一种改进模板匹配的车牌字符识别方法

313Vol.31,No.320106JournalofHebeiUniversityofScienceandTechnologyJune2010:1008-1542(2010)06-0236-04王建霞,周万珍(河北科技大学信息科学与工程学院,河北石家庄050018):提出了一种改进模板匹配的车牌字符识别方法详细介绍了车牌字符识别的过程,主要包括模板的建立,基于弹性网格的字符特征提取,模板匹配的步骤及改进方法运用该方法不仅可减少计算量,而且提高了实时性实验结果表明,提出的方法具有效率高精确度好等特点,识别率可以达到90%以上:字符分割;车牌牌照;特征提取;字符识别;改进模板匹配法:TP391:AAlicenseplatecharactersrecognitionmethodbasedonimprovedtemplatematchingWANGJian-xia,ZHOUWan-zhen(CollegeofInformationScienceandEngineering,HebeiUniversityofScienceandTechnology,ShijiazhuangHebei050018,China)Abstract:Thispaperpresentsanimprovedtemplatematchingmethodoflicenseplatecharactersrecognition.Licenseplatecharactersrecognitionprocessisintroducedindetail,whichincludestheestablishmentofthetemplate,thecharacterfeatureextractionbasedonanelasticmesh,templatematchingstepsandimprovedmethods.Byusingthismethod,thecomputationalamountisgreatlyreduced,whilerea-ltimeisimproved.Theexperimentalresultshowsthattheproposedmethodhashigheff-iciency,accuracyandgoodcharacteristics,andtherecognitionratecanreach90%.Keywords:characterssegmentation;licensevehicleplate;featureextraction;charactersrecognition;improvedtemplatematchingmethod:2009-12-24;::(1970-),,,,,,,3[1],11,[2],,,1,,,[3],[4];,,,[5]261050,,,,,,,[6]22.1,GA3620071026,,3216,2.2,,,2.2.1,,,,,,,,,,,,1图1均匀网格和弹性网格对比图Fig.1Uniformgridandflexiblemeshcomparisonchart2.2.2,,,,,,2f(x,y),1),,,,Hor(i),Ver(j),MN,:Hor(i)=Nj=1f(i,j),i=1,2,,M;(1)Ver(j)=Mi=1f(i,j),j=1,2,,N(2)2373图2弹性网格划分图Fig.2Flexiblemeshdivisionchart2),,,,,1,,,,3),,4),,5),2.3m:w1,w2,,wm,,wi,Xi=xi1xi2xi3xin,(3)X,X=x1x2x3xn(4)d(Xi,X),i,d(Xi,X)d(Xj,X),j=1,2,,m,ij,(5)Xwi,X,Xi|X-Xi|2,d(X,Xi)=|X-Xi|2=(X-Xi)T(X-Xi)=XTX-XTXi-XTiX+XTiXi=XTX-(XTXi+XTiX-XTiXi),(6)XTXi+XTiX-XTiXi,:di(X)=XTXi+XTiX-XTiXi,(7)d(X,Xi)=min{di(X)},Xwi2.41)XXid(X,Xi)=|X-Xi|22),,2.5,,,A8,8,B18,1826,,B,B,A,,X1X2X3X4X5X6X7,X1,;X2,;X3X4X5X6X71)X1,,()23820102)2,,3)X2,,4)X3X4X5X6X7,3,,,1表1字符识别测试表Tab.1Characterrecognitiontesttable//()/%()/ms50045390.6/88.7289/315/50046092.0/90.7192/23050046993.8/91.0263/28750047895.6/92.4154/1951,,1000,2000,,,4,,,500,:[1],.[J].(ApplicationResearchofComputers),2009,26(5):1703-1705.[2],,.BP[J].(ComputerEngineering&Sc-ience),2009,31(5):59-61.[3],,.[J].(ComputerEngineeringandDesign),2008,29(6):1568-1570.[4].BP[J].(JournalofChongqingCollegeofElectronicEng-ineering),2009,18(2):90-94.[5],.[J].(Microelectronics&Computer),2008,25(6):101-104.[6],,,.[J].(JournalofHebeiUniversityofScienceandTechnology),2008,29(4):295-298.不断进取,开拓创新2393