说明：  用于人脸特征提取的2D2DLDA、2D2DLPP、2D2DPCA算法，由原本的一维特征提取改善为二维特征提取，大大提高了其识别率。
(For facial feature extraction 2D2DLDA, 2D2DLPP, 2D2DPCA algorithm, from the original one-dimensional two-dimensional feature extraction feature extraction to improve, greatly improve the recognition rate.)