JAI IIT Camera Systems VIS-CAM 400 - Manual (Page 15)

Installation Preparation 15
IIT Camera System Manual
2 Preparing for installation
2.1 Preparation for installation
As mentioned in the previous section is it essential for the function of the IIT Camera that the
license plate moves through the sensitive region when the vehicle passes the camera.
2.1.1 Over Lane Positioning
Over lane camera mounting is always employed when the road width being monitored contains more
than two lanes of traffic, when a convenient overhead is already in place, or when preventing
vandalism is a paramount concern.
Figure 5. Typical Over Lane Site Layout
Note: Diagram applies to both front and rear plate geometries. With any configuration, the distance
between camera and license plate must be in between 10m and 20m.
2.1.2 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 20º to 30º is recommended – with 25º 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.
We strongly recommend not using angles outside this region as the amount of reflectance from the
license plates decreases when the angle of incident increases causing reduced performance of the
system and license plate image is distorted.