원형 머리 모델을 이용한 머리 전달 함수의 보간 (HRTF Interpolation Using a Spherical Head Model)

서지정보

· 발행기관 : 한국음향학회
· 수록지 정보 : 한국음향학회지 / 27권 / 7호 / 333 ~ 341페이지
· 저자명 : 이기승, 이석필

초록

본논문에서는머리전달함수에대한새로운보간기법을제안하였다.제안된기법은각방위각에대한머리전달함수의
충격파응답이인접방위각에대한시간지연된충격파응답의선형보간으로주어진다고가정하였다. 각방위각에대한
충격파응답의시간지연은방위각,머리의물리적형태,음원과머리의거리정보를이용하여추정될수있는귀와음원간의
전파시간과최소자승오차를갖도록하는교정값의합으로주어진다. 또한제안된모델에서는보간시방위각의간격을
고정 간격이 아닌 가변 간격으로 하였으며 본래의 충격파 응답과 보간된 충격파 응답이 본래의 충격파 응답과 비교하여
청취상으로큰차이가느껴지지않고, 보간에필요한충격파응답의개수가최소화되는조건을만족하도록결정하였다.
제안된 보간 모델의 유용성을 검증하기 위하여 더미 헤드 및 3명의 사람으로부터 측정된 머리 전달 함수에 대해 제안된
보간모델을적용하였다.머리전달함수는0도의고도각을갖는수평면을5도간격의방위각으로분할한총72개가사용되
었으며, 실험 결과 전체 머리 전달 함수 중 단지 30~40% 만을 사용하고 나머지는 보간에 의해 얻어진 머리전달 함수를
사용하더라도 청취상의 음원의 위치가 변동되지 않음을 알 수 있었다.

영어초록

In this paper, a new interpolation model for the head related transfer function (HRTF) was proposed. In the method
herein, we assume that the impulse response of the HRTF for each azimuth angle is given by linear interpolation
of the time-delayed neighboring impulse responses of HRTFs. The time delay of the HRTF for each azimuth angle
is given by sum of the sound wave propagation time from the ears to the sound source, which can be estimated
by using azimuth angle, the physical shape of the underlying head and the distance between the head and sound
source, and the refinement time yielding the minimum mean square error. Moreover, in the proposed model, the
interpolation intervals were not fixed but varied, which were determined by minimizing the total number of HRTFs
while the synthesized signals have no perceptual difference from the original signals in terms of sound location.
To validate the usefulness of the proposed interpolation model, the proposed model was applied to the several HRTFs
that were obtained from one dummy-head and three human heads. We used the HRTFs that have 5 degree azimuth
angle resolution at 0 degree elevation (horizontal plane). The experimental results showed that using only 30~50%
of the original HRTFs were sufficient for producing the signals that have no audible differences from the original
ones in terms of sound location.

참고자료

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