Video and Object Tracking for Speed Determination Using Aerial LiDAR

Video of an event recorded from a moving camera contains information not only useful for reconstructing the locations and timing of an event, but also the velocity of the camera attached to the moving object or vehicle. Determining the velocity of a video camera recording from a moving vehicle is useful for determining the vehicle’s velocity and can be compared with speeds calculated through other reconstruction methods, or to data from vehicle speed monitoring devices. After tracking the video, the positions and speeds of other objects within the video can also be determined. Video tracking analysis traditionally has required a site inspection to map the three-dimensional environment. In instances where there have been significant site changes, where there is limited or no site access, and where budgeting and timing constraints exist, a three-dimensional environment can be created using publicly available aerial imagery and aerial LiDAR. This paper presents a methodology for creating a three-dimensional environment and performing video tracking analysis without a site visit. To validate the methodology, a blind study was conducted where three different videos were tracked. Each video presented a different traffic scenario including oncoming traffic, cross traffic, and passing traffic. The speed of the vehicle from which the video was recorded was determined through the video tracking process, and speed was also determined for a second vehicle visible within the videos. The speed of both vehicles in each video was then compared to vehicle speeds measured with vehicle instrumentation using Harry’s LapTimer to evaluate the accuracy of vehicle speeds determined through video and object tracking.