If the license plates in your region include both reflective and non-reflective
plates, you can configure the SharpV camera's
exposure settings to look for both plate types.
To calibrate the exposure, reflective and non-reflective plates must be visible in
the video feed. For best results, place stationary reflective and non-reflective
license plates as far from the camera as possible while still being within range for
the camera to capture plate reads. If this is not possible due to traffic, you can
still evaluate the exposure by monitoring moving vehicles, however, you must
familiarize yourself with local license plate types so that you can visually identify
reflective and non-reflective plates in the image.
What you should know
When you configure a SharpV for reflective
and non-reflective plates, each frame of the ALPR camera video feed alternates
between the optimal exposure settings for the two plate types. A menu is available in
the Cameras > Exposure page that lets you display only reflective or non-reflective
plates.
The following procedure includes steps that must be performed in darkness followed
by steps that must be performed in sunlight. You can calibrate the exposure remotely
using the Sharp Portal, assuming the
required license plates are visible in the video feed.
In a correctly-exposed license plate image, the
characters and the plate state are dark and well-defined, and the background is
white or very bright.
IMPORTANT: Modifying the exposure settings can greatly impact ALPR
performance. You must test the system after modifying these settings.
In the ALPR image, it is normal that the surroundings
of the plate are under-exposed while the plate itself is correctly-exposed. Make
sure that the plate is correctly exposed and ignore the quality of the
surroundings.
From the Configuration menu,
click Cameras > Exposure.
From the Select your camera menu,
select the ALPR camera.
The live feed from the ALPR camera is displayed.
From the Exposure menu, select Reflective and
non-reflective.
The camera automatically detects the lighting conditions and selects the
Night adjustment.
Move the Non-reflective plates slider to the right as much
as possible without over-exposing the image.
NOTE: When you move the slider for reflective or non-reflective plate
types, the live feed automatically displays only that plate type. You can manually
select the plate type using the menu on the right side of the live feed.
Move the Reflective plates slider towards the right as much
as possible without over-exposing the image.
Clear the Iris check box and move the slider to the right as
much as possible without over-exposing image.
When you are satisfied with the appearance of the plate images in the video feed
window, click Save.
The system displays the message Configuration saved
successfully.
From the Configuration menu,
click Cameras > Exposure.
From the Select your camera menu,
select the ALPR camera.
The live feed from the ALPR camera is displayed.
Reflective and non-reflective is already selected as
the Exposure type.
The camera automatically detects the lighting conditions and selects the
Sunlight adjustment.
Move the Non-reflective plates slider to the right as much
as possible without over-exposing the image.
NOTE: When you move the slider for reflective or non-reflective plate
types, the live feed automatically displays only that plate type. You can manually
select the plate type using the menu on the right side of the live feed.
Move the Reflective plates slider to the right as much as
possible without over-exposing the image.
Do not adjust the Iris settings. The adjustment you made for
the night configuration also applies for the sunlight configuration.
When you are satisfied with the appearance of the plate images in the video feed
window, click Save.
The system displays the message Configuration saved
successfully.