Prepeliță Sebastian, Geronazzo Michele, Avanzini Federico, Savioja Lauri
Department of Computer Science, Aalto University, Otaniementie 17, FI-02150, Espoo, Finland.
Department of Information Engineering, University of Padova, Via G. Gradenigo 6/A, 35131, Padova, Italy.
J Acoust Soc Am. 2016 May;139(5):2489. doi: 10.1121/1.4947546.
The scattering around the human pinna that is captured by the Head-Related Transfer Functions (HRTFs) is a complex problem that creates uncertainties in both acoustical measurements and simulations. Within the simulation framework of Finite Difference Time Domain (FDTD) with axis-aligned staircase boundaries resulting from a voxelization process, the voxelization-based uncertainty propagating in the HRTF-captured sound field is quantified for one solid and two surface voxelization algorithms. Simulated results utilizing a laser-scanned mesh of Knowles Electronics Manikin for Acoustic Research (KEMAR) show that in the context of complex geometries with local topology comparable to grid spacing such as the human pinna, the voxelization-related uncertainties in simulations emerge at lower frequencies than the generally used accuracy bandwidths. Numerical simulations show that the voxelization process induces both random error and algorithm-dependent bias in the simulated HRTF spectral features. Frequencies fr below which the random error is bounded by various dB thresholds are estimated and predicted. Particular shortcomings of the used voxelization algorithms are identified and the influence of the surface impedance on the induced errors is studied. Simulations are also validated against measurements.
头部相关传递函数（HRTF）所捕获的人耳廓周围的散射是一个复杂问题，在声学测量和模拟中都会产生不确定性。在由体素化过程产生的具有轴对齐阶梯边界的时域有限差分（FDTD）模拟框架内，针对一种实体和两种表面体素化算法，对在HRTF捕获的声场中传播的基于体素化的不确定性进行了量化。利用用于声学研究的Knowles电子人体模型（KEMAR）的激光扫描网格进行的模拟结果表明，在具有与网格间距相当的局部拓扑结构的复杂几何形状（如人耳廓）的情况下，模拟中与体素化相关的不确定性出现在比通常使用的精度带宽更低的频率处。数值模拟表明，体素化过程在模拟的HRTF频谱特征中会引起随机误差和与算法相关的偏差。估计并预测了随机误差受各种分贝阈值限制的频率fr。识别了所使用的体素化算法的特定缺点，并研究了表面阻抗对所引起误差的影响。模拟也通过测量进行了验证。
