def featurewise_norm(x, mean=None, std=None, epsilon=1e-07):
 if mean:
  x = (x - mean)
 if std:
  x = (x / (std + epsilon))
 return x

def featurewise_norm ( x , mean = None , std = None , epsilon = 1e-07 ) : if mean : x = ( x - mean ) if std : x = ( x / ( std + epsilon ) ) return x
normalize every pixels by the same given mean and std .