中文说明：用PCA进行手写数字识别，主要是用matlab实现了原始图像的预处理，进而分别采用传统的PCA方法、改进的PCA算法和2维PCA算法进行了数字识别。
English Description：
Using PCA for handwritten numeral recognition is mainly to realize the preprocessing of the original image with MATLAB, and then use the traditional PCA method, improved PCA algorithm and two-dimensional PCA algorithm for numeral recognition.