In the embodiment shown in FIG. 3, the system for acquiring an image of a chassis of a vehicle may further include: a first detecting module 16, which is arranged on a side of the speed measuring module 12 near where the vehicle is coming and configured to detect whether there is a vehicle. When a vehicle is detected, an incoming vehicle signal is generated and transmitted to the speed measuring module 12 to trigger the speed measuring module 12 to start measuring the speed of the vehicle. The provision of the first detecting module 16, the speed measuring module 12 can be automatically triggered to start the speed measurement.

In this embodiment, the first detecting module 16 can be electrically connected to the control module 13. When the first detecting module 16 detects that a vehicle is entering, an incoming vehicle signal is generated. When transmitting the incoming vehicle signal to the speed measuring module 12, the first detecting module may also transmits the incoming vehicle signal to the control module 13, so as to control the light filling module 15 to turn on the fill light. Here, the incoming vehicle signal can also be referred to as an incoming signal.

In this embodiment, the system for acquiring an image of a chassis of a vehicle may further include: a second detecting module 17, which is arranged on a side of the line scan camera 14 near where the vehicle leaves and is configured for detecting whether the vehicle is leaving. When the leaving of the vehicle is detected, an outgoing signal is generated and is transmitted to the control module 13, so as to trigger the control module 13 to stop the line scan camera 14 stopping the image capturing on the chassis of the vehicle.