(英) |
Recently textured pavement blocks are utilized for visually impaired humans walking. However, it is still difficult for them to detect crosswalk. In this article, an image processing method is proposed to detect crosswalk and to notify the position and direction with voice guidance on a camera phone. First, lines are detected with Hough transform. Then through piecing short lines together and noise lines elimination, edges of crosswalk white lines are selected. Calculating the mean angle of the edges, the mean line which has the angle and crosses the median point of terminal points of the white lines is determined. Connected line of each median point of the terminal points in each side of the mean line shows crosswalk direction. To determine the start point, the near side median point is extended to the same distance between the overall median point. Finally, voice guidance informs the direction and start point. |