Calibrating the SharpV zoom and focus - SharpV | SharpOS 12.7

AutoVu Handbook for SharpV Fixed Installations 12.7

series
SharpV | SharpOS 12.7
revised_modified
2019-08-21

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

  • 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. 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 adjust the focus.

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 LPR camera. The optimal size of license plate characters is 30 pixels high.
  • The position of the zoom and focus adjustment screws on the context camera might be reversed depending on whether you are installing the SharpV SR (Standard-Range) or LR (Long-Range). Refer to the product sticker on the camera for specific adjustment screw information.
    NOTE: Information on context cameras is not applicable to SharpV ITS cameras.

Zoom and focus adjustment screws

The SharpV includes zoom and focus adjustment screws for the LPR camera and the context camera. You can access the adjustment screws by removing the rubber plugs on the bottom of the camera. A hex key is provided for making the adjustments.

The following information appears on the zoom / focus adjustment label:

Label Description
Zoom: T/W Telephoto/wide
Focus: F/N Far/near
LPR / CTX LPR camera/context camera
SR / LR Standard range/long range

Procedure

  1. Open the Sharp Portal https://<Sharp name or IP address>.
    By default, the SharpV is configured to use DHCP. If no DHCP server is available on the network, you can use the IP address 192.168.10.100 to access the SharpV.
  2. If this is the first time you are logging on the portal, you are prompted to change the password for security reasons. For more information, see Logging on to the SharpOS 12.7 Portal for the first time.
    NOTE: If you forget your password, you can reset it from the logon page.
  3. From the Configuration menu, select the Zoom and focus page.
  4. From the Select your camera drop-down list, select the LPR Camera.
    The live feed of the LPR camera is displayed.
  5. Adjust the exposure as required for the best plate image.
    NOTE: The SharpV camera only uses the exposure setting that are visible in the Zoom and Focus page during the adjustment process. After the camera has been adjusted, this setting is ignored and the camera returns to the configured exposition settings.
  6. Adjust the camera's zoom level.
    1. Select Show ruler. A ruler is displayed on the LPR camera image. Drag the ruler so that it appears next to the license plate.
    2. Enter a new pixel (px) value to change the size of the ruler on the page to match the height of the license plate characters.
    3. Adjust the zoom and alignment so that the image has the largest field of view and the longest plate transit time, while keeping the height of the plate characters in the image between 25 - 60 pixels. The optimal performance is 30 pixels.
      NOTE: When you change the camera's zoom level, the focus is lost. You need to perform a basic focus adjustment each time you change the zoom level so that you have a relatively clear view of the license plate.
      Tip: Click on the license plate to use digital zoom. 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.

  7. Adjust the camera focus.
    1. Focus the camera on a stationary plate located at the mid-point of the vehicle's expected trajectory.
    2. Click the image to digitally zoom in on the plate.
      NOTE:
      • Use the Best score graph to visually monitor when the optimal setting is reached for the focus while you are adjusting the screws on the bottom of the SharpV, two orange lines are displayed. The 'bold' orange line indicates the current focus value. The 'dim' orange line indicates the best focus that has been achieved since the graph was last reset.
      • For best results, make sure that there is no movement in the camera's field of view when using the Best score graph.

      Example:

    3. Click Reset to start the focus adjustment (1).
    4. Start turning the focus adjustment screw for the LPR camera (2). For this example, the screw is being turned clockwise.
      Both the bold and dim orange lines move higher on the graph and are intersecting.
    5. At a certain point, the bold line starts to move lower on the graph and the lines are no longer intersecting (3). At this point you have exceeded the best focus.
      It is important to note that the dim orange line now displays the best focus point.
    6. Start turning the adjustment screw in the opposite direction (for this example, counter-clockwise).
    7. When the bold line reaches the level of the dim line (4), the focus adjustment is completed. Click Done.

    To adjust the zoom and focus of the context camera:

    Adjust the context camera using the same method described for the LPR camera, with the following exceptions:

    • You can focus the camera's context image based on the image's sharpness, but you can also use the graph tool to help you fine-tune the focus.
    • 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 Configuration > Zoom and focus > Enable flash. 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 very bright conditions (sunlight), you might need to use very 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 very bright sunlight.
    NOTE: Information on context cameras is not applicable to SharpV ITS cameras.
  8. Click Done.