Estimation of the Visibility Distance by Stereovision: A Generic Approach
Nicolas Hautière · IEICE Transactions on Information and Systems · 2006
An atmospheric visibility measurement system capable of quantifying the most common operating range of onboard exteroceptive sensors is a key parameter in the creation of driving assistance systems.This information is then utilized to adapt sensor operations and processing or to alert the driver that the onboard assistance system is momentarily inoperative.Moreover, a system capable of either detecting the presence of fog or estimating visibility distances constitutes in itself a driving aid.In this paper, we present a technique to estimate the mobilized visibility distance through use of onboard CCD cameras.This distance represents the distance to the most distant object on the road surface having a contrast above 5 %.This defini- tion is very close to the definition of the meteorological visibility distance proposed by the International Commission on Illumination (CIE).Our method combines the computations of a depth map of the vehicle environment using stereovision and of local contrasts above 5 %.In this paper, both methods are described separately.Then, their combination is detailed.Our method is operative in every kind of meteorological conditions and is evaluated thanks to video sequences under sunny weather and foggy weather.