中文说明：基于主成分分析(PCA)的人脸识别系统利用2D PCA算法求对训练集向量进行降维的降维矩阵，最近邻法测试对测试集识别的精度
English Description：
In the face recognition system based on principal component analysis (PCA), 2D PCA algorithm is used to calculate the dimension reduction matrix of training set vector, and the nearest neighbor method is used to test the recognition accuracy of test set