3 Image Enhancement 3.3.1 Histogram Equalization (HE) How to HE based on the relationship The formula of HE If's =T(r)=(L-1)fo Pr(w)dwthen p.(s)= 10ss≤L-1 Cumulative distribution function(CDF)is used as the HE transform function Proof:Because s=T(r)=(L-1)p,(w)dw So aT(r)d[(L-1)SPr(w)dw] dr =(L-1)p(r) dr substitute p.(s)=p.((r) 1 =p(r)*亿-10p) L-1 随机变量s具有均匀PDF表征 第3章第8页 3 Image Enhancement 第3章 第8页 3.3.1 Histogram Equalization (HE) How to HE based on the relationship The formula of HE Proof: ,then ,0s L-1 Because so substitute 1 ( ) ( ) ( ) / s r p s p r dT r dr  Cumulative distribution function (CDF) is used as the HE transform function 随机变量s具有均匀PDF表征