Bilinear and triangular spherical head-related transfer functions interpolation on non-uniform meshes

Spatial audio or 3D audio refers to a set of techniques whose main objective is to simulate sound sources located in arbitrary positions in space. This is possible thanks to the Head-Related Transfer Functions (HRTFs), which model the anatomical characteristics of the subject and their interaction with the incident sound field. Since HRTFs are measured at discrete positions in space, interpolation techniques such as Bilinear or Triangular Spherical are necessary. However, both methods require uniform interpolation meshes. Hence, in this work, we propose a new methodology to HRTFs databases measured on non-uniform meshes for the bilinear and triangular spherical interpolation methods. Our results suggest that our proposed methodology for bilinear and triangular spherical interpolations can be used as a viable alternative for non-uniform meshes. We evaluate our approach in terms of spectral distortion, achieving similar results when compared to spline interpolation as a baseline.