Real-Time Global Localization of Robotic Cars in Lane Level via Lane Marking Detection and Shape Registration

In this paper, we propose an accurate and real-time positioning method for robotic cars in urban environments. The proposed method uses a robust lane marking detection algorithm, as well as an efficient shape registration algorithm between the detected lane markings and a GPS-based road shape prior, to improve the robustness and accuracy of the global localization of a robotic car. We show that, by formulating the positioning problem in a relative sense, we can estimate the global localization of a car in real time and bound its absolute error in the centimeter level by a cross-validation scheme. The cross-validation scheme integrates the vision-based lane marking detection with the shape registration, and it improves the accuracy and robustness of the overall localization system. The GPS localization can be refined by using lane marking detection when the GPS suffers from frequent satellite signal masking or blockage, whereas lane marking detection is validated and completed by the GPS-based road shape prior when it does not work well in adverse weather conditions or with poor lane signatures. We extensively evaluate the proposed method with a single forward-looking camera mounted on an autonomous vehicle that travels at 60 km/h through several urban street scenes.