# Ultralytics YOLO 🚀, AGPL-3.0 license
import contextlib
from itertools import repeat
from multiprocessing.pool import ThreadPool
from pathlib import Path
import cv2
import numpy as np
import torch
import torchvision
from ultralytics.utils import LOCAL_RANK, NUM_THREADS, TQDM, colorstr, is_dir_writeable
from .augment import Compose, Format, Instances, LetterBox, classify_albumentations, classify_transforms, v8_transforms
from .base import BaseDataset
from .utils import HELP_URL, LOGGER, get_hash, img2label_paths, verify_image, verify_image_label
# Ultralytics dataset *.cache version, >= 1.0.0 for YOLOv8
DATASET_CACHE_VERSION = '1.0.3'
class YOLODataset(BaseDataset):
"""
Dataset class for loading object detection and/or segmentation labels in YOLO format.
Args:
data (dict, optional): A dataset YAML dictionary. Defaults to None.
use_segments (bool, optional): If True, segmentation masks are used as labels. Defaults to False.
use_keypoints (bool, optional): If True, keypoints are used as labels. Defaults to False.
Returns:
(torch.utils.data.Dataset): A PyTorch dataset object that can be used for training an object detection model.
"""
def __init__(self, *args, data=None, use_segments=False, use_keypoints=False, **kwargs):
"""Initializes the YOLODataset with optional configurations for segments and keypoints."""
self.use_segments = use_segments
self.use_keypoints = use_keypoints
self.data = data
assert not (self.use_segments and self.use_keypoints), 'Can not use both segments and keypoints.'
super().__init__(*args, **kwargs)
def cache_labels(self, path=Path('./labels.cache')):
"""
Cache dataset labels, check images and read shapes.
Args:
path (Path): path where to save the cache file (default: Path('./labels.cache')).
Returns:
(dict): labels.
"""
x = {'labels': []}
nm, nf, ne, nc, msgs = 0, 0, 0, 0, [] # number missing, found, empty, corrupt, messages
desc = f'{self.prefix}Scanning {path.parent / path.stem}...'
total = len(self.im_files)
nkpt, ndim = self.data.get('kpt_shape', (0, 0))
if self.use_keypoints and (nkpt <= 0 or ndim not in (2, 3)):
raise ValueError("'kpt_shape' in data.yaml missing or incorrect. Should be a list with [number of "
"keypoints, number of dims (2 for x,y or 3 for x,y,visible)], i.e. 'kpt_shape: [17, 3]'")
with ThreadPool(NUM_THREADS) as pool:
results = pool.imap(func=verify_image_label,
iterable=zip(self.im_files, self.label_files, repeat(self.prefix),
repeat(self.use_keypoints), repeat(len(self.data['names'])), repeat(nkpt),
repeat(ndim)))
pbar = TQDM(results, desc=desc, total=total)
for im_file, lb, shape, segments, keypoint, nm_f, nf_f, ne_f, nc_f, msg in pbar:
nm += nm_f
nf += nf_f
ne += ne_f
nc += nc_f
if im_file:
x['labels'].append(
dict(
im_file=im_file,
shape=shape,
cls=lb[:, 0:1], # n, 1
bboxes=lb[:, 1:], # n, 4
segments=segments,
keypoints=keypoint,
normalized=True,
bbox_format='xywh'))
if msg:
msgs.append(msg)
pbar.desc = f'{desc} {nf} images, {nm + ne} backgrounds, {nc} corrupt'
pbar.close()
if msgs:
LOGGER.info('\n'.join(msgs))
if nf == 0:
LOGGER.warning(f'{self.prefix}WARNING ⚠️ No labels found in {path}. {HELP_URL}')
x['hash'] = get_hash(self.label_files + self.im_files)
x['results'] = nf, nm, ne, nc, len(self.im_files)
x['msgs'] = msgs # warnings
save_dataset_cache_file(self.prefix, path, x)
return x
def get_labels(self):
"""Returns dictionary of labels for YOLO training."""
