手写数字库很容易建立，但是总会很浪费时间。Google实验室的Corinna Cortes和纽约大学柯朗研究所的Yann LeCun建有一个手写数字数据库，训练库有60,000张手写数字图像，测试库有10,000张。
请访问原站 http://yann.lecun.com/exdb/mnist/
该数据库在一个文件中包含了所有图像，使用起来有所不便。如果我把每个图像分别保存，成了图像各自独立的数据库。
并在Google Code中托管。
如果你有需要，欢迎在此下载:
http://code.google.com/p/supplement-of-the-mnist-database-of-handwritten-digits/downloads/list
Handwritten Digits MNIST Handwritten Digits [data/mnist_all.mat]
[training pictures: 0 1 2 3 4 5 6 7 8 9 ]
[testing pictures: 0 1 2 3 4 5 6 7 8 9 ]
8-bit grayscale images of "0" through "9"; about 6K training examples of each class; 1K test examples USPS Handwritten Digits [data/usps_all.mat]
[pictures: 0123456789 ]
8-bit grayscale images of "0" through "9"; 1100 examples of each class. Binary Alphadigits [data/binaryalphadigs.mat] [picture]
Binary 20x16 digits of "0" through "9" and capital "A" through "Z". 39 examples of each class.
From Simon Lucas' (sml@essex.ac.uk), Algoval system.
另有提供matlab读取的MNIST、USPS、Binary Alphadigits数据库，Data for MATLAB hackers，见：http://www.cs.toronto.edu/~roweis/data.html
参考网址：
[1] http://yann.lecun.com/exdb/mnist/
[2] http://hi.baidu.com/ln0707/blog/item/8207ef010a243d81d53f7c03.html
[3] http://www.cs.toronto.edu/~roweis/data.html
[4] http://blog.csdn.net/onezeros/archive/2010/05/28/5631930.aspx
