To ensure the recognition of the state license plates using the Bioiris software module, it is necessary to install and configure the video cameras in such a way that the following requirements are met:

Camera specifications
Video image
  • The symbols height for IP cameras should be not less than 20-30 px, for analog cameras - not less than 14-20 px, the stroke width should be not less than 2 px;
  • Minimum allowed contrast with evenly dirty number plate should not be less than 10% (the contrast differentiation of symbols to the background is 25 on 256 point scale);
  • Maximum allowed uneven dirtiness is not more than 12% (ratio of the dirty area of the number plate to its whole area);
  • Geometrical proportions of the number plate picture should not differ from such proportions of the number plate itself with more than 10%.
Camera positioning
  • The camera should be installed permanently

For correct license plate recognition, only China license plates should be installed on the vehicle. If the vehicle has both a China license plate and a Hong Kong and/or a Macau license plate, then the Chinese license plate may not be recognized correctly.

An example of a vehicle image, which license plate may not be recognized correctly:

Any deviation from the above requirements reduces the likelihood of correct number recognition.