55 lines
1.4 KiB
Python
55 lines
1.4 KiB
Python
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from PIL import Image
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from numpy import random
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from torchvision import transforms
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import numpy as np
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import torch
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class Cutout(object):
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"""Randomly mask out one or more patches from an image.
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Args:
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n_holes (int): Number of patches to cut out of each image.
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length (int): The length (in pixels) of each square patch.
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"""
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def __init__(self, n_holes, length):
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self.n_holes = n_holes
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self.length = length
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def __call__(self, img):
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"""
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Args:
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img (Tensor): Tensor image of size (C, H, W).
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Returns:
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Tensor: Image with n_holes of dimension length x length cut out of it.
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"""
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from_PIL = False
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if type(img) == Image.Image:
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from_PIL = True
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img = transforms.ToTensor()(img)
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h = img.size(1)
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w = img.size(2)
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mask = np.ones((h, w), np.float32)
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for n in range(self.n_holes):
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y = random.randint(0, h)
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x = random.randint(0, w)
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y1 = np.clip(y - self.length // 2, 0, h)
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y2 = np.clip(y + self.length // 2, 0, h)
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x1 = np.clip(x - self.length // 2, 0, w)
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x2 = np.clip(x + self.length // 2, 0, w)
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mask[y1: y2, x1: x2] = 0.
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mask = torch.from_numpy(mask)
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mask = mask.expand_as(img)
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img = img * mask
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if from_PIL:
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img = transforms.ToPILImage()(img)
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return img
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