JAI TS-2030EN 사용자 설명서

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VIS-CAM System 
 
 
 
6
 
 
Preparing for Installation
 
 
Figure 4.  Typical Over Lane Site Layout Plan. 
 
2.1.1 (a) Camera tilt considerations 
The requirement to freeze the motion of high-speed vehicles limits how steep or shallow the tilt 
angle of the camera may be. For example, it is important to prevent the horizon from appearing in 
the image, and thereby allowing the sun to blind the camera. For over lane installations, a camera 
tilt between 20° to 30° is recommended–with 25° being considered the optimal angle. This angle of 
tilt is the best compromise between minimizing visibility blockages caused by closely spaced 
vehicles and maximizing plate visibility for plate mounts that are slightly recessed or tilted 
downwards. 
2.1.1 (b) Asynchronous triggering considerations 
When the VIS is operated in trigger mode, a vehicle detector is employed to cause the camera to 
capture an image at the precise moment the vehicle is in the best position to image both the 
vehicle and its license plate. The delay between the time the vehicle passes the trigger position on 
the road and when the trigger signal actually reaches the VIS must be kept to a minimum to prevent 
high-speed vehicles from moving out of the area viewed by the camera before the image is snapped. 
2.1.1 (c) Camera height versus trigger distance considerations 
It is critically important, to select the correct distance between the camera and the location on the 
road where the camera is triggered to capture an image. Minimizing the cost of installation is 
usually also an important concern. This means that whenever possible, it is best to use existing 
structures or previously installed elements. The following charts (Figure 5 and Figure 6) provide a 
wide range of trade-offs between camera height and trigger distance to enable the installer to 
select convenient camera and light sensor locations relative to existing mounting structures and 
vehicle trigger locations. Adhering to the installation options provided in the installation charts, 
yields camera images that are generally suitable for automatic license plate readers (ALPR). 
To use the charts correctly, please follow the steps below. 
1.  First measure the height above the road to convenient camera mounting locations. 
2.  Measure the distance along the road from directly beneath each candidate camera position to 
convenient trigger locations.