Setting SharpV ALPR camera exposure levels for reflective and non-reflective plates - 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 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.

Before you begin

  • Adjust the zoom and focus of the camera.
  • 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.

    Under-exposed Correctly-exposed Over-exposed

    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.

Procedure

Adjust the ALPR camera in darkness:

  1. Log on to the Sharp Portal.
  2. From the Configuration menu, click Cameras > Exposure.
  3. From the Select your camera menu, select the ALPR camera.
    The live feed from the ALPR camera is displayed.
  4. From the Exposure menu, select Reflective and non-reflective.
    The camera automatically detects the lighting conditions and selects the Night adjustment.
  5. 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.
  6. Move the Reflective plates slider towards the right as much as possible without over-exposing the image.
  7. Clear the Iris check box and move the slider to the right as much as possible without over-exposing image.
  8. 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 under sunlight:

  1. Log on to the Sharp Portal.
  2. From the Configuration menu, click Cameras > Exposure.
  3. 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.
  4. 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.
  5. Move the Reflective plates slider to the right as much as possible without over-exposing the image.
  6. Do not adjust the Iris settings. The adjustment you made for the night configuration also applies for the sunlight configuration.
  7. 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.
Parent topic: About SharpV exposure adjustment for outdoor installations