Road sign-aided estimation of visibility conditions

Reduced visibility on roadways caused by localized fog can impact the traffic flow in many ways: traffic speed, travel time delay, reduced capacity and accident risks. This paper presents a novel approach to estimate visibility conditions using an onboard camera and a digital map. Based on a traffic sign detector´s characteristics in the fog, and registering detection by vision and information encoded in the map, we are able to accurately determine the current visual range in hazy conditions. Quantitative results are provided on a large experimental data set of driving environment with various level of fogginess.