Research On License Plate Location System
Zhou Rujie
(College of Engineering, South China Agricultural University, Guangzhou 510642,China)
Abstract: With the rapid development of our country city, traffic management has become a
very hot topic, due to traffic management and increasing demand, put forward higher request to
the traffic management and control. The traffic management system in intelligent, license plate
recognition technology (License Plate Recognition, LPR) is an important technology of vehicle
identification and monitoring, play a very important role in the city vehicle management.
License plate recognition technology is widely used in road illegal vehicle monitoring, parking
management, vehicle safety management. License plate recognition software system is divided
into three parts: license plate location, character segmentation and character recognition. This
paper makes research and discusses the algorithm of license plate location and character
segmentation method, according to the characteristic of license plate of a vehicle license plate
location and character segmentation of simple algorithm is proposed.
License plate location part uses the method of mathematical morphology, is realized by the
following steps: first use the radon function to skew detection and correction of the image, and
mathematical morphology processing by gray and edge detection, then can be carried out,
finally is the extraction of license plate region. Character segmentation is made using
projection method, analysis of pixel vertical projection histogram, with each character trough,
wave and plate custom standards to divide each character. Using image processing capabilities
of the MATLAB, through the preparation process, statistical analysis of vehicle image, to
achieve the functions of two parts.
The key of this method is the selection of appropriate structure elements, the license plate
image mathematical morphology open, close operation to remove the interference factors,
eliminating the noise and useless information, simple and intuitive, less interference by the
environment. Through the experiment, in this paper, license plate localization algorithm and
character segmentation method can achieve good effect.
Key words: license plate location character segmentation mathematical morphology
projection
