About SharpZ3 exposure adjustment - SharpZ3 | SharpOS 13.1

SharpZ3 Administrator Guide 13.1

Applies to
SharpZ3 | SharpOS 13.1
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Guides > Administrator guides

We recommend that you keep the default SharpZ3 exposure settings. If you notice that license plates are often under-exposed (too dark) or over-exposed (too bright), you can adjust the exposure settings. However, there are many factors to consider in order to account for changing lighting conditions.

IMPORTANT: Modifying the SharpZ3 exposure settings can greatly impact ALPR performance. Vanity plates, or plates that are damaged or dirty can have different reflective properties. Improving the exposure using a stationary test plate can result in reduced ALPR performance on every-day traffic which includes plates with a wide range of reflective properties. You must test the system after modifying these settings.

Consider the following:

  • 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.
  • 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 SharpZ3 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.