Experimental Analysis of a Spatialised Audio Interface for People with Visual Impairments

Sound perception is a fundamental skill for many people with severe sight impairments. The research presented in this article is part of an ongoing project with the aim to create a mobile guidance aid to help people with vision impairments find objects within an unknown indoor environment. This system requires an effective non-visual interface and uses bone-conduction headphones to transmit audio instructions to the user. It has been implemented and tested with spatialised audio cues, which convey the direction of a predefined target in 3D space. We present an in-depth evaluation of the audio interface with several experiments that involve a large number of participants, both blindfolded and with actual visual impairments, and analyse the pros and cons of our design choices. In addition to producing results comparable to the state-of-the-art, we found that Fitts's Law (a predictive model for human movement) provides a suitable metric that can be used to improve and refine the quality of the audio interface in future mobile navigation aids.