Determination of vehicle speed in traffic video

Abstract

In this paper, we present a semi real-time vehicle tracking algorithm to determine the speed of the vehicles in traffic from traffic cam video. The results of this work can be used for traffic control, security and safety both by government agencies and commercial organizations. The method described in this paper involves object feature identification, detection, and tracking in multiple video frames. The distance between vertical broken lane markers has been used to estimate absolute distances within each frame and convert pixel location coordinates to world coordinates. Speed calculations are made based on the calibrated pixel distances. Optical flow images have been computed and used for blob analysis to extract features representing moving objects. Some challenges exist in distinguishing among vehicles in uniform flow of traffic when the object are too close, are in low contrast with one another, and travel with the same or close to the same speed. In the absence of a ground truth for the actual speed of the tracked vehicles accuracy cannot be determined. However, the vehicle speeds in steady flow of traffic have been computed to within 5% of the speed limit on the analyzed highways in the video clips.