CCTV Technical Report--Phase 3

The Washington Department of Transportation (WSDOT) has a network of several hundred closed-circuit television (CCTV) traffic surveillance cameras deployed on the freeways and arterials around Seattle for congestion monitoring. No camera parameters are known a priori for these cameras; WSDOT operators dynamically change their focal length (f), pan angle (theta), and tilt angle (phi). The goal of this project was to create algorithms and prototype software to allow these cameras to be used to make continuous quantitative measurements of vehicle speed. However, to use the cameras for quantitative measures, the camera parameters have to be estimated. In order to measure speeds of vehicles from a series of video images it is not necessary to completely calibrate the camera; rather, by using the vanishing point of lines in the image algebraic constraints can be established on the parameters that are sufficient to straighten the image and compute a scale factor for estimating speed.