basic_model.py 文件源码

def applyColorAugmentation(self, img, std=0.55, gamma=2.5):
    '''Applies random color augmentation following [1].  An additional gamma
    transformation is added.

    [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), -1.3 * std, 1.3 * std)
    perturbation = self.data_evecs.dot((alpha * np.sqrt(self.data_evals)).T)
    gamma = 1.0 - sum(perturbation) / gamma
    return np.power(np.clip(img + perturbation, 0., 1.), gamma)
    return np.clip((img + perturbation), 0., 1.)