Support for the outdoor walking of people with low vision using visual filter and augmented reality

Background Low-vision impairment refers to a vision or visual disability that cannot be improved by medical or optical means. People with low vision used to use their remaining vision to solve the problems they encounter in everyday life. However, existing auxiliary devices are mostly suitable for reading text or viewing display screens indoors, but auxiliary devices for outdoor situations are rare. Methods In this study, we conducted in-depth interviews of people with low vision who encounter vulnerable situations or obstacles while walking. Stairs, building entrances, bollards, sidewalk obstacles, and crosswalks were found to be the most difficult situations that people suffering from low vision experienced during outdoor walking. We proposed four visual aids through head-mounted display(HMD) that are expected to assist people with low vision on their outdoor walks by enabling them to recognize their surroundings more clearly. The four aids were contrast filter, contour filter, simple augmented reality(AR), and delicate AR. Then, in order to evaluate the effectiveness of each aid, we conducted an experiment with visual images reflecting each aid. Results The perception of the peripheral environment of people with low vision was most accurate when they utilized the AR aids. Especially, with the AR aids, highlighting the obstacles' shapes without abstraction showed the highest task success rate and satisfaction over all situations. On the other hand, the visual filters that can enhance the contrast and contour of the obstacles resulted in lower perception accuracy than when filters were not used. Conclusions In order to support the outdoor walking of people with low vision through the use of HMD or smart phones, it is most desirable to employ an augmented reality that can emphasize the shapes of major obstacles, the directions of roads, and the signals of traffic lights.