基于监控视频图像的车辆测速方法(视频测速)的工作原理，提出了一种视频测速的实现思路，指出了在间隔已知时间的视频帧图像中找到对应块是实现视频测速的关键和难点。对车灯的特征进行了分析，根据车灯区域的特征，提出了采用灰度差水平叠加投影的方法，构造可以代表其鼓形区域的函数，以其作为定位车灯带的判别函数，并根据车灯的特点进行候选块筛选的一种简单快速的车灯区域定位方法，可在平均13ms内准确定位到车灯区域，从而为这一高速条件下视频测速的关键难点提出了一种切实可行的解决办法。

This paper proposed a real time vehicle speed measurement algorithm based on video image monitoring. According to the speed equation, to get the speed, if we have two images which the acquisition time between them is known, we need to look for a way to get the position of same block in the two images. In this paper, the theory, implementation flowchart and the key points of the algorithm were presented. A fast vehicle lamp locating method based on vehicle lamp characteristic and horizontal gray level difference projection was provided to solve the main difficulty of the algorithm. The experimental result and the problems that could be resolved in the future were discussed in the end, and the block can be located in 13ms meantime on a conventional 800MHz Intel Pentium III. According the data of result in experiment, the accuracy of speed measurement could probably achieve more than 92%. It shows the possibility to offer a real time system to measure speed of vehicle by video only. Because of the simple algorithm, the system can be implemented on a wide range of small low power devices, including embedded processors.