feats: add loader in classification task datasets.

test/test_datasets.py

@@ -24,6 +24,7 @@
 import torch.nn.functional as F
 from common_utils import combinations_grid
 from torchvision import datasets
+from torchvision.io import decode_image
 from torchvision.transforms import v2
 
 
@@ -1175,6 +1176,8 @@ class SBUTestCase(datasets_utils.ImageDatasetTestCase):
     DATASET_CLASS = datasets.SBU
     FEATURE_TYPES = (PIL.Image.Image, str)
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir, config):
         num_images = 3
 
@@ -1413,6 +1416,8 @@ class Flickr8kTestCase(datasets_utils.ImageDatasetTestCase):
     _IMAGES_FOLDER = "images"
     _ANNOTATIONS_FILE = "captions.html"
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def dataset_args(self, tmpdir, config):
         tmpdir = pathlib.Path(tmpdir)
         root = tmpdir / self._IMAGES_FOLDER
@@ -1482,6 +1487,8 @@ class Flickr30kTestCase(Flickr8kTestCase):
 
     _ANNOTATIONS_FILE = "captions.token"
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def _image_file_name(self, idx):
         return f"{idx}.jpg"
 
@@ -1942,6 +1949,8 @@ class LFWPeopleTestCase(datasets_utils.DatasetTestCase):
     _IMAGES_DIR = {"original": "lfw", "funneled": "lfw_funneled", "deepfunneled": "lfw-deepfunneled"}
     _file_id = {"10fold": "", "train": "DevTrain", "test": "DevTest"}
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir, config):
         tmpdir = pathlib.Path(tmpdir) / "lfw-py"
         os.makedirs(tmpdir, exist_ok=True)
@@ -1978,6 +1987,18 @@ def _create_random_id(self):
         part2 = datasets_utils.create_random_string(random.randint(4, 7))
         return f"{part1}_{part2}"
 
+    def test_tv_decode_image_support(self):
+        if not self.SUPPORT_TV_IMAGE_DECODE:
+            pytest.skip(f"{self.DATASET_CLASS.__name__} does not support torchvision.io.decode_image.")
+
+        with self.create_dataset(
+            config=dict(
+                loader=decode_image,
+            )
+        ) as (dataset, _):
+            image = dataset[0][0]
+            assert isinstance(image, torch.Tensor)
+
 
 class LFWPairsTestCase(LFWPeopleTestCase):
     DATASET_CLASS = datasets.LFWPairs
@@ -2335,6 +2356,8 @@ class Food101TestCase(datasets_utils.ImageDatasetTestCase):
 
     ADDITIONAL_CONFIGS = combinations_grid(split=("train", "test"))
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir: str, config):
         root_folder = pathlib.Path(tmpdir) / "food-101"
         image_folder = root_folder / "images"
@@ -2371,6 +2394,7 @@ class FGVCAircraftTestCase(datasets_utils.ImageDatasetTestCase):
     ADDITIONAL_CONFIGS = combinations_grid(
         split=("train", "val", "trainval", "test"), annotation_level=("variant", "family", "manufacturer")
     )
+    SUPPORT_TV_IMAGE_DECODE = True
 
     def inject_fake_data(self, tmpdir: str, config):
         split = config["split"]
@@ -2420,6 +2444,8 @@ def inject_fake_data(self, tmpdir: str, config):
 class SUN397TestCase(datasets_utils.ImageDatasetTestCase):
     DATASET_CLASS = datasets.SUN397
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir: str, config):
         data_dir = pathlib.Path(tmpdir) / "SUN397"
         data_dir.mkdir()
@@ -2451,6 +2477,8 @@ class DTDTestCase(datasets_utils.ImageDatasetTestCase):
     DATASET_CLASS = datasets.DTD
     FEATURE_TYPES = (PIL.Image.Image, int)
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     ADDITIONAL_CONFIGS = combinations_grid(
         split=("train", "test", "val"),
         # There is no need to test the whole matrix here, since each fold is treated exactly the same
@@ -2611,6 +2639,7 @@ class CLEVRClassificationTestCase(datasets_utils.ImageDatasetTestCase):
     FEATURE_TYPES = (PIL.Image.Image, (int, type(None)))
 
