Research On License Plate Location Algorithm In The Complex Background

With the continuous improvement of people's living standards and the advances in technology,automobile has penetrated each household and it has become an essential tool for people to travel.As the increasing number of motor vehicles on the road,traffic congestion,congestion,illegal and other issues become more and more,how to effectively manage the vehicle has become an important field of intelligent transportation research.The license plate recognition technology based on digital image processing and pattern recognition mainly extract license plate from complex background and identify it.Through preprocessing,license plate location,character segmentation and character recognition technology,it can identify the license plate number and provide a strong guarantee for intelligent transportation systems achieve vehicle management.Today license plate recognition technology has been applied to the road toll,parking and vehicle management district,urban road traffic management and other occasions,and it has broad application prospects.The license plate location is an essential module in plate recognition technology,it also has important significance and value.The paper describes the basic principle of the license plate recognition technology and basic modules in detail,discusses the basic features of the license plate area,analysis the basic principles,advantages and disadvantages of the current domestic and foreign common license plate location algorithms,and elaborates the difficulties in locating the license plate.In addition,the image processing technology and the principle,feature extraction and matching process of local image feature extraction and matching SURF algorithm are analyzed and described.The main research work are as follows:(1)Making full use of geometry,texture and color characteristics of the license plate area,this paper proposes a license plate location algorithm which is based on HSI color space and line scanning.Firstly,it uses the vehicle license plate color to segment the image,combines with the area,ration of geometric features in the license to obtain a license plate candidate region.And then combined with the texture plates,it use line scanning algorithm to analysis the number of consecutive jumps of each row in candidate regions to determine the license plate of the upper and lower boundaries.In order to get the left and right borders of the license plate,it use verticalprojection algorithm.Through comparative analysis of the experiment,the algorithm has better positioning effect.(2)Through analysis the deficiencies of using SIFT algorithm to locate the license plate in complex background,and combined with the advantages of image feature extraction and matching SURF algorithm and the full use of multi-feature license plate,it proposes a license plate location method which is based on multi-feature and SURF algorithm.First,it uses the colors,geometric and texture features to get the license plate candidate region,and then it use SURF algorithm to extract the license plate characters standard template library and the candidate region image to match feature,positioning plate area precisely.Finally,through the comparative analysis of the experiment,the algorithm not only has good results in time and accurate rate,but also it can achieve the recognition of the license plate of the first Chinese character,reducing the burden on the subsequent character recognition.