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import random
import torch
import torch.nn.functional as F
def DiffAugment(x, types=[]):
for p in types:
for f in AUGMENT_FNS[p]:
x = f(x)
return x.contiguous()
# """
# Augmentation functions got images as `x`
# where `x` is tensor with this dimensions:
# 0 - count of images
# 1 - channels
# 2 - width
# 3 - height of image
# """
def rand_brightness(x):
x = x + (torch.rand(x.size(0), 1, 1, 1, dtype=x.dtype, device=x.device) - 0.5)
return x
def rand_saturation(x):
x_mean = x.mean(dim=1, keepdim=True)
x = (x - x_mean) * (torch.rand(x.size(0), 1, 1, 1, dtype=x.dtype, device=x.device) * 2) + x_mean
return x
def rand_contrast(x):
x_mean = x.mean(dim=[1, 2, 3], keepdim=True)
x = (x - x_mean) * (torch.rand(x.size(0), 1, 1, 1, dtype=x.dtype, device=x.device) + 0.5) + x_mean
return x
def rand_translation(x, ratio=0.125):
shift_x, shift_y = int(x.size(2) * ratio + 0.5), int(x.size(3) * ratio + 0.5)
translation_x = torch.randint(-shift_x, shift_x + 1, size=[x.size(0), 1, 1], device=x.device)
translation_y = torch.randint(-shift_y, shift_y + 1, size=[x.size(0), 1, 1], device=x.device)
grid_batch, grid_x, grid_y = torch.meshgrid(
torch.arange(x.size(0), dtype=torch.long, device=x.device),
torch.arange(x.size(2), dtype=torch.long, device=x.device),
torch.arange(x.size(3), dtype=torch.long, device=x.device),
indexing = 'ij')
grid_x = torch.clamp(grid_x + translation_x + 1, 0, x.size(2) + 1)
grid_y = torch.clamp(grid_y + translation_y + 1, 0, x.size(3) + 1)
x_pad = F.pad(x, [1, 1, 1, 1, 0, 0, 0, 0])
x = x_pad.permute(0, 2, 3, 1).contiguous()[grid_batch, grid_x, grid_y].permute(0, 3, 1, 2)
return x
def rand_offset(x, ratio=1, ratio_h=1, ratio_v=1):
w, h = x.size(2), x.size(3)
imgs = []
for img in x.unbind(dim = 0):
max_h = int(w * ratio * ratio_h)
max_v = int(h * ratio * ratio_v)
value_h = random.randint(0, max_h) * 2 - max_h
value_v = random.randint(0, max_v) * 2 - max_v
if abs(value_h) > 0:
img = torch.roll(img, value_h, 2)
if abs(value_v) > 0:
img = torch.roll(img, value_v, 1)
imgs.append(img)
return torch.stack(imgs)
def rand_offset_h(x, ratio=1):
return rand_offset(x, ratio=1, ratio_h=ratio, ratio_v=0)
def rand_offset_v(x, ratio=1):
return rand_offset(x, ratio=1, ratio_h=0, ratio_v=ratio)
def rand_cutout(x, ratio=0.5):
cutout_size = int(x.size(2) * ratio + 0.5), int(x.size(3) * ratio + 0.5)
offset_x = torch.randint(0, x.size(2) + (1 - cutout_size[0] % 2), size=[x.size(0), 1, 1], device=x.device)
offset_y = torch.randint(0, x.size(3) + (1 - cutout_size[1] % 2), size=[x.size(0), 1, 1], device=x.device)
grid_batch, grid_x, grid_y = torch.meshgrid(
torch.arange(x.size(0), dtype=torch.long, device=x.device),
torch.arange(cutout_size[0], dtype=torch.long, device=x.device),
torch.arange(cutout_size[1], dtype=torch.long, device=x.device),
indexing = 'ij')
grid_x = torch.clamp(grid_x + offset_x - cutout_size[0] // 2, min=0, max=x.size(2) - 1)
grid_y = torch.clamp(grid_y + offset_y - cutout_size[1] // 2, min=0, max=x.size(3) - 1)
mask = torch.ones(x.size(0), x.size(2), x.size(3), dtype=x.dtype, device=x.device)
mask[grid_batch, grid_x, grid_y] = 0
x = x * mask.unsqueeze(1)
return x
AUGMENT_FNS = {
'color': [rand_brightness, rand_saturation, rand_contrast],
'offset': [rand_offset],
'offset_h': [rand_offset_h],
'offset_v': [rand_offset_v],
'translation': [rand_translation],
'cutout': [rand_cutout],
} |