是统计分析的一个重要理论. 4 @% n: s& k: S. IPrincipal ComponentsAnalysis (PCA). PCA is a useful statistical technique that has found application in 4 Q; d; w# X" }4 gfields such as face recognition and image compression, and is a common technique for+ Z' T* X0 ?" ]9 z2 A' e
finding patterns in data of high dimension.