Vision-based Assistive Navigation Algorithm for Blind and Visually Impaired People Using Monocular Camera

摘要

The system aims to develop an algorithm, to be implemented in an open-source platform, that facilitate the navigation, and early door/window detection process, for people with visual difficulties in closed environments. The proposed algorithm relies in a three stage image process consisting of the removal of all unwanted information through grayscale conversion and edge detection (image pre-processing), followed by the second stage formed by the search of lines or patterns on the detected edges, with the help of a first order Hough Transform, in order to locate a region where the majority of these lines intersect with each other, or vanishing point, which is the pivot point of the entire algorithm. Finally, the last stage consist on the estimation of the main regions of the aisle (walls, floor and ceiling) in order to perform an early detection of special regions in the walls, or candidates, that could lead to the detection of doors and windows. The main idea is that, after the image processing, the algorithm will return instructions to the subject, through a physical medium to make the corrections on his trajectory. It was found that the estimation of the vanishing point through the use of Hough transformation and the second-order edge detection method using open source software tools is a viable method for navigation in closed environments and even its possible to use the same image processing tools to estimate regions that could be easily consider as the main regions of the aisle. It’s been demonstrated that perform the early detection of candidates for doors is also possible using the same techniques.