     ADDITIONAL_CONFIGS = combinations_grid(split=("train", "val", "test"))
+    SUPPORT_TV_IMAGE_DECODE = True
 
     def inject_fake_data(self, tmpdir, config):
         data_folder = pathlib.Path(tmpdir) / "clevr" / "CLEVR_v1.0"
@@ -2708,6 +2737,8 @@ class StanfordCarsTestCase(datasets_utils.ImageDatasetTestCase):
     REQUIRED_PACKAGES = ("scipy",)
     ADDITIONAL_CONFIGS = combinations_grid(split=("train", "test"))
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir, config):
         import scipy.io as io
         from numpy.core.records import fromarrays
@@ -2782,6 +2813,8 @@ class Flowers102TestCase(datasets_utils.ImageDatasetTestCase):
     ADDITIONAL_CONFIGS = combinations_grid(split=("train", "val", "test"))
     REQUIRED_PACKAGES = ("scipy",)
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir: str, config):
         base_folder = pathlib.Path(tmpdir) / "flowers-102"
 
@@ -2840,6 +2873,8 @@ class RenderedSST2TestCase(datasets_utils.ImageDatasetTestCase):
     ADDITIONAL_CONFIGS = combinations_grid(split=("train", "val", "test"))
     SPLIT_TO_FOLDER = {"train": "train", "val": "valid", "test": "test"}
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     def inject_fake_data(self, tmpdir: str, config):
         root_folder = pathlib.Path(tmpdir) / "rendered-sst2"
         image_folder = root_folder / self.SPLIT_TO_FOLDER[config["split"]]
@@ -3500,6 +3535,8 @@ class ImagenetteTestCase(datasets_utils.ImageDatasetTestCase):
     DATASET_CLASS = datasets.Imagenette
     ADDITIONAL_CONFIGS = combinations_grid(split=["train", "val"], size=["full", "320px", "160px"])
 
+    SUPPORT_TV_IMAGE_DECODE = True
+
     _WNIDS = [
         "n01440764",
         "n02102040",

torchvision/datasets/clevr.py

@@ -3,7 +3,7 @@
 from typing import Any, Callable, List, Optional, Tuple, Union
 from urllib.parse import urlparse
 
-from PIL import Image
+from .folder import default_loader
 
 from .utils import download_and_extract_archive, verify_str_arg
 from .vision import VisionDataset
@@ -18,11 +18,14 @@ class CLEVRClassification(VisionDataset):
         root (str or ``pathlib.Path``): Root directory of dataset where directory ``root/clevr`` exists or will be saved to if download is
             set to True.
         split (string, optional): The dataset split, supports ``"train"`` (default), ``"val"``, or ``"test"``.
-        transform (callable, optional): A function/transform that takes in a PIL image and returns a transformed
-            version. E.g, ``transforms.RandomCrop``
+        transform (callable, optional): A function/transform that takes in a PIL image or torch.Tensor, depends on the given loader,
+            and returns a transformed version. E.g, ``transforms.RandomCrop``
         target_transform (callable, optional): A function/transform that takes in them target and transforms it.
         download (bool, optional): If true, downloads the dataset from the internet and puts it in root directory. If
             dataset is already downloaded, it is not downloaded again.
+        loader (callable, optional): A function to load an image given its path.
+            By default, it uses PIL as its image loader, but users could also pass in
+            ``torchvision.io.decode_image`` for decoding image data into tensors directly.
     """
 
