How to build
Automatic number plate recognition has two essential technological issues:
1. The quality of license plate recognition software
with its applied recognition algorithms, and
2. The quality of image acquisition technology,
the camera and the illumination.
The very key factor is the number plate recognition software. The sophistication of the recognition software, the intelligence and quality of the applied number plate recognition algorithms, the mathematical knowledge and the years of experience behind determines the capabilities of the recognition software. The better the algorithms are, the highest the quality of the recognition software is:
· the highest recognition accuracy it has,
· the fastest processing speed it has,
· the most type of number plates it can handle,
· the widest range of picture quality it can handle,
· the most tolerant against distortions of input data it is.
The key technological parts of an APNR system
We believe that there are two key technological parts of a number plate recognition algorithm that basically determines its quality level:
· a robust, very high accuracy and intelligent optical character recognition technology, and
· a technology that allows intelligent structural analysis of complex higher structures.
The robust, high accuracy Optical Character Recognition (OCR) technology is an essential requirement.
The image acquisition technology determines the average image quality the number plate recognition algorithm has to work on. Needless to say that the better the quality of the input images are, the better conditions the number plate recognition algorithm has, and thus the higher number plate recognition accuracy can be expected to be achieved.