input_pipline.py 文件源码

def image_preprocessing(image, train):
    """Decode and preprocess one image for evaluation or training.

    Args:
      image: JPEG
      train: boolean
    Returns:
      3-D float Tensor containing an appropriately scaled image

    Raises:
       ValueError: if user does not provide bounding box
    """
    with tf.name_scope('image_preprocessing'):
        if train:
            image = tf.image.random_flip_left_right(image)
            image = tf.image.random_brightness(image, 0.6)
            if FLAGS.image_channel >= 3:
                image = tf.image.random_saturation(image, 0.6, 1.4)
        # Finally, rescale to [-1,1] instead of [0, 1)
        image = tf.subtract(image, 0.5)
        image = tf.multiply(image, 2.0)
        image = tf.image.per_image_standardization(image)
        return image