In this embodiment, the speed of the vehicle can be measured in real time by a speed measuring module. The speed measuring module may be mounted under the ground, on a side of the road, or on the top of the line scan camera depending on installation requirements. The speed measuring module may employ speed measurement with a video, radar, photoelectric switch, or ground sensing coil according to different measurement principles. Optionally, the speed measuring module may use a video to measuring the speed, that is, the speed measuring module includes an image capturing module, such as a speed measuring camera. At this point, such speed measuring module has the advantages of small volume, high anti-interference, high real-time performance, wide speed measuring range, adaptation to various types of vehicles, and easy realization of waterproof and pressure-proof functions.

Step 102: determining line frequency for image capturing according to the speed of the incoming vehicle.

At step 102, the line frequency for image capturing is determined according to the speed of the vehicle.

In this embodiment, a line scan camera is employed to capture images of the chassis of the vehicle, in order to improve the resolution of the captured images of the chassis of the vehicle.

In this embodiment, the line frequency for image capturing is determined according to the speed of the vehicle. As an optional implementation, the line frequency for image capturing is determined according to the speed of the vehicle, the number of pixels per one row of the line scan camera and a preset scale factor. For example, the line frequency for image capturing can be determined according to the following formula:
Q=k*w*v;