Audio-Visual Mixed Reality Representation of Hazard Zones for Safe Pedestrian Navigation of a Space

It is difficult to estimate the boundaries of the hazard zones generated around autonomous machines and robots when navigating a space shared with them. We investigated the use of multimodal (auditory and/or visual) mixed-reality (MR) displays to warn users about invading such hazards zones and to help them return to safety. Two single-modality auditory and visual displays were designed, which were subjectively comparable as generic hazard displays. An experimental user study was then conducted to compare the designed single-modality displays as well as an audio-visual display that combined both. When the display included auditory information, users returned sooner to safety, although this had a small effect on performance when carrying out an independent navigation task. Additional nuanced possible differences are reported and discussed in relation to display design characteristics, as well as in relation to the limitations of the implementations that are possible with current MR head-mounted display devices.