LPR is an image-processing technology used to identify vehicles by their license plates. The License Plate detection in video stream consists of 3 main steps:

  • Motion detection (background subtraction).
  • When motion is detected, license plate detection engine for still image (a LPB Feature-based Cascade detector) is activated.
  • When license plate is detected, license plate tracking (Kalman filter) module is activated. Few good images will be selected from the track of a license plate, to be processed in next phase.

Usage Scenarios

This technology is used in various security and traffic applications, such as the access-control system and smart traffic system.

Solution & Technologies

  • Segmentation & rectification: ASM (active shape model).
  • OCR (optical character recognition): template matching.
  • Vietnamese and Japanese license plates.


  • Stable under different camera positions and angles and different weather conditions.
  • Average accuracy of 96.5%.
Click on uploaded picture on the right or upload a new picture of a Japanese license plate and click Analyse to see the result.