ALPR matcher technique: Number of character differences - Security Center 5.12

Security Center Administrator Guide 5.12
Product
Security Center
Content type
Guides > Administrator guides
Version
5.12
Language
English
Last updated
2024-09-13

The ALPR matcher uses the "Number of character differences" technique to improve the plate read accuracy rate.

This technique allows for a difference in the number of characters between the plate read and the plate number in the hotlist. This allows the system to account for characters in the plate that cannot be read (dirt, bad camera angle, and so on), and for objects on the plate that might be mistaken for legitimate characters (screws, pictures, and so on).

In the following example, the hotlist contains the license plate ABC123. The ALPR matcher configured to allow for one difference in the number of characters.

Does the hotlist contain the plate A 123 BC ? U Does the hotlist contain the plate AB 123 ? UO License plate Plate read A 123 BC UO Two stickers look like “U" and “O”. Plate read A 123 BC U A sports team sticker looks like a “U". License plate One additional character Two additional characters Does the hotlist contain the plate A 123 BC ? License plate Plate read A 123 BC Same number of characters Yes Hit on BC A 123 Yes Hit on BC A 123 No Does the hotlist contain plate a with plus or minus one character? No Does the hotlist contain plate a with plus or minus one character? No No h it on BC A 123

  • ABCU123 matches the plate ABC123 because you allowed one difference in the number of characters. With this configuration, a license plate with one more or one fewer characters generates a hit.
  • ABUO123 does not match the plate ABC123 because it has more than one additional character.
Parent topic: ALPR matcher
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