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A. A. Kalia, G. E. Legge, R. Roy; Indoor Route-Finding Technology Increases Independence for the Visually Impaired. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4476. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Wayfinding inside buildings is a common problem faced by people with visual impairment. Adaptive technology incorporating GPS and associated digital maps is available for outdoor wayfinding, but there is no equivalent technology for indoor wayfinding. To address this problem, we have developed a software called Building Navigator, analogous to geographic information systems used in outdoor navigation, that conveys the spatial layout of indoor floor plans via synthetic speech. The software can plan routes between arbitrary locations on a floor and guide users along the routes via a sequence of waypoints. Distance to waypoints is provided in three different units: feet, number of steps, and time in seconds, with individual calibration for step length and walking speed. The goal of this study was to determine whether the route-finding feature of Building Navigator allows users to navigate more independently than without the technology.
Blindfolded normally-sighted and visually impaired participants navigated through four building layouts counterbalanced across four conditions: technology with distance in feet, steps, and seconds, and no technology. For each condition, participants were tested on four routes to unfamiliar target rooms. Independent mobility was measured by the number of "bystander queries" required by the participant to reach the target room. The bystander (played by the experimenter) gave the current room location and the direction of travel to reach the target room. The experimenter recorded the number of bystander queries made by the participant. Other measurements included the path and time taken to find a room, and whether the room was successfully located.
Both normally-sighted and visually impaired participants were able to find most of the target rooms with or without the technology. Both groups made on average 5-6 bystander queries per route when the technology was not available. With the technology, they averaged 1-2 queries per route. This difference was significant for both normally-sighted (t(11) = 14.55, p<0.001) and for visually impaired participants (t(4) = 4.8184, p < 0.01). Normally-sighted participants took significantly less time finding rooms with the technology than without the technology (t(11) = 2.4821, p < 0.05) and there was no statistically significant difference for visually impaired participants.
Route instructions effectively enhance independent indoor navigation, and do not increase the time required to find a location. Route instructions are a desirable feature of indoor wayfinding technology for the visually impaired.
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