A Situation context aware Dempster-Shafer fusion of digital maps and a road sign recognition system

Speed limit information systems solely based on one modality can hardly overcome their respective intrinsic disadvantages: Digital maps lack support for short-term changes brought by variable message signs and road works, while camera based systems cannot recognize implicit speed limits and may fail in adverse lighting scenarios. In this work we show a fusion approach that is able to overcome these limitations. It is specifically tailored to our task by adapting sensor reliability based on the perceived situation context. This enables the camera based system to easily outvote the digital map in a construction site or the digital map to veto against uncertain camera recognition results during nighttime. The proposed fusion approach was implemented and evaluated on a qualitative base showing very promising results: The situation context aware fusion is able to deduce the correct effective speed limit even when one of the sensors fails. Moreover, it reduces conflicts encountered between the sources compared to a not situation context aware fusion.