Personalized head related transfer function measurement and verification through sound localization resolution

Filtering of sounds through head related transfer functions (HRTFs) is a common method for obtaining audio spatialization. HRTFs depend highly on an individual´s anatomy, especially head dimensions and outer ear shape. The paper describes a system designed for efficient measurement of personalized HRTFs and verification of the collected data on a group of volunteers. The main goal of utilizing personalized HRTFs was to obtain a high level of externalization, i.e. the illusion that a sound source is located outside one´s head, as well as a high resolution of sound localization. Measurement of the HRTFs, using the constructed equipment in an anechoic chamber, was performed for 15 volunteers (9 of them blind, as our current research concerns electronic travel aids for visually impaired). A series of trials were conducted, which verified the personalized HRTFs in externalization and localization quality. Average precision of localization of moving virtual sound sources reached 6.7° in azimuth and 10.6° in elevation. At the same time influence of other factors, such as the source type or movement, on sound localization was also tested.