Optical Illusion Induction System with Augmented Reality for Support of Ascending & Descending Stairs

Abstract

Fall in stair is a serious problem. The misidentification of the stair height is one of the cause of fall. This paper presents an optical illusion induction system with augmented reality for support of ascending and descending stairs. The head-mounted display shows the vertical on the stair edge when ascending or horizontal line on the stair surface when descending. Human showed the AR system to perceive the stair higher when ascending or narrower when descending than actual. We constructed the model of the foot clearance by optical illusion based on the contrast sensitive function approximated with Gaussian function. In experiment, 10 participants climb and descend with AR system while we measured the foot trajectory. As a result, the coefficient of determination is over 0.7 when ascending, over 0.6 when descending in all participants. Furthermore, the toe height is significant higher during AR system than before in ascending (p<0.05). And, the horizontal toe distance is significant lower during AR system than before in descending (p<0.05). We concluded that the AR system make the participants perceive the optical illusion so the foot clearance increased enough.