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.