AES Europe 2025

Individual head-related transfer functions (HRTFs) are instrumental in rendering plausible spatial audio playback over headphones as well as in understanding auditory perception. Nowadays, the numerical calculation of individual HRTFs is achievable even without high-performance computers. However, the main obstacle is the acquisition of a mesh of the pinnae with a submillimeter accuracy. One approach to this problem is the photogrammetric reconstruction (PR), which estimates a 3D shape from 2D input, e.g., photos. Albeit easy to use, this approach comes with a trade-off in the resulting mesh quality, which subsequently has a substantial impact on the HRTF's quality. In this study, we investigated the effect of PR on HRTF quality as compared to HRTFs calculated from a reference mesh acquired with a high-quality structured-light scanner. Additionally, we applied two pinna deformation methods, which registered a non-individual high-quality pinna to the individual low-quality PR pinna by means of geometric distances. We investigated the potential of these methods to improve the quality of the PR-based pinna meshes. Our evaluation involved the geometrical, acoustical, and psychoacoustical domains including a sound-localization experiment with 9 participants. Our results show that neither PR nor PR-improvement methods were able to provide individual HRTFs of sufficient quality, indicating that without extensive pre- or post-processing, PR provides too little individual detail in the HRTF-relevant pinna regions.