Time-difference of arrival model for spherical microphone arrays and application to direction of arrival estimation. Nikunen, J. & Virtanen, T. In 2017 25th European Signal Processing Conference (EUSIPCO), pages 1255-1259, Aug, 2017.
Time-difference of arrival model for spherical microphone arrays and application to direction of arrival estimation [pdf]Paper  doi  abstract   bibtex   
This paper investigates different steering techniques for spherical microphone arrays and proposes a time-difference of arrival (TDOA) model for microphones on surface of a rigid sphere. The model is based on geometric interpretation of wavefront incident angle and the extra distance the wavefront needs to travel to reach microphones on the opposite side of a sphere. We evaluate the proposed model by comparing analytic TDOAs to measured TDOAs extracted from impulse responses (IR) of a rigid sphere (r = 7.5cm). The proposed method achieves over 40% relative improvement in TDOA accuracy in comparison to free-field propagation and TDOAs extracted from analytic IRs of a spherical microphone array provide an additional 10% improvement. We test the proposed model for the application of source direction of arrival (DOA) estimation using steered response power (SRP) with real reverberant recordings of moving speech sources. All tested methods perform equally well in noise-free scenario, while the proposed model and simulated IRs improve over free-field assumption in low SNR conditions. The proposed model has the benefit of only using single delay for steering the array.
@InProceedings{8081409,
  author = {J. Nikunen and T. Virtanen},
  booktitle = {2017 25th European Signal Processing Conference (EUSIPCO)},
  title = {Time-difference of arrival model for spherical microphone arrays and application to direction of arrival estimation},
  year = {2017},
  pages = {1255-1259},
  abstract = {This paper investigates different steering techniques for spherical microphone arrays and proposes a time-difference of arrival (TDOA) model for microphones on surface of a rigid sphere. The model is based on geometric interpretation of wavefront incident angle and the extra distance the wavefront needs to travel to reach microphones on the opposite side of a sphere. We evaluate the proposed model by comparing analytic TDOAs to measured TDOAs extracted from impulse responses (IR) of a rigid sphere (r = 7.5cm). The proposed method achieves over 40% relative improvement in TDOA accuracy in comparison to free-field propagation and TDOAs extracted from analytic IRs of a spherical microphone array provide an additional 10% improvement. We test the proposed model for the application of source direction of arrival (DOA) estimation using steered response power (SRP) with real reverberant recordings of moving speech sources. All tested methods perform equally well in noise-free scenario, while the proposed model and simulated IRs improve over free-field assumption in low SNR conditions. The proposed model has the benefit of only using single delay for steering the array.},
  keywords = {direction-of-arrival estimation;microphone arrays;reverberation;time-of-arrival estimation;transient response;spherical microphone array;rigid sphere;wavefront incident angle;TDOA accuracy;direction of arrival estimation;time-difference of arrival model;steering techniques;impulse responses;steered response power;reverberant recordings;moving speech sources;size 7.5 cm;Microphone arrays;Direction-of-arrival estimation;Surface waves;Estimation;Surface treatment},
  doi = {10.23919/EUSIPCO.2017.8081409},
  issn = {2076-1465},
  month = {Aug},
  url = {https://www.eurasip.org/proceedings/eusipco/eusipco2017/papers/1570346912.pdf},
}
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