data_preparation.py 文件源码

def applyColorAugmentation(img, std=0.5):
  '''Applies random color augmentation following [1].

  [1] Alex Krizhevsky, Ilya Sutskever, Geoffrey E. Hinton. \
    ImageNet Classification with Deep Convolutional Neural Networks. \
    NIPS 2012.'''

  alpha = np.clip(np.random.normal(0, std, size=3), -2 * std, 2. * std)
  perturbation = sld_evecs.dot((alpha * np.sqrt(sld_evals)).T)
  gamma = 1.0 - sum(perturbation) / 3.
  return np.power(np.clip(img + perturbation, 0., 1.), gamma)
  return np.clip((img + perturbation), 0., 1.)