Spatial representation framework for indoor navigation by people with visual impairment

A map is an artefact used for navigation that helps people find information on locations, landmarks and routes. Using GPS, outdoor travelling is easy with a free map service such as Google Map, which provides geographic information for navigation. However spatial information is rarely provided by any commercial products for indoor navigation. Navigation inside buildings is a problem for people with visual impairment, due to a lack of useful information about the interior space, e.g. landmarks, navigational cues, and hazards. The research problem is thus to find an appropriate framework for spatial representation (SRF) that can be used to define spaces and buildings, and is aimed at indoor navigation by people with visual impairment. In this work, a spatial representation framework was developed using a list of problems and challenges that were uncovered through a field study. This was then validated by 30 visually impaired people, and also 15 experts working in related fields such as caregiver, orientation and mobility, and accessibility. The validated SRF consists of 11 components, arranged in five layers: structural, object, sensor, path, and wayfinding. A building rating system (BRS) was developed as an example of a SRF implementation, aimed at improving the accessibility of spaces and buildings for people with visual impairment. BRS grades spaces and buildings, and informs people with visual impairment about the level of accessibility provided. It uses a similar approach to WCAG 2.0, using Conformance A, AA, and AAA representing minimum, sufficient, and full accessibility, respectively. The BRS was validated by 5 experts in each of three groups: research and development, accessibility, and building and interior design. Then, the BRS was evaluated using System Usability Scores. It was rated 72.2 SUS (Good) by 3 focus groups of 3 building and interior risk assessors. The outcomes from using BRS can be used as recommendations to improve spaces and building organisation. The SRF can be used as a platform for other indoor-based applications