mmclassification/mmcls/datasets/custom.py

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# Copyright (c) OpenMMLab. All rights reserved.
import warnings
from typing import Callable, Dict, List, Optional, Sequence, Tuple, Union
import mmcv
import numpy as np
from mmcv import FileClient
from .base_dataset import BaseDataset
from .builder import DATASETS
def find_folders(root: str,
file_client: FileClient) -> Tuple[List[str], Dict[str, int]]:
"""Find classes by folders under a root.
Args:
root (string): root directory of folders
Returns:
Tuple[List[str], Dict[str, int]]:
- folders: The name of sub folders under the root.
- folder_to_idx: The map from folder name to class idx.
"""
folders = list(
file_client.list_dir_or_file(
root,
list_dir=True,
list_file=False,
recursive=False,
))
folders.sort()
folder_to_idx = {folders[i]: i for i in range(len(folders))}
return folders, folder_to_idx
def get_samples(root: str, folder_to_idx: Dict[str, int],
is_valid_file: Callable, file_client: FileClient):
"""Make dataset by walking all images under a root.
Args:
root (string): root directory of folders
folder_to_idx (dict): the map from class name to class idx
is_valid_file (Callable): A function that takes path of a file
and check if the file is a valid sample file.
Returns:
Tuple[list, set]:
- samples: a list of tuple where each element is (image, class_idx)
- empty_folders: The folders don't have any valid files.
"""
samples = []
available_classes = set()
for folder_name in sorted(list(folder_to_idx.keys())):
_dir = file_client.join_path(root, folder_name)
files = list(
file_client.list_dir_or_file(
_dir,
list_dir=False,
list_file=True,
recursive=True,
))
for file in sorted(list(files)):
if is_valid_file(file):
path = file_client.join_path(folder_name, file)
item = (path, folder_to_idx[folder_name])
samples.append(item)
available_classes.add(folder_name)
empty_folders = set(folder_to_idx.keys()) - available_classes
return samples, empty_folders
@DATASETS.register_module()
class CustomDataset(BaseDataset):
"""Custom dataset for classification.
The dataset supports two kinds of annotation format.
1. An annotation file is provided, and each line indicates a sample:
The sample files: ::
data_prefix/
folder_1
xxx.png
xxy.png
...
folder_2
123.png
nsdf3.png
...
The annotation file (the first column is the image path and the second
column is the index of category): ::
folder_1/xxx.png 0
folder_1/xxy.png 1
folder_2/123.png 5
folder_2/nsdf3.png 3
...
Please specify the name of categories by the argument ``classes``.
2. The samples are arranged in the specific way: ::
data_prefix/
class_x
xxx.png
xxy.png
...
xxz.png
class_y
123.png
nsdf3.png
...
asd932_.png
If the ``ann_file`` is specified, the dataset will be generated by the
first way, otherwise, try the second way.
Args:
data_prefix (str): The path of data directory.
pipeline (Sequence[dict]): A list of dict, where each element
represents a operation defined in :mod:`mmcls.datasets.pipelines`.
Defaults to an empty tuple.
classes (str | Sequence[str], optional): Specify names of classes.
- If is string, it should be a file path, and the every line of
the file is a name of a class.
- If is a sequence of string, every item is a name of class.
- If is None, use ``cls.CLASSES`` or the names of sub folders
(If use the second way to arrange samples).
Defaults to None.
ann_file (str, optional): The annotation file. If is string, read
samples paths from the ann_file. If is None, find samples in
``data_prefix``. Defaults to None.
extensions (Sequence[str]): A sequence of allowed extensions. Defaults
to ('.jpg', '.jpeg', '.png', '.ppm', '.bmp', '.pgm', '.tif').
test_mode (bool): In train mode or test mode. It's only a mark and
won't be used in this class. Defaults to False.
file_client_args (dict, optional): Arguments to instantiate a
FileClient. See :class:`mmcv.fileio.FileClient` for details.
If None, automatically inference from the specified path.
Defaults to None.
"""
def __init__(self,
data_prefix: str,
pipeline: Sequence = (),
classes: Union[str, Sequence[str], None] = None,
ann_file: Optional[str] = None,
extensions: Sequence[str] = ('.jpg', '.jpeg', '.png', '.ppm',
'.bmp', '.pgm', '.tif'),
test_mode: bool = False,
file_client_args: Optional[dict] = None):
self.extensions = tuple(set([i.lower() for i in extensions]))
self.file_client_args = file_client_args
super().__init__(
data_prefix=data_prefix,
pipeline=pipeline,
classes=classes,
ann_file=ann_file,
test_mode=test_mode)
def _find_samples(self):
"""find samples from ``data_prefix``."""
file_client = FileClient.infer_client(self.file_client_args,
self.data_prefix)
classes, folder_to_idx = find_folders(self.data_prefix, file_client)
samples, empty_classes = get_samples(
self.data_prefix,
folder_to_idx,
is_valid_file=self.is_valid_file,
file_client=file_client,
)
if len(samples) == 0:
raise RuntimeError(
f'Found 0 files in subfolders of: {self.data_prefix}. '
f'Supported extensions are: {",".join(self.extensions)}')
if self.CLASSES is not None:
assert len(self.CLASSES) == len(classes), \
f"The number of subfolders ({len(classes)}) doesn't match " \
f'the number of specified classes ({len(self.CLASSES)}). ' \
'Please check the data folder.'
else:
self.CLASSES = classes
if empty_classes:
warnings.warn(
'Found no valid file in the folder '
f'{", ".join(empty_classes)}. '
f"Supported extensions are: {', '.join(self.extensions)}",
UserWarning)
self.folder_to_idx = folder_to_idx
return samples
def load_annotations(self):
"""Load image paths and gt_labels."""
if self.ann_file is None:
samples = self._find_samples()
elif isinstance(self.ann_file, str):
lines = mmcv.list_from_file(
self.ann_file, file_client_args=self.file_client_args)
samples = [x.strip().rsplit(' ', 1) for x in lines]
else:
raise TypeError('ann_file must be a str or None')
data_infos = []
for filename, gt_label in samples:
info = {'img_prefix': self.data_prefix}
info['img_info'] = {'filename': filename}
info['gt_label'] = np.array(gt_label, dtype=np.int64)
data_infos.append(info)
return data_infos
def is_valid_file(self, filename: str) -> bool:
"""Check if a file is a valid sample."""
return filename.lower().endswith(self.extensions)