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2.5 Side of road installation
Figure 9.
Typical side-fire road installation
– one lane per Drive5 system (with optional external flash)
2.6 Flash considerations
The Drive5 system comes equipped with a built-in on-axis LED illuminator (LED Ring Light) designed
to capture nighttime images of retro-reflective number plates, or to enhance the brightness of daytime
plate images in shade conditions or under cloudy or foggy skies.
For illumination of both plates
and
vehicles under nighttime conditions, the Drive5 system can be
integrated with the optional TNL-50 external flash unit. By positioning this high-powered flash unit a
short distance away from the Drive5, proper exposure of the overall scene can be achieved without
overexposing the plate. Table 1 below shows the minimum distance from Drive5 to flash/light unit
(distance normal from camera-license plate axis):
Drive 5
Unit to Flash Spacing (minimum)
Approximate distance in feet
3.25
Approximate distance in meters
1.0
Table 1
Minimum spacing distance between Drive5 and flash/light unit
If the flash is positioned closer to the camera, reflections from retro-reflective license plates will likely
cause overexposure. Tests have shown that positioning the flash up to two meters (6.5 feet) away
from the Drive5 will generally produce good results.
