| 摘要 |
The invention relates to a method and device for determining traffic condition quantities, such as traffic flow speed and traffic density, on the basis of gray scale values of a video image established by a video camera, during which the video camera records video images of a traffic lane traveled by vehicles. The aim of the invention is to provide a method and device with which traffic condition quantities are reliably determined, which functions in a self-calibrating manner, and with which an automatic recognition of faults and the provision of information regarding the causes thereof is made possible. To this end, the invention provides that: in a video image, a measuring range is specified over the course of the depicted traffic lane; individual gray scale values are determined from partial ranges of the measuring range; a gray scale value function is established; a transformation of the gray scale function into an equalized gray scale function according to the camera angle is carried out; a first and a temporally shifted second gray scale function are determined; the shift of both functions relative to one another is determined using cross correlation, and; the calculation of the average spatial traffic flow speed ensues using a known scale in pixels per meter. |
