说明：  比较深入的分析了PCA人脸识别方法的原理，并对PCA在应用过程中遇到的特征值选择和距离准则问题进行了研究，实现了基于PCA算法的人脸识别。
(First, the thesis investigates principle component analysis (PCA) approachdeeply, and then the choice of feature vector of sample s covariance matrix anddistance measure criterion are discussed. PCA approach can approximate the original data with lower dimension feature vector. )