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self-supervised learning
barlow-twins
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mix-bt / augmentations /augmentations_tiny.py
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# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Base augmentations operators."""
import numpy as np
from PIL import Image, ImageOps, ImageEnhance
# ImageNet code should change this value
IMAGE_SIZE = 64
import torch
from torchvision import transforms
def int_parameter(level, maxval):
"""Helper function to scale `val` between 0 and maxval .
Args:
level: Level of the operation that will be between [0, `PARAMETER_MAX`].
maxval: Maximum value that the operation can have. This will be scaled to
level/PARAMETER_MAX.
Returns:
An int that results from scaling `maxval` according to `level`.
"""
return int(level * maxval / 10)
def float_parameter(level, maxval):
"""Helper function to scale `val` between 0 and maxval.
Args:
level: Level of the operation that will be between [0, `PARAMETER_MAX`].
maxval: Maximum value that the operation can have. This will be scaled to
level/PARAMETER_MAX.
Returns:
A float that results from scaling `maxval` according to `level`.
"""
return float(level) * maxval / 10.
def sample_level(n):
return np.random.uniform(low=0.1, high=n)
def autocontrast(pil_img, _):
return ImageOps.autocontrast(pil_img)
def equalize(pil_img, _):
return ImageOps.equalize(pil_img)
def posterize(pil_img, level):
level = int_parameter(sample_level(level), 4)
return ImageOps.posterize(pil_img, 4 - level)
def rotate(pil_img, level):
degrees = int_parameter(sample_level(level), 30)
if np.random.uniform() > 0.5:
degrees = -degrees
return pil_img.rotate(degrees, resample=Image.BILINEAR)
def solarize(pil_img, level):
level = int_parameter(sample_level(level), 256)
return ImageOps.solarize(pil_img, 256 - level)
def shear_x(pil_img, level):
level = float_parameter(sample_level(level), 0.3)
if np.random.uniform() > 0.5:
level = -level
return pil_img.transform((IMAGE_SIZE, IMAGE_SIZE),
Image.AFFINE, (1, level, 0, 0, 1, 0),
resample=Image.BILINEAR)
def shear_y(pil_img, level):
level = float_parameter(sample_level(level), 0.3)
if np.random.uniform() > 0.5:
level = -level
return pil_img.transform((IMAGE_SIZE, IMAGE_SIZE),
Image.AFFINE, (1, 0, 0, level, 1, 0),
resample=Image.BILINEAR)
def translate_x(pil_img, level):
level = int_parameter(sample_level(level), IMAGE_SIZE / 3)
if np.random.random() > 0.5:
level = -level
return pil_img.transform((IMAGE_SIZE, IMAGE_SIZE),
Image.AFFINE, (1, 0, level, 0, 1, 0),
resample=Image.BILINEAR)
def translate_y(pil_img, level):
level = int_parameter(sample_level(level), IMAGE_SIZE / 3)
if np.random.random() > 0.5:
level = -level
return pil_img.transform((IMAGE_SIZE, IMAGE_SIZE),
Image.AFFINE, (1, 0, 0, 0, 1, level),
resample=Image.BILINEAR)
# operation that overlaps with ImageNet-C's test set
def color(pil_img, level):
level = float_parameter(sample_level(level), 1.8) + 0.1
return ImageEnhance.Color(pil_img).enhance(level)
# operation that overlaps with ImageNet-C's test set
def contrast(pil_img, level):
level = float_parameter(sample_level(level), 1.8) + 0.1
return ImageEnhance.Contrast(pil_img).enhance(level)
# operation that overlaps with ImageNet-C's test set
def brightness(pil_img, level):
level = float_parameter(sample_level(level), 1.8) + 0.1
return ImageEnhance.Brightness(pil_img).enhance(level)
# operation that overlaps with ImageNet-C's test set
def sharpness(pil_img, level):
level = float_parameter(sample_level(level), 1.8) + 0.1
return ImageEnhance.Sharpness(pil_img).enhance(level)
def random_resized_crop(pil_img, level):
return transforms.RandomResizedCrop(32)(pil_img)
def random_flip(pil_img, level):
return transforms.RandomHorizontalFlip(p=0.5)(pil_img)
def grayscale(pil_img, level):
return transforms.Grayscale(num_output_channels=3)(pil_img)
augmentations = [
autocontrast, equalize, posterize, rotate, solarize, shear_x, shear_y,
translate_x, translate_y, grayscale #random_resized_crop, random_flip
]
augmentations_all = [
autocontrast, equalize, posterize, rotate, solarize, shear_x, shear_y,
translate_x, translate_y, color, contrast, brightness, sharpness, grayscale #, random_resized_crop, random_flip
]
def aug_tiny(image, preprocess, mixture_width=3, mixture_depth=-1, aug_severity=3):
"""Perform AugMix augmentations and compute mixture.
Args:
image: PIL.Image input image
preprocess: Preprocessing function which should return a torch tensor.
Returns:
mixed: Augmented and mixed image.
"""
aug_list = augmentations
# if args.all_ops:
# aug_list = augmentations.augmentations_all
ws = np.float32(np.random.dirichlet([1] * mixture_width))
m = np.float32(np.random.beta(1, 1))
mix = torch.zeros_like(preprocess(image))
for i in range(mixture_width):
image_aug = image.copy()
depth = mixture_depth if mixture_depth > 0 else np.random.randint(
1, 4)
for _ in range(depth):
op = np.random.choice(aug_list)
image_aug = op(image_aug, aug_severity)
# Preprocessing commutes since all coefficients are convex
mix += ws[i] * preprocess(image_aug)
mixed = (1 - m) * preprocess(image) + m * mix
return mixed