Vision-based navigation using top-view transform and beam-ray model

This paper presents a vision-based navigation method for blind people in an outdoor sidewalk environment. Unlike many existing navigation systems that use stereo-vision based methods, the proposed method is able to get obstacle position as well as user motion information by using just single camera fixed at the belly of the user. To achieve this goal, a top-view image of the road is used for obstacle detection and user motion estimation, based on which a grid map is generated for navigation. Obstacles are detected by using a beam-ray model, while user motion is estimated by using optical flow in a user surrounding area. For navigation part, a step score is calculated on the grid map for evaluating the safety of next moving step. Experiments with several sidewalk video-clips show that the proposed navigation method is able to provide useful guidance instructions under certain sidewalk environments.