Echolocation as a Means for People with Visual Impairment (PVI) to Acquire Spatial Knowledge of Virtual Space

Abstract

In virtual environments, spatial information is communicated visually. This prevents people with visual impairment (PVI) from accessing such spaces. In this article, we investigate whether echolocation could be used as a tool to convey spatial information by answering the following research questions: What features of virtual space can be perceived by PVI through the use of echolocation? How does active echolocation support PVI in acquiring spatial knowledge of a virtual space? And what are PVI’s opinions regarding the use of echolocation to acquire landmark and survey knowledge of virtual space? To answer these questions, we conducted a two-part within-subjects experiment with 12 people who were blind or had a visual impairment and found that size and materials of rooms and 90-degree turns were detectable through echolocation, participants preferred using echoes derived from footsteps rather than from artificial sound pulses, and echolocation supported the acquisition of mental maps of a virtual space. Ultimately, we propose that appropriately designed echolocation in virtual environments improves understanding of spatial information and access to digital games for PVI.

A Participatory Design Approach to Creating Echolocation-Enabled Virtual Environments

“…For example, Wu et al [103] used pre-recorded sounds and echoes in a grid-like maze to teach people how to use echolocation; Andreasen et al [6] argued that the use of echolocation may improve ownership over the virtual space, Neidhardt et al [65] and Pelegrin et al [70] used their implementation of echolocation to ind out whether participants could identify a virtual wall and orient themselves towards it. Dodsworth et al [28] and Andrade et al [5] argued that echolocation may assist people with visual impairment in acquiring spatial information and forming a mental map of virtual space.…”

“…Chebot et al [19] provide a comprehensive review of existing sensory substitution approaches to assist with acquisition of spatial knowledge. Although the examples presented by Chebot et al focus on the physical world, it is clear that a form of sensory substitution occurs in virtual worlds when, for example, sound or vibrations are used to support exploration [5,106].…”

“…As digital games, VR and AR experiences become more common, it is necessary to develop mechanisms for these experiences to be accessible by designÐinstead of retroitting accessibility features, these should be included by default in the design process [64]. Works such as that of Zhao et al [106], who have developed a tool that provides a series of visual and audio augmentations to make VR more accessible to people with low vision, and Andrade et al [5] who argue for the use of echolocation to convey spatial information in virtual space, provide initial examples on how new tools and sensory substitution approaches could help deliver digital experiences that are accessible by default. However, these approaches to accessibility need to be developed in consultation with the target population to ensure that the unique perspective and skills of people with visual impairment are leveraged as a source of knowledge and that the solution being produced is not just yet another "disability dongle" [41].…”

“…In order to reach an understanding about the goals of the current project, participants were required to irst follow the protocol outlined in our previous research, presented in [5]. In this protocol, participants used an echolocation-enabled virtual environment to identify: size of virtual rooms, the material a virtual room was made of, the presence of 90-degree turns, and the presence of openings and obstacles.…”

“…Some of this research has attempted to replicate echolocationÐthe use of sound and echoes produced by sound relecting of diferent surfaces [50,51]Ðto improve accessibility in digital games and VR experiences for people with visual impairment [2,6,28,58,70,84,103]. Echolocation has been used, for example, to help detect obstacles [77,84], and to support the formation of mental maps of virtual space [5,28,40,58]. However, more work is needed to ensure that echolocation in virtual spaces responds to the needs of people with visual impairment.…”