서는 2 채널 입체 음향시스템을 효과적으로 구현하기 위하여 FIR HRTF를 HR필터로 구현하는 방법을 제안한다. FIR 필터계수로부터 IIR 필터계수를 구하는 알고리즘은 균형화 모델 감소법(balanced model reduction)을 이용한다. 본 논문에서는 IIR 필터로 차수를 줄인 HRTF로 입체음향을 재생하는 시뮬레이션을 하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.841-848
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• 2008

Based on the averaged Korean head shapes that are the results of digital Korean project by KISTI and Catholic university, experimental apparatus of head dummies of Korean male and female are developed in order to measure head-related transfer functions(HRTF) by using a reverse engineering and rapid prototyping techniques. For the Korean dummies, HRTFs are measured using the substitution method ever 12kHz frequency bands. At every azimuth angle $15^{\circ}$ HRTFs are measured for elevation angles $-30^{\circ}$, $0^{\circ}$ and $-30^{\circ}$. The measured HRTFs are compared with those of KEMAR(knowles electronic manikin for acoustic research) dummy head, which shows $3{\sim}5\;dB$ difference over $4{\sim}5\;kHz$ kHz frequency band.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.669-673
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• 2008

Based on the averaged Korean head shapes that are the results of digital Korean project by KISTI and Catholic university, experimental apparatus of head dummies of Korean male and female are developed in order to measure head-related transfer functions (HRTF) by using a reverse engineering and rapid prototyping techniques. For the Korean dummies, HRTFs are measured using the substitution method over 12 kHz frequency bands. At every azimuth angle $15^{\circ}$ HRTFs are measured for elevation angles $-30^{\circ}$, $0^{\circ}$, and $30^{\circ}$. The measured HRTFs are compared with those of KEMAR (Knowles Electronic Manikin for Acoustic Research) dummy head, which shows a little different frequency characteristic beyond 2 kHz frequency band.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1009-1013
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• 2007

To do a HRTF customization, researchers used a spherical head model for modeling the head block of structural modeling of HRTF, which is the one of the technique for HRTF customization, because of its simplicity. In this paper, an analytic spheroidal HRTF caused by an incident point source will be introduced. Using proposed spheroidal HRTF, near-field HRTF customization can be applicable through a structural modeling of HRTF. To see the necessity of sheroidal head model, comparison of two analytic solutions, which are classical spherical HRTF and proposed spheroidal HRTF, will be shown. On the view point of ITD, optimal head model which matches with the measured ITD of KEMAR HRTF can be obtained. ITD results show that there are only slight differences between spherical and spheroidal head model. Magnitude comparison is made by constructing head model using measured head size. Although magnitude comparison is not studied between optimal models, the results of 24 of 36 subjects are shown that spheroidal head model matches notch frequency pattern of measured HRTF better than those of spherical one, where the sound source is at contralateral position.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.297-298
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• 2010

임의의 위치에 음상을 정위하는 방법으로, 머리전달함수(HRTF : Head Related Transfer Function)을 원음에 convolution 하는 기법이 사용된다. 하지만 더미헤드를 이용하여, 각각의 고도각과 방위각에서 측정된 HRTF는 사용자에 따라 정위감을 저하시킬 수 있다. 또한 좌표로 표현되는 영상과는 달리, 소리는 들려오는 방향을 정확한 좌표로 표현하기가 힘들다. 이에 본 논문은 비개인화된 HRTF를 사용하여 음상을 정위하는 경우의 정위감 개선에 대한 방법을 제안한다. 정위감 개선을 위해 음상을 정위하려는 위치 주변의 HRTF를 그룹화하는 방법에 대해 연구하였으며, 그룹화된 HRTF를 이용하여 정위한 음상의 청감평가를 수행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.572-574
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• 2014

Researches on three-dimensional multimedia has been performed actively in recent years. Virtual sound technology corresponding to virtual image should be provided to implement 3D multimedia with high quality. Head-related transfer function (HRTF) plays a key role in this research area. HRTFs measured in changing azimuth, elevation, and distance for each and every subject is necessary for ideal solution. However, it is practically impossible to measure all subjects' HRTFs, so various HRTF databases have been built by many researchers. Because HRTF displays quite different aspects from subject to subject, HRTF of dummy head has been used for generic usage. However, mannequin's HRTF showed much worse performance comparing with individual case so this solution should be improved. From previous work, standardization of HRTF based on tensor-singular value decomposition method has been proposed. For effective extraction of standard HRTF, three different decomposition methods are compared in this paper.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.04a
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• pp.201-205
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• 1998

시스템공학연구소 감성공학연구부에서는 수행중인 "멀티미디어 컨텐트용 입체음향처리 S/W개발"과제의 일환으로 머리전달함수(Head-Related Transfer Function, HRTF)의 측정을 수행하였다. 본 논문에서는 무향실에서의 HRTF 데이터 측정 과정 및 얻어진 HRTF들에 대한 음상정위청취 평가 결과에 대해 설명한다. 청취 평가에서는 피험자들이 측정된 HRTF와 MIT Media Lab의 KEMAR 더미헤드 HRTF를 사용하여 각 방향에 대해 필터링된 음원을 듣고 음상정위 주관평가를 시행하였는에, 측정된 HRTF를 사용하여 양호한 음상정위 결과를 얻을 수 있음을 확인하였다.있음을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.616-619
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• 2005

An extensive data base of HRTFs (Head Related Transfer Functions) has been established in order to work with high qualifies of 3D acoustic appliances. The basic specifications of the measurement presented are that a spatial resolution of 10$^{\circ}$ in elevation angles (ranging from -40$^{\circ}$ to 90$^{\circ}$) and uniform spatial resolution of 5$^{\circ}$ in azimuth angles. The distance from the measurement sources to the centre of the dummy head is 2m and the sampling frequency is 48 kHz and the quantisation depth is 24-bits. The data is presented for three arrangements of pinna models (large, small and no pinna) which were combined with the open and blocked ear canal cases to give a total of 6 sets of measurements. The data base may contribute to show promise of providing useful applications of 3D sound.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.706-707
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• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.338-339
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• 2009