ImageDataGenerator does not standartize validation_data

[eyaler]

ImageDataGenerator should apply standartize() on validation_data parameter or at least the docs should mention the the validation data is assumed to already be standartized

[fchollet]

There seems to be some confusion between ImageDataGenerator and fit_generator here. What do you mean?

[eyaler]

e.g. in the cifar10_cnn.py example, if you add featurewise normalization, in ImageDataGenerator, the fit_generator does not apply this normalization to validation_data=X_test

[asmith26]

Regarding the doc, I came across this also - it looks like the ImageDataGenerator doc is not being automatically generated, and hence the actual signature is not being pulled and updating the doc (with the default of featurewise_std_normalization=False).

I was about to add the ImageDataGenerator class to be automatically updated, however it looks like that class may be soon re-written (see #2446), so I'll hold off for now.

[eyaler]

please reopen. this is still an issue. i missed the stale tag.