Research And Design Of Vehicle License Plate Recognition System

In recent years, China’s highway traffic cause of the rapid development of intelligenttransportation system, more and more people’s attention. With the full implementation of theintelligent transportation system, the vehicle license plate automatic recognition technologybecomes more and more important, as the only car license plate identification information,application of license plate recognition system will be more and more widely. And therelevant license plate technology has become more and more important research topic,research institutions and business school.The vehicle license plate recognition system of license plate images shot by the camera,the integrated use of images of many domestic and foreign latest algorithm and the patternrecognition method of threshold segmentation, smoothing, edge detection and imagesegmentation of the image processing to extract the plate region after complete, then on thelicense plate location, segmentation and process to complete the recognition of car licenseplate character. License plate recognition mainly includes three parts: license plate location,character segmentation, character recognition.This paper mainly based on the current situation of the license plate recognitiontechnology existing at home and abroad, combined with the relevant knowledge andtechniques of computer software engineering and the school of computer programminglanguage, the vehicle license plate recognition system is the requirement analysis andfeasibility analysis, analysis, through the study of characteristics of the vehicle license plate,combined with prior knowledge of license plate character, in order to Microsoft VC++6.0asthe platform, using the OpenCV computer vision library MFC image database and Microsoft’s Intel, has developed an automatic car license plate recognition system. This overall designand the use of system design, and system design and detailed design in detail the main work isas follows:Certain pretreatment including gray, two values, Gauss filtering, Canny edge detectionand processing the collected images, remove the noise and interference in the video dots.Horizontal segmentation, vertical segmentation and the plate size normalization function ofpositioning based on license plate image after pretreatment, and use the library OpenCV function of the license plate location well segmented, save for the standard image size.Character segmentation of license plate characters and the vertical projection ratio based onthe combination of the7character segmentation. Finally the segmented by template matchingmethod of license plate character and the character template matching feature values, so as toachieve character recognition effect. The main function is as follows:Image preprocessing: pretreatment of license plate image collected, improve correctrecognition rate.License plate location: from the captured image, take some algorithm, find out thelicense plate region.Character segmentation: from the segmentation of license plate area is good, thecharacter image segmentation, save for a single character image.Character recognition: identify the correct character literals in each character image.At the end of the license plate recognition system has been completed, a selection ofsome of the image contains the license plate, vehicle license plate recognition system usingthe rate for detailed testing of the function and identification, after testing we found, thesystem has the character recognition effect is very good, the identification accuracy, speed,and the software easy to use, operation is simple and easy to understand.