| 摘要 |
A method and system for determining the speed of a vehicle 116 comprising receiving images 208 of the vehicle 116 captured at known time intervals by a camera 202; determining a point (520, Fig. 5a, 522, Fig. 5b) at which a tyre of the vehicle 116 contacts the road in each image; using the points of contact (520, Fig. 5a, 522, Fig. 5b) and time intervals to calculate the speed of the vehicle 116. The camera 202 may capture still or video pictures 208 and may communicate with a computer 206 including a processor and memory. The two dimensional positions of the contact points (520, Fig. 5a, 522, Fig. 5b) in video frames 208 may be estimated and used with geometry to calculate three dimensional positions of the touch points (520, Fig. 5a, 522, Fig. 5b). The position of the license plate (510, Fig. 5a, 512, Fig. 5b) or lights of the vehicle may be established and the 2D estimated position of the contact points (520, Fig. 5a, 522, Fig. 5b) may be based on the location of the number plate (510, Fig. 5a, 512, Fig. 5b) or lights. The camera 202 may be calibrated so that pixel locations in the images 208 are known relative to real-world 3D coordinates. The calculated speed may be a mean, median, maximum, minimum or varying speed. |
