手写数字样本库的下载地址

http://www.cs.nyu.edu/~roweis/data.html

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: 0 1 2 3 4 5 6 7 8 9 ]
  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.