Interpolation and Range Extrapolation of Head-Related Transfer Functions using Virtual Local Wave Field Synthesis

Virtual environments which are based on binaural sound reproduction require datasets of head-related transfer functions (HRTFs). Ideally, these HRTFs are available for every possible position of a virtual sound source. However, in order to reduce measurement efforts, such datasets are typically only available for various source directions but only for one or very few distances. This paper presents a method for extrapolation of measured HRTF datasets from the source distance used in the measurements to other source distances. The method applies the concept of local Wave Field Synthesis to compute extrapolated HRTFs for almost arbitrary source positions with high accuracy. The method is computationally efficient and numerically stable.