self.label_files = img2label_paths(self.im_files)
cache_path = Path(self.label_files[0]).parent.with_suffix('.cache')
try:
cache, exists = load_dataset_cache_file(cache_path), True # attempt to load a *.cache file
assert cache['version'] == DATASET_CACHE_VERSION # matches current version
assert cache['hash'] == get_hash(self.label_files + self.im_files) # identical hash
except (FileNotFoundError, AssertionError, AttributeError):
cache, exists = self.cache_labels(cache_path), False # run cache ops
# Display cache
nf, nm, ne, nc, n = cache.pop('results') # found, missing, empty, corrupt, total
if exists and LOCAL_RANK in (-1, 0):
d = f'Scanning {cache_path}... {nf} images, {nm + ne} backgrounds, {nc} corrupt'
TQDM(None, desc=self.prefix + d, total=n, initial=n) # display results
if cache['msgs']:
LOGGER.info('\n'.join(cache['msgs'])) # display warnings
# Read cache
[cache.pop(k) for k in ('hash', 'version', 'msgs')] # remove items
labels = cache['labels']
if not labels:
LOGGER.warning(f'WARNING ⚠️ No images found in {cache_path}, training may not work correctly. {HELP_URL}')
self.im_files = [lb['im_file'] for lb in labels] # update im_files
# Check if the dataset is all boxes or all segments
lengths = ((len(lb['cls']), len(lb['bboxes']), len(lb['segments'])) for lb in labels)
len_cls, len_boxes, len_segments = (sum(x) for x in zip(*lengths))
if len_segments and len_boxes != len_segments:
LOGGER.warning(
f'WARNING ⚠️ Box and segment counts should be equal, but got len(segments) = {len_segments}, '
f'len(boxes) = {len_boxes}. To resolve this only boxes will be used and all segments will be removed. '
'To avoid this please supply either a detect or segment dataset, not a detect-segment mixed dataset.')
for lb in labels:
lb['segments'] = []
if len_cls == 0:
LOGGER.warning(f'WARNING ⚠️ No labels found in {cache_path}, training may not work correctly. {HELP_URL}')
return labels
def build_transforms(self, hyp=None):
"""Builds and appends transforms to the list."""
if self.augment:
hyp.mosaic = hyp.mosaic if self.augment and not self.rect else 0.0
hyp.mixup = hyp.mixup if self.augment and not self.rect else 0.0
transforms = v8_transforms(self, self.imgsz, hyp)
else:
transforms = Compose([LetterBox(new_shape=(self.imgsz, self.imgsz), scaleup=False)])
transforms.append(
Format(bbox_format='xywh',
normalize=True,
return_mask=self.use_segments,
return_keypoint=self.use_keypoints,
batch_idx=True,
mask_ratio=hyp.mask_ratio,
mask_overlap=hyp.overlap_mask))
return transforms
def close_mosaic(self, hyp):
"""Sets mosaic, copy_paste and mixup options to 0.0 and builds transformations."""
hyp.mosaic = 0.0 # set mosaic ratio=0.0
hyp.copy_paste = 0.0 # keep the same behavior as previous v8 close-mosaic
hyp.mixup = 0.0 # keep the same behavior as previous v8 close-mosaic
self.transforms = self.build_transforms(hyp)
def update_labels_info(self, label):
"""Custom your label format here."""
# NOTE: cls is not with bboxes now, classification and semantic segmentation need an independent cls label
# We can make it also support classification and semantic segmentation by add or remove some dict keys there.
bboxes = label.pop('bboxes')
segments = label.pop('segments')
keypoints = label.pop('keypoints', None)
bbox_format = label.pop('bbox_format')
normalized = label.pop('normalized')
label['instances'] = Instances(bboxes, segments, keypoints, bbox_format=bbox_format, normalized=normalized)
return label
@staticmethod
def collate_fn(batch):
"""Collates data samples into batches."""
new_batch = {}
keys = batch[0].keys()
values = list(zip(*[list(b.values()) for b in batch]))
for i, k in enumerate(keys):
value = values[i]
if k == 'img':
value = torch.stack(value, 0)
if k in ['masks', 'keypoints', 'bboxes', 'cls']:
value = torch.cat(value, 0)
new_batch[k] = value
new_batch['batch_idx'] = list(new_batch['batch_idx'])
for i in range(len(new_batch['batch_idx'])):
new_batch['batch_idx'][i] += i # add target image index for build_targets()
new_batch['batch_idx'] = torch.cat(new_batch['batch_idx'], 0)
return new_batch
# Classification dataloaders -------------------------------------------------------------------------------------------
class ClassificationDataset(torchvision.datasets.ImageFolder):
"""
YOLO Classification Dataset.
Args:
root (str): Dataset path.
Attributes:
cache_ram (bool): True if images should be cached in RAM, False otherwise.
cache_disk (bool): True if images should be cached on disk, False otherwise.
samples (list): List of samples containing file, index, npy, and im.
torch_transforms (callable): torchvision transforms applied to the dataset.
album_transforms (callable, optional): Albumentations transforms applied to the dataset if augment is True.
"""
def __init__(self, root, args, augment=False, cache=False, prefix=''):
"""
Initialize YOLO object with root, image size, augmentations, and cache settings.
Args:
root (str): Dataset path.
args (Namespace): Argument parser containing dataset related settings.
augment (bool, optional): True if dataset should be augmented, False otherwise. Defaults to False.
cache (bool | str | optional): Cache setting, can be True, False, 'ram' or 'disk'. Defaults to False.
