Setting SharpV ALPR camera exposure levels for reflective and non-reflective plates - SharpV | SharpOS 13.2

AutoVu™ SharpV Administrator Guide 13.2

Applies to
SharpV | SharpOS 13.2
Last updated
2020-09-16
Content type
Guides
Guides > Administrator guides
Language
English (United States)
Product
SharpOS
SharpV
Version
13.2

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. As a result, a license plate only appears with the correct exposure in half of the image frames. This means that when the system selects the best image to associate with a plate read, fewer possible candidates are available.
  • 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.

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: For this adjustment, ignore the exposure of any reflective plates in the video feed.
  6. Move the Reflective plates slider towards the right as much as possible without over-exposing the image.
    NOTE: For this adjustment, ignore the exposure of any non-reflective plates in the video feed.
  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: For this adjustment, ignore the exposure of any reflective plates in the video feed.
  5. Move the Reflective plates slider to the right as much as possible without over-exposing the image.
    NOTE: For this adjustment, ignore the exposure of any non-reflective plates in the video feed.
  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.