Spaces:
Running
Running
File size: 5,930 Bytes
4a4ed11 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 |
import math
import random
from PIL import Image
import blobfile as bf
from mpi4py import MPI
import numpy as np
from torch.utils.data import DataLoader, Dataset
def load_data(
*,
data_dir,
batch_size,
image_size,
class_cond=False,
deterministic=False,
random_crop=False,
random_flip=True,
):
"""
For a dataset, create a generator over (images, kwargs) pairs.
Each images is an NCHW float tensor, and the kwargs dict contains zero or
more keys, each of which map to a batched Tensor of their own.
The kwargs dict can be used for class labels, in which case the key is "y"
and the values are integer tensors of class labels.
:param data_dir: a dataset directory.
:param batch_size: the batch size of each returned pair.
:param image_size: the size to which images are resized.
:param class_cond: if True, include a "y" key in returned dicts for class
label. If classes are not available and this is true, an
exception will be raised.
:param deterministic: if True, yield results in a deterministic order.
:param random_crop: if True, randomly crop the images for augmentation.
:param random_flip: if True, randomly flip the images for augmentation.
"""
if not data_dir:
raise ValueError("unspecified data directory")
all_files = _list_image_files_recursively(data_dir)
classes = None
if class_cond:
# Assume classes are the first part of the filename,
# before an underscore.
class_names = [bf.basename(path).split("_")[0] for path in all_files]
sorted_classes = {x: i for i, x in enumerate(sorted(set(class_names)))}
classes = [sorted_classes[x] for x in class_names]
dataset = ImageDataset(
image_size,
all_files,
classes=classes,
shard=MPI.COMM_WORLD.Get_rank(),
num_shards=MPI.COMM_WORLD.Get_size(),
random_crop=random_crop,
random_flip=random_flip,
)
if deterministic:
loader = DataLoader(
dataset, batch_size=batch_size, shuffle=False, num_workers=1, drop_last=True
)
else:
loader = DataLoader(
dataset, batch_size=batch_size, shuffle=True, num_workers=1, drop_last=True
)
while True:
yield from loader
def _list_image_files_recursively(data_dir):
results = []
for entry in sorted(bf.listdir(data_dir)):
full_path = bf.join(data_dir, entry)
ext = entry.split(".")[-1]
if "." in entry and ext.lower() in ["jpg", "jpeg", "png", "gif"]:
results.append(full_path)
elif bf.isdir(full_path):
results.extend(_list_image_files_recursively(full_path))
return results
class ImageDataset(Dataset):
def __init__(
self,
resolution,
image_paths,
classes=None,
shard=0,
num_shards=1,
random_crop=False,
random_flip=True,
):
super().__init__()
self.resolution = resolution
self.local_images = image_paths[shard:][::num_shards]
self.local_classes = None if classes is None else classes[shard:][::num_shards]
self.random_crop = random_crop
self.random_flip = random_flip
def __len__(self):
return len(self.local_images)
def __getitem__(self, idx):
path = self.local_images[idx]
with bf.BlobFile(path, "rb") as f:
pil_image = Image.open(f)
pil_image.load()
pil_image = pil_image.convert("RGB")
if self.random_crop:
arr = random_crop_arr(pil_image, self.resolution)
else:
arr = center_crop_arr(pil_image, self.resolution)
if self.random_flip and random.random() < 0.5:
arr = arr[:, ::-1]
arr = arr.astype(np.float32) / 127.5 - 1
out_dict = {}
if self.local_classes is not None:
out_dict["y"] = np.array(self.local_classes[idx], dtype=np.int64)
return np.transpose(arr, [2, 0, 1]), out_dict
def center_crop_arr(pil_image, image_size):
# We are not on a new enough PIL to support the `reducing_gap`
# argument, which uses BOX downsampling at powers of two first.
# Thus, we do it by hand to improve downsample quality.
while min(*pil_image.size) >= 2 * image_size:
pil_image = pil_image.resize(
tuple(x // 2 for x in pil_image.size), resample=Image.BOX
)
scale = image_size / min(*pil_image.size)
pil_image = pil_image.resize(
tuple(round(x * scale) for x in pil_image.size), resample=Image.BICUBIC
)
arr = np.array(pil_image)
crop_y = (arr.shape[0] - image_size) // 2
crop_x = (arr.shape[1] - image_size) // 2
return arr[crop_y : crop_y + image_size, crop_x : crop_x + image_size]
def random_crop_arr(pil_image, image_size, min_crop_frac=0.8, max_crop_frac=1.0):
min_smaller_dim_size = math.ceil(image_size / max_crop_frac)
max_smaller_dim_size = math.ceil(image_size / min_crop_frac)
smaller_dim_size = random.randrange(min_smaller_dim_size, max_smaller_dim_size + 1)
# We are not on a new enough PIL to support the `reducing_gap`
# argument, which uses BOX downsampling at powers of two first.
# Thus, we do it by hand to improve downsample quality.
while min(*pil_image.size) >= 2 * smaller_dim_size:
pil_image = pil_image.resize(
tuple(x // 2 for x in pil_image.size), resample=Image.BOX
)
scale = smaller_dim_size / min(*pil_image.size)
pil_image = pil_image.resize(
tuple(round(x * scale) for x in pil_image.size), resample=Image.BICUBIC
)
arr = np.array(pil_image)
crop_y = random.randrange(arr.shape[0] - image_size + 1)
crop_x = random.randrange(arr.shape[1] - image_size + 1)
return arr[crop_y : crop_y + image_size, crop_x : crop_x + image_size]
|