Introduction to ANPR

ANPR, sometimes known by other terms, such as Automatic License Plate Recognition (ALPR), Automatic Vehicle Identification (AVI), or car plate recognition (CPR), is a surveillance method that uses optical character recognition (OCR) and other methods such as segmentation and detection to read vehicle registration plates.

The best results in an ANPR system can be obtained with an infrared (IR) camera, because the segmentation steps for detection and OCR segmentation are easy and clean, and they minimize errors. This is due to the laws of light, the basic one being that the angle of incidence equals Angle reflection. We can see this basic reflection when we see a smooth surface, such as a plane mirror. Reflection off rough surfaces such as paper leads to a type of reflection known as scatter or diffuse reflection. However, the majority of the country plates have a special characteristic named Retroreflection: the surface of the plate is made with a material that is covered...