Two-camera based accurate vehicle speed measurement using average speed at a fixed point
David Fernández Llorca, Carlota Salinas, M. Jimenez, I. Parra, Álvaro García Morcillo, Rubén Izquierdo, Javier Lorenzo, Miguel Ángel Sotelo · 2016
In this paper we present a novel two-camera-based accurate vehicle speed detection system. Two high-resolution cameras, with high-speed and narrow field of view, are mounted on a fixed pole. Using different focal lengths and orientations, each camera points to a different stretch of the road. Unlike standard average speed cameras, where the cameras are separated by several kilometers and the errors in measurement of distance can be in the order of several meters, our approach deals with a short stretch of a few meters, which involves a challenging scenario where distance estimation errors should be in the order of centimeters. The relative distance of the vehicles w.r.t. the cameras is computed using the license plate as a known reference. We demonstrate that there is a specific geometry between the cameras that minimizes the speed error. The system was tested on a real scenario using a vehicle equipped with DGPS to compute ground truth speed values. The obtained results validate the proposal with maximum speed errors <; 3kmh at speeds up to 80kmh.