Circular Road Sign Extraction from Street Level Images Using Colour, Shape and Texture Database Maps

Road signs are very important features for providing rules of navigation. Indeed, they are key landmarks when navigating on the roads. Their visual properties are very strong because they have been designed to be remarkable and unmissible objects. Road signs are thus key objects to enrich road model databases to generate roadbooks, shortest paths, etc. The automatic detection and recognition of road signs from images (together with objects such as road marks) is thus a key topic and issue for road model updating but also for tomorrow’s applications of these databases, i.e. driving assistance, and accurate localisation functions for autonomous navigation. Most of the previous work in image based road sign extraction deal with three following issues: