Comparison of Non-Parametric Interpolation Techniques for Sparsely Measured Binaural Room Impulse Responses

This study investigates different interpolation techniques for spatially upsampling Binaural Room Impulse Responses (BRIRs) measured on a sparse grid of view orientations. In this context, the authors recently presented the Spherical Array Interpolation by Time Alignment (SARITA) method for interpolating spherical microphone array signals with a limited number of microphones, which is adapted for the spatial upsampling of sparse BRIR datasets in the present work. SARITA is compared with two existing nonparametric BRIR-interpolation methods and naive linear interpolation. The study provides a technical and perceptual analysis of the interpolation performance. The results show the suitability of all interpolation methods apart from linear interpolation to achieving a realistic auralization, even for very sparse BRIR sets. For angular resolutions of 30° and real-world stimuli, most participants could not distinguish SARITA from an artifact-free reference.