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import random
from PIL import ImageFilter


class GaussianBlur:
    """
    Gaussian blur augmentation in SimCLR https://arxiv.org/abs/2002.05709
    Adapted from MoCo:
    https://github.com/facebookresearch/moco/blob/master/moco/loader.py
    Note that this implementation does not seem to be exactly the same as
    described in SimCLR.
    """

    def __init__(self, sigma=[0.1, 2.0]):
        self.sigma = sigma

    def __call__(self, x):
        sigma = random.uniform(self.sigma[0], self.sigma[1])
        x = x.filter(ImageFilter.GaussianBlur(radius=sigma))
        return x
