One-parameter camera calibration for traffic management cameras
F.W. Cathey, D.J. Dailey · 2005
Assuming a standard pinhole camera model, we show that there is a calibrating "scale factor" and a simple formula that relates the change in distance along a line parallel to the highway direction to a change in the image vertical coordinate. Using this scale factor, we can estimate vehicle speeds by tracking vehicle images in successive time-tagged images.