一种改进的Otsu阈值分割算法

　26　12200912MICROELECTRONICS&COMPUTERVol.26　No.12December2009:2008-11-05Otsu胡　斌,宫宁生(,210009)　:Otsu法是一个常用的阈值分割方法.该算法是基于一维直方图来确定阈值的,因此仅适合图像目标和背景分布呈正态分布且各像素量和方差基本相当的情况.针对这个不足,文中提出了一种结合邻域信息的改进Otsu算法.实验结果表明,改进算法比传统的Otsu算法有更好的分割效果.:图像分割;阈值选取;Otsu法;数字图像处理:TP391　　　　　:A　　　　　:1000-7180(2009)12-0153-03AnImprovedOtsu'sThresholdingSegmentationMethodHUBin,GONGNing-sheng(NanjingUniversityofTechnology,Nanjing210009,China)Abstract:Otsu'smethodisafrequentlyusedthresholdingsegmentationmethod.Becausethethresholdselectiondependsontheonedimensionalhistogram,Otsu'smethodisonlysuitablefortheprobabilitymodelsofimagetargetandback-groundhavingnormaldistribution.Inordertosolvetheproblem,animprovedOtsu'smethodwhichutilizestheinforma-tionofedgeregionispresentedinthispaper.Experimentalresultsshowthattheimprovedmethodcangetbettersegmen-tationeffectthanthatofOtsu'smethod.Keywords:imagesegmentation;thresholdselection;Otsu'smethod;digitalimageprocessing1　,.,(),..,、、、[1-2].:、、Otsu、P、[3].Otsu,,,.Otsu.,Otsu,,,[4].,Otsu,Otsu,,.,Otsu[5-6].2　OtsuOtsu,“”“”.,[7].Kurita,,Otsu;,.Otsu,.Brink,Otsu.,Otsu[8].,.:L,ini,:N=n0+n1+…+nL-1:pi=niN,∑L-1i=0pi=1.T:C0(0T)C1(T+1L-1).C0C1:ω0=Pr(C0)=∑Ti=0pi=ω(T)ω1=Pr(C1)=∑L-1i=T+1pi=1-ω(T)ω0+ω1=1:μ0=∑Ti=0ip/ω0=μ(T)/ω(T)μ1=∑L-1i=T+1ip/ω1=μ-μ(T)1-ω(T),μ(T)=∑Ti=0ipi,μ=μ(L-1)=∑L-1i=0ipi.μ,.C0C1:σ0=∑Ti=0(i-μ0)2pi/ω0σ1=∑L-1i=T+1(i-μ1)2pi/ω1:σB=ω0(μ0-μ)2+ω1(μ1-μ)2=ω0ω1(μ1-μ0)2T[0,L-1],σBTOtsu.3　Otsu,OUST.,,,,,[6].,.Otsu.:、,,,.,.,Otsu.:(1)f(i,j);(2),,T0、T1,minGray、maxGray、;(3)f(i,j),f(i-1,j)、f(i+1,j)、f(i,j-1)、f(i,j+1)4,f(i,j)T0f(i,j)T1,f(i,j)=0.25×(|f(i-1,j)-f(i,j)|+|f(i+1,j)-f(i,j)|+|f(i,j-1)-f(i,j)|+|f(i,j+1)-f(i,j)|)+f(i,j),;(4)Otsu,T[α,β],α=2＊T0-minGray,β=2＊T1-maxGray.4　VC++OtsuOtsu.3256×256,256,Otsu,1.15420091　OtsuTT17391241593181154,Otsu,,.1.,T[α,β],OtsuT[0,L-1],.1　5　,Otsu.Otsu,Otsu..:[1].[J].,2000,5A(6):466-469.[2],,.[J].,2004,9(6):674-678.[3],,,.[J].,2008,25(6):71-73.[4],,.[J].,2008,25(7):134-141.[5],,.[J].,2002,23(1):106-108.[6],,.Otsu[J].,2008,38(4):4-7.[7],,.[J].,2003(1):77-80.[8],.Otsu[J].,2006(26):14-15.:　　,(1982-),..　,(1958-),,..155　12,:Otsu