说明：  face_recognition.py文件是利用主成分分析进行ORL人脸识别的代码。该代码主要按照PCA的原理，利用累积贡献率来确定 主成分个数。通过降维，最后进行识别。
(Face_recognition.py file is the code of ORL face recognition using principal component analysis. According to the principle of PCA, this code uses the cumulative contribution rate to determine the number of principal components. Through dimension reduction, the recognition is finally carried out.)