A Novel Pixel-Based Method to Estimate the Instantaneous Velocity of a Vehicle from CCTV Images.

In traffic forensic identifications, it was usually unfavorable that estimated velocities of questioned vehicles derived from frame-based methods eventually turned out to be close to but a bit less than speed limits. In this paper, a novel pixel-based method was presented to estimate vehicles' relatively instantaneous velocities. First, two adjacent pixels' actual distance was acquired from the closed-circuit television (CCTV) images. Then, the instantaneous average velocity within this one frame interval time (FIT) was calculated out. The frame-based method and its evaluating result were also introduced in this paper. The results showed that the velocity estimated by this new pixel-based method was higher than which derived from the frame-based method. Employing this presented novel method in these cases, it could be more accurately identified whether or not the vehicles had exceeded the speed limits, and then the responsibilities could be consequently assigned impartially.