Anthropometric Individualization Of Head Related Transfer Functions Analysis And Modeling

Anthropometric Individualization of Head-Related Transfer Functions Analysis and Modeling

Human sound localization helps to pay attention to spatially separated speakers using interaural level and time differences as well as angle-dependent monaural spectral cues. In a monophonic teleconference, for instance, it is much more difficult to distinguish between different speakers due to missing binaural cues. Spatial positioning of the speakers by means of binaural reproduction methods using head-related transfer functions (HRTFs) enhances speech comprehension. These HRTFs are influenced by the torso, head and ear geometry as they describe the propagation path of the sound from a source to the ear canal entrance. Through this geometry-dependency, the HRTF is directional and subject-dependent. To enable a sufficient reproduction, individual HRTFs should be used. However, it is tremendously difficult to measure these HRTFs. For this reason this thesis proposes approaches to adapt the HRTFs applying individual anthropometric dimensions of a user. Since localization at low frequencies is mainly influenced by the interaural time difference, two models to adapt this difference are developed and compared with existing models. Furthermore, two approaches to adapt the spectral cues at higher frequencies are studied, improved and compared. Although the localization performance with individualized HRTFs is slightly worse than with individual HRTFs, it is nevertheless still better than with non-individual HRTFs, taking into account the measurement effort.

Head-Related Transfer Function and Acoustic Virtual Reality

This book covers all aspects of head-related transfer function (HRTF), from the fundamentals through to the latest applications, such as 3D sound systems. An introductory chapter defines HRTF, describes the coordinate system used in the book, and presents the most recent research achievements in the field. HRTF and sound localization in the horizontal and median planes are then explained, followed by discussion of individual differences in HRTF, solutions to this individuality (personalization of HRTF), and methods of sound image control for an arbitrary 3D direction, encompassing both classic theory and state of the art data. The relations between HRTF and sound image distance and between HRTF and speech intelligibility are fully explored, and measurement and signal processing methods for HRTF are examined in depth. Here, supplementary material is provided to enable readers to measure and analyze HRTF by themselves. In addition, some typical HRTF databases are compared. The final two chapters are devoted to the principles and applications of acoustic virtual reality. This clearly written book will be ideal for all who wish to learn about HRTF and how to use it in their research.

Frontiers in Signal Processing Editors’ Choice 2022