# Data Preprocessing

### From Ufldl

(→MNIST Handwritten Digits) |
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=== MNIST Handwritten Digits === | === MNIST Handwritten Digits === | ||

- | The MNIST dataset has pixel values in the range <math>[0, 255]</math>. We thus start with simple rescaling to shift the data into the range <math>[0, 1]</math>. In practice, removing the mean-value per example can also help feature learning. ''Note: While one could also elect to use PCA/ZCA whitening if desired, this is not often done in practice.'' | + | The MNIST dataset has pixel values in the range <math>[0, 255]</math>. We thus start with simple rescaling to shift the data into the range <math>[0, 1]</math>. In practice, removing the mean-value per example can also help feature learning. ''Note: While one could also elect to use PCA/ZCA whitening on MNIST if desired, this is not often done in practice.'' |