To ensure that the SharpV reads license plates clearly and that the plate characters appear in an acceptable size, you must adjust the zoom and focus of your SharpV camera.
Before you begin
- Verify your SharpV hardware revision. Instructions are included below for G1, G2, and G3 hardware revision. For more information on SharpV G1 and G2 hardware revisions, see the AutoVu™ SharpV Installation Guide.
- Read about optimal reading distance for plate reads for the SharpV.
- Install a stationary license plate to adjust the SharpV camera's zoom and focus.
NOTE: You can use the target license plate included with the AutoVu.
If this necessitates closing a lane of traffic, observe all local regulations. Alternatively, you can adjust the zoom and focus by pointing the camera to the side of the street and placing the stationary plate at the expected distance for plate reads. When the camera is pointed back to the traffic lane, you must evaluate plate read images to fine-tune the focus, if required.
- Ensure that the camera lens is clean.
What you should know
- The system captures plate reads more accurately if characters are between 25 and 60
pixels high in the images acquired by the ALPR camera. The optimal size of license
plate characters is 30 pixels high.NOTE: If the SharpV is configured for dual-lane plate reading, the characters must be from 10 to 40 pixels high. For more information, see Configuring the SharpV to monitor dual lanes.
- If the field of view has already been set for the camera, you must set it again following the focus and zoom calibration.
Procedure
-
Click the image to digitally zoom in on the plate.
Tip: There are three zoom levels: 1:1, 2:1, and 4:1. A preview of the zoomed area is displayed in the top-right corner of the image.
-
For best results, make sure that there is no movement in the camera's field of
view during the autofocus calibration. The calibration takes approximately 45
seconds.
- SharpV G3
- Click Autofocus.
The graph and the focus slider move as the autofocus calibration proceeds. After about 45 seconds, the Stop autofocus button changes back to Autofocus, signaling that the calibration is complete.
NOTE: If required, you can use the + and - buttons to fine-tune the focus. - SharpV G1 and G2
- Adjust the focus using the adjustment screws.
For more information, see the AutoVu™
SharpV Installation Guide. For an
example, you can watch the video. NOTE: The Best score graph shows you when the optimal setting is reached for the focus. Two orange lines are displayed; the bright orange line indicates the current focus value. The dim orange line indicates the best focus that has been achieved since the Reset button was last pressed.
Example:
Calibration progress Description A Click Reset. B Starting to turn the adjustment screw clockwise. C The screw has been turned too far clockwise and has now moved away from the Best score line. D Turning the screw counter-clockwise until the two lines meet. To adjust the zoom and focus of the context camera:Adjust the context camera using the same method described for the ALPR camera, with the following exceptions:
- The pixel height of the license plate characters is not important when adjusting the context camera. You must only ensure that the vehicle is clear and recognizable in the image.
- If you need to adjust the zoom and focus of the context camera in low light conditions, enable the IR illuminator. To enable the IR illuminator, click . The IR illuminator enables you to see the image more clearly; however, the video feed from the context camera is converted to a black and white image.
- If you adjust the zoom and focus of the context camera in bright conditions (sunlight), you might need to use a low level on the exposure level slider. At very low levels, the camera iris aperture is reduced. If the focus is adjusted in this position, the result might not be optimal because focus quality can degrade in lower light conditions. The web portal displays a warning to indicate when such conditions exist. To achieve the best possible focus quality, you should not adjust the focus in bright sunlight.