Measurement System for Personalized Head-Related Transfer Functions and Its Verification by Virtual Source Localization Trials with Visually Impaired and Sighted Individuals
Andrzej Dobrucki, Przemysław Plaskota, Piotr Pruchnicki, Michał Pec, Michał Bujacz, Paweł Strumiłło · Journal of the Audio Engineering Society · 2010
Filtering of sounds through head-related transfer functions (HRTFs) remains the most reliable method of producing spatialized virtual audio on headphones. The main difficulty in using HRTFs is their high dependence on the listener, that is, on the shape of his or her ears, head, and torso. A system was designed to measure personalized head-related impulse responses (HRIRs) efficiently for over one thousand locations around a listener in a relatively short time (about 10 min). The measurement procedure was specially targeted at visually impaired persons, as the reported work is part of a larger project aimed at constructing an electronic travel aid (ETA) for the blind. Verification trials measuring the accuracy of users attempting to localize virtual sound sources were conducted. The average errors in azimuth localization ranged from 6° to 14°, while for elevation they ranged from 9° to 24°, depending on the source's spectrum, its motion, and the listener. Thanks to the participation of blind volunteers it was possible to test the influence of the disability on localization errors and assess the capabilities of the designed ETA.