"""
super().__init__(root=root)
if augment and args.fraction < 1.0: # reduce training fraction
self.samples = self.samples[:round(len(self.samples) * args.fraction)]
self.prefix = colorstr(f'{prefix}: ') if prefix else ''
self.cache_ram = cache is True or cache == 'ram'
self.cache_disk = cache == 'disk'
self.samples = self.verify_images() # filter out bad images
self.samples = [list(x) + [Path(x[0]).with_suffix('.npy'), None] for x in self.samples] # file, index, npy, im
self.torch_transforms = classify_transforms(args.imgsz, rect=args.rect)
self.album_transforms = classify_albumentations(
augment=augment,
size=args.imgsz,
scale=(1.0 - args.scale, 1.0), # (0.08, 1.0)
hflip=args.fliplr,
vflip=args.flipud,
hsv_h=args.hsv_h, # HSV-Hue augmentation (fraction)
hsv_s=args.hsv_s, # HSV-Saturation augmentation (fraction)
hsv_v=args.hsv_v, # HSV-Value augmentation (fraction)
mean=(0.0, 0.0, 0.0), # IMAGENET_MEAN
std=(1.0, 1.0, 1.0), # IMAGENET_STD
auto_aug=False) if augment else None
def __getitem__(self, i):
"""Returns subset of data and targets corresponding to given indices."""
f, j, fn, im = self.samples[i] # filename, index, filename.with_suffix('.npy'), image
if self.cache_ram and im is None:
im = self.samples[i][3] = cv2.imread(f)
elif self.cache_disk:
if not fn.exists(): # load npy
np.save(fn.as_posix(), cv2.imread(f), allow_pickle=False)
im = np.load(fn)
else: # read image
im = cv2.imread(f) # BGR
if self.album_transforms:
sample = self.album_transforms(image=cv2.cvtColor(im, cv2.COLOR_BGR2RGB))['image']
else:
sample = self.torch_transforms(im)
return {'img': sample, 'cls': j}
def __len__(self) -> int:
"""Return the total number of samples in the dataset."""
return len(self.samples)
def verify_images(self):
"""Verify all images in dataset."""
desc = f'{self.prefix}Scanning {self.root}...'
path = Path(self.root).with_suffix('.cache') # *.cache file path
with contextlib.suppress(FileNotFoundError, AssertionError, AttributeError):
cache = load_dataset_cache_file(path) # attempt to load a *.cache file
assert cache['version'] == DATASET_CACHE_VERSION # matches current version
assert cache['hash'] == get_hash([x[0] for x in self.samples]) # identical hash
nf, nc, n, samples = cache.pop('results') # found, missing, empty, corrupt, total
if LOCAL_RANK in (-1, 0):
d = f'{desc} {nf} images, {nc} corrupt'
TQDM(None, desc=d, total=n, initial=n)
if cache['msgs']:
LOGGER.info('\n'.join(cache['msgs'])) # display warnings
return samples
# Run scan if *.cache retrieval failed
nf, nc, msgs, samples, x = 0, 0, [], [], {}
with ThreadPool(NUM_THREADS) as pool:
results = pool.imap(func=verify_image, iterable=zip(self.samples, repeat(self.prefix)))
pbar = TQDM(results, desc=desc, total=len(self.samples))
for sample, nf_f, nc_f, msg in pbar:
if nf_f:
samples.append(sample)
if msg:
msgs.append(msg)
nf += nf_f
nc += nc_f
pbar.desc = f'{desc} {nf} images, {nc} corrupt'
pbar.close()
if msgs:
LOGGER.info('\n'.join(msgs))
x['hash'] = get_hash([x[0] for x in self.samples])
x['results'] = nf, nc, len(samples), samples
x['msgs'] = msgs # warnings
save_dataset_cache_file(self.prefix, path, x)
return samples
def load_dataset_cache_file(path):
"""Load an Ultralytics *.cache dictionary from path."""
import gc
gc.disable() # reduce pickle load time https://github.com/ultralytics/ultralytics/pull/1585
cache = np.load(str(path), allow_pickle=True).item() # load dict
gc.enable()
return cache
def save_dataset_cache_file(prefix, path, x):
"""Save an Ultralytics dataset *.cache dictionary x to path."""
x['version'] = DATASET_CACHE_VERSION # add cache version
if is_dir_writeable(path.parent):
if path.exists():
path.unlink() # remove *.cache file if exists
np.save(str(path), x) # save cache for next time
path.with_suffix('.cache.npy').rename(path) # remove .npy suffix
LOGGER.info(f'{prefix}New cache created: {path}')
else:
LOGGER.warning(f'{prefix}WARNING ⚠️ Cache directory {path.parent} is not writeable, cache not saved.')
# TODO: support semantic segmentation
class SemanticDataset(BaseDataset):
"""
Semantic Segmentation Dataset.
This class is responsible for handling datasets used for semantic segmentation tasks. It inherits functionalities
from the BaseDataset class.
Note:
This class is currently a placeholder and needs to be populated with methods and attributes for supporting
semantic segmentation tasks.
"""
def __init__(self):
"""Initialize a SemanticDataset object."""
super().__init__()