Setting custom SharpV ALPR camera exposure levels for outdoor installations - SharpV

Setting custom SharpV ALPR camera exposure levels for outdoor installations - SharpV | SharpOS 13.6

AutoVu™ SharpV Deployment Guide 13.6

Product

SharpOS

SharpV

Content type

Guides > User guides

Version

13.6

Language

English

Last updated

2022-07-19

If the default exposure settings do not produce acceptable results, you can adjust the iris, shutter time, and gain settings of the SharpV ALPR camera to work best with your outdoor installation.

Before you begin

Ensure that the lighting conditions match what is expected during normal camera operation.
Adjust the zoom and focus of the camera.

What you should know

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.
The ranges for the Exposure time and Gain settings must be large enough to allow good quality images in all lighting conditions, but you should reduce the range as much as possible. If the range is too large, it increases the risk of over-exposure or under-exposure. It is normal that the SharpV constantly varies the exposure of the ALPR camera in order to get a correct exposure of a plate.
Modifying settings to improve read performance at night can have a negative impact on read performance during the day, and vice versa. Therefore, you must test the settings both at night and during the day (under sun illumination).
If the SharpV is expected to read both embossed and flat license plates, perform the day instructions with the flat plate and the night instructions with the embossed plate.

Procedure

Adjust the ALPR camera under sun illumination:

Place a stationary license plate as close to the camera as possible while still being within range for the camera to capture plate reads.
Log on to the Sharp Portal.
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. Do not modify the focus. The license plate might appear out of focus, but you are only adjusting the exposure in these steps.
From the Exposure drop-down list, select Range (outdoor).
Gain, Exposure time and Iris settings are displayed.
Set the Gain and Exposure time minimum and maximum levels to their minimum values.
Clear the Iris check box.
Move the Iris slider towards 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.

Adjust the ALPR camera at night:

Place a stationary license plate as far from the camera as possible while still being within range for the camera to capture plate reads.
Log on to the Sharp Portal.
From the Configuration menu, select Cameras > Exposure.
From the Select your camera drop-down list, select the ALPR camera.
The live feed from the ALPR camera is displayed. Do not modify the focus. The license plate might appear out of focus, but you are only adjusting the exposure in these steps.
From the Exposure drop-down list, select Range (outdoor).
Gain, Exposure time and Iris settings are displayed.
Increase the Exposure Time maximum as much as possible without getting an over-exposed image.
If the Exposure Time is set at the maximum value and the image is still dark, increase the Gain maximum until you are satisfied with the 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.