Sonification of guidance data during road crossing for people with visual impairments or blindness

TL;DR

This paper explores auditory guidance methods for visually impaired pedestrians during road crossing, comparing sonification-based modes with speech messages, and finds a preference for sonification despite higher decoding effort.

Contribution

Introduces and evaluates two novel sonification-based auditory guidance modes for road crossing, offering an alternative to speech messages for visually impaired users.

Findings

No single guiding mode is best for all users.

Sonification modes are preferred by over two-thirds of users.

Decoding sonified instructions requires more effort than speech.

Abstract

In the last years several solutions were proposed to support people with visual impairments or blindness during road crossing. These solutions focus on computer vision techniques for recognizing pedestrian crosswalks and computing their relative position from the user. Instead, this contribution addresses a different problem; the design of an auditory interface that can effectively guide the user during road crossing. Two original auditory guiding modes based on data sonification are presented and compared with a guiding mode based on speech messages. Experimental evaluation shows that there is no guiding mode that is best suited for all test subjects. The average time to align and cross is not significantly different among the three guiding modes, and test subjects distribute their preferences for the best guiding mode almost uniformly among the three solutions. From the experiments it also emerges that higher effort is necessary for decoding the sonified instructions if compared to the speech instructions, and that test subjects require frequent `hints' (in the form of speech messages). Despite this, more than 2/3 of test subjects prefer one of the two guiding modes based on sonification. There are two main reasons for this: firstly, with speech messages it is harder to hear the sound of the environment, and secondly sonified messages convey information about the "quantity" of the expected movement.