Virtual Haptic Map Using Force Display Device for Visually Impaired

Abstract

We propose a new virtual haptic map system using a force display device and a GPS receiver. This system can haptically display the roads, city blocks, and buildings which are automatically constructed from a numerical map given in DXF format and the information on current location and orientation from a GPS receiver. Hence this system will be especially useful for supporting outdoor activities of visually impaired persons. Other features of the system are that the map can be customized easily with respect to various characteristics such as a concave-convex shape of the objects or friction of surfaces in accordance with the user's need and that the position and orientation of the map can be changed automatically in real time. To evaluate the usability of this system, recognition experiments using simple virtual haptic maps were conducted by ten blindfolded subjects. In the experiments, recognition rates were compared between two representation methods. In the first method the area of road is concaved, and in the second method it is convexed. As a result, high recognition rates were confirmed in both methods, and it shows that this system has reasonable usability. Additionally, we found that concaved areas were touched for longer time than convexed areas. This suggests that important information is better to be displayed by concave parts. We have also developed a mobile robot system with our virtual haptic map system which is aimed at navigating a visually impaired person and supporting outdoor activity. A preliminary experiment is shown for the validity of this mobile robot system.