Augmenting GPS speed limit monitoring with road side visual information

Frequently drivers fail to be aware of the current speed limit at any given moment in time. Present commercial GPS navigation systems have functionality to warn drivers about speeding on the basis of the road type information stored in the map. Unfortunately any temporary restrictions (e.g. caused by road works) are not taken into account. The system we propose here combines advantages of GPS and an optic sensor for reliable current speed limit monitoring. Our solution was initially developed as standalone vision system presented in details in [3], although integrating it together with GPS navigation adds new features and allows correct operation in majority of European countries. Our vision system includes the detection and recognition of both numerical limit and national limit (cancellation) signs. The system utilizes RANSAC-based colour-shape detection of speed limit signs and neural network based recognition.