DOI QR코드

DOI QR Code

소형 마이크로폰 배열에 적용 가능한 음원 위치 추정법 비교

Comparison of the sound source localization methods appropriate for a compact microphone array

  • 정인지 (한국과학기술원 기계공학과) ;
  • 이정권 (한국과학기술원 기계공학과)
  • 투고 : 2019.10.28
  • 심사 : 2019.12.30
  • 발행 : 2020.01.31

초록

음원위치추정 기술은 사물인터넷 시대에서 다양한 응용 분야를 가지고 있으며, 이로 인해 마이크로폰 프로브의 크기가 중요하게 고려되고 있다. 음향 인텐시티 벡터를 이용한 음원위치추정 방법은 마이크로폰 사이의 간격이 좁을수록 유한차분오차가 작기 때문에 배열을 소형화 할 수 있다는 장점이 있다. 본 논문에서는 음향 인텐시티 벡터 및 도달시간차 방법을 통해 원거리 음장에서 음원의 위치 추정 시 발생하는 오차를 비교한다. 정사면체 형태의 3차원 마이크로폰 배열을 통해 마이크로폰 사이의 간격 변화에 따라서 오차를 비교하였다. 실제 환경에서 음원위치추정 방법의 유효성을 검증하기 위해 잔향음장 내에서 잔향시간을 변화시켜 추가 실험을 수행하였다. 도달시간차를 계산하기 위해 Generalized Cross Correlation-Phase transform(GCC-PHAT) 알고리즘을 적용하였다. 실험 결과, T60 = 0.4 s일 때 음향인텐시티법에 의한 위치추정 오차는 2.9°, 그리고 GCC-PHAT를 적용했을 때는 7.3° 이며, T60 = 1.0 s일 때 오차는 각각 9.9°, 13.0°이다. 이를 통해 일반 잔향장이 고려되는 실제 환경에서도 소형의 마이크로폰 배열을 통한 음향 인텐시티법은 음원의 위치를 추정하는데 유효하게 적용될 수 있음을 알 수 있다.

The sound source localization technique has various application fields in the era of internet-of-things, for which the probe size becomes critical. The localization methods using the acoustic intensity vector has an advantage of downsizing the layout of the array owing to a small finite-difference error for the short distance between adjacent microphones. In this paper, the acoustic intensity vector and the Time Difference of Arrival (TDoA) method are compared in the viewpoint of the localization error in the far-field. The comparison is made according to the change of spacing between adjacent microphones of the three-dimensional microphone array arranged in a tetrahedral shape. An additional test is conducted in the reverberant field by varying the reverberation time to verify the effectiveness of the methods applied to the actual environments. For estimating the TDoA, the Generalized Cross Correlation-Phase transform (GCC-PHAT) algorithm is adopted in the computation. It is found that the mean localization error of the acoustic intensimetry is 2.9° and that of the GCC-PHAT is 7.3° for T60 = 0.4 s, while the error increases as 9.9°, 13.0° for T60 = 1.0 s, respectively. The data supports that a compact array employing the acoustic intensimetry can localize of the sound source in the actual environment with the moderate reflection conditions.

키워드

참고문헌

  1. E. G. Williams, Fourier Acoustics (Academic Press, San Diego, 1999). Chap. 3.
  2. M. R. Bai, J. -G. Ih, and J. Benesty, Acoustic Array Systems: Theory, Implementation, and Application (John Wiley & Sons, Singapore, 2013). Chap. 5.
  3. C. Knapp and G. Carter, "The generalized correlation method for estimation of time delay," IEEE Trans. Acoust. Speech, and Signal Process. 24, 320-327 (1976). https://doi.org/10.1109/TASSP.1976.1162830
  4. L. Chen, Y. Liu, F. Kong, and N. He, "Acoustic source localization based on generalized cross correlation time-delay estimation," Procedia Eng. 15, 4912-4919 (2011). https://doi.org/10.1016/j.proeng.2011.08.915
  5. O. L. Frost, "An algorithm for linearly constrained adaptive array processing," Proc. IEEE. 60, 926-935 (1972). https://doi.org/10.1109/PROC.1972.8817
  6. J. Hald and J. J. Christensen, "A novel beamformer array design for noise source location from intermediate measurement distances," J. Acoust. Soc. Am. 112, 2448 (2002).
  7. R. Schmidt, "Multiple emitter location and signal parameter estimation," IEEE Trans. Antennas and Propagation, 34, 276-280 (1986). https://doi.org/10.1109/TAP.1986.1143830
  8. S. Miron, N. le Bihan, and J. I. Mars, "Quaternion-MUSIC for vector-sensor array processing," IEEE Trans. Signal Process. 54, 1218-1229 (2006). https://doi.org/10.1109/TSP.2006.870630
  9. B. V. D. Broeck, A. Bertrand, P. Karsmakers, B. Vanrumste, H. V. hamme, and M. Moonen, "Time-domain generalized cross correlation phase transform sound source localization for small microphone arrays," IEEE Education and Res. Conf. 76-80 (2012).
  10. G. Pavic, "Measurement of sound intensity," J. Sound Vib. 51, 533-545 (1977). https://doi.org/10.1016/S0022-460X(77)80050-3
  11. J. K. Thompson and D. R. Tree, "Finite difference approximation errors in acoustic intensity measurements," J. Sound Vib. 75, 229-238 (1981). https://doi.org/10.1016/0022-460X(81)90341-2
  12. F. J. Fahy, Sound Intensity (CRC Press, New York, 1995). Chaps. 4-6.
  13. S. -K. Cho and J. -G. Ih, "Source localization by uisng compact intensity array," Proc. KSNVE. 281-282 (2012).
  14. E. B. Whiting, J. S. Lawrence, K. L. Gee, T. B. Neilsen, and S. D. Sommerfeldt, "Bias error analysis for phase and amplitude gradient estimation of acoustic intensity and specific acoustic impedance," J. Acoust. Soc. Am. 142, 2208 (2017). https://doi.org/10.1121/1.5007834
  15. I. -J. Jung, J. -H. Woo, and J. -G. Ih, "Analysis of spectral fluctuation in the localization by using sound intensity" (in Korean), J. Acoust. Soc. Kr. Suppl.2(s) 34, 188 (2015).
  16. I. -J. Jung and J. -G. Ih, "Compensation of inherent bias errors in using the three-dimensional acoustic intensimetry for sound source localization," J. Sound Vib. 461, 114918 (2019). https://doi.org/10.1016/j.jsv.2019.114918
  17. J. -H. Woo, I. -J. Jung, S. -K. Cho, and J. -G. Ih, "Precision enhancement in source localization using a double-module, three-dimensional acoustic intensity probe," Appl. Acoust. 151, 63-72 (2019). https://doi.org/10.1016/j.apacoust.2019.03.009
  18. I. -J. Jung and J. -G. Ih, "Double tetrahedral intensity probes for reducing the spatial bias error of source localization," Proc. ICA. 23, 4957-4960 (2019).
  19. G. W. Elko, "Frequency domain estimation of the complex acoustic intensity and acoustic energy density," J. Acoust. Soc. Am. 77, 2194 (1985). https://doi.org/10.1121/1.391749
  20. J. C. Pascal and J. F. Li, "A systematic method to obtain 3D finite-difference formulations for acoustic intensity and other energy quantities," J. Sound Vib. 310, 1093-1111 (2008). https://doi.org/10.1016/j.jsv.2007.08.029
  21. E. A. Lehmann and A. M. Johansson, "Prediction of energy decay in room impulse responses," J. Acoust. Soc. Am. 124, 269-277 (2008). https://doi.org/10.1121/1.2936367