     _URL = "https://dl.fbaipublicfiles.com/clevr/CLEVR_v1.0.zip"
@@ -35,9 +38,11 @@ def __init__(
         transform: Optional[Callable] = None,
         target_transform: Optional[Callable] = None,
         download: bool = False,
+        loader: Callable[[Union[str, pathlib.Path]], Any] = default_loader,
     ) -> None:
         self._split = verify_str_arg(split, "split", ("train", "val", "test"))
         super().__init__(root, transform=transform, target_transform=target_transform)
+        self.loader = loader
         self._base_folder = pathlib.Path(self.root) / "clevr"
         self._data_folder = self._base_folder / pathlib.Path(urlparse(self._URL).path).stem
 
@@ -65,7 +70,7 @@ def __getitem__(self, idx: int) -> Tuple[Any, Any]:
         image_file = self._image_files[idx]
         label = self._labels[idx]
 
-        image = Image.open(image_file).convert("RGB")
+        image = self.loader(image_file)
 
         if self.transform:
             image = self.transform(image)

torchvision/datasets/country211.py

@@ -16,8 +16,8 @@ class Country211(ImageFolder):
     Args:
         root (str or ``pathlib.Path``): Root directory of the dataset.
         split (string, optional): The dataset split, supports ``"train"`` (default), ``"valid"`` and ``"test"``.
-        transform (callable, optional): A function/transform that takes in a PIL image and returns a transformed
-            version. E.g, ``transforms.RandomCrop``.
+        transform (callable, optional): A function/transform that takes in a PIL image or torch.Tensor, depends on the given loader,
+            and returns a transformed version. E.g, ``transforms.RandomCrop``
         target_transform (callable, optional): A function/transform that takes in the target and transforms it.
         download (bool, optional): If True, downloads the dataset from the internet and puts it into
             ``root/country211/``. If dataset is already downloaded, it is not downloaded again.

torchvision/datasets/dtd.py

@@ -2,7 +2,7 @@
 import pathlib
 from typing import Any, Callable, Optional, Tuple, Union
 
-import PIL.Image
+from .folder import default_loader
 
 from .utils import download_and_extract_archive, verify_str_arg
 from .vision import VisionDataset
@@ -21,12 +21,15 @@ class DTD(VisionDataset):
                 The partition only changes which split each image belongs to. Thus, regardless of the selected
                 partition, combining all splits will result in all images.
 
-        transform (callable, optional): A function/transform that takes in a PIL image and returns a transformed
-            version. E.g, ``transforms.RandomCrop``.
+        transform (callable, optional): A function/transform that takes in a PIL image or torch.Tensor, depends on the given loader,
+            and returns a transformed version. E.g, ``transforms.RandomCrop``
         target_transform (callable, optional): A function/transform that takes in the target and transforms it.
         download (bool, optional): If True, downloads the dataset from the internet and
             puts it in root directory. If dataset is already downloaded, it is not
             downloaded again. Default is False.
+        loader (callable, optional): A function to load an image given its path.
+            By default, it uses PIL as its image loader, but users could also pass in
+            ``torchvision.io.decode_image`` for decoding image data into tensors directly.
     """
 
     _URL = "https://www.robots.ox.ac.uk/~vgg/data/dtd/download/dtd-r1.0.1.tar.gz"
@@ -40,6 +43,7 @@ def __init__(
         transform: Optional[Callable] = None,
         target_transform: Optional[Callable] = None,
         download: bool = False,
+        loader: Callable[[Union[str, pathlib.Path]], Any] = default_loader,
     ) -> None:
         self._split = verify_str_arg(split, "split", ("train", "val", "test"))
         if not isinstance(partition, int) and not (1 <= partition <= 10):
@@ -72,13 +76,14 @@ def __init__(
         self.classes = sorted(set(classes))
         self.class_to_idx = dict(zip(self.classes, range(len(self.classes))))
         self._labels = [self.class_to_idx[cls] for cls in classes]
+        self.loader = loader
 
     def __len__(self) -> int:
         return len(self._image_files)
 
     def __getitem__(self, idx: int) -> Tuple[Any, Any]:
         image_file, label = self._image_files[idx], self._labels[idx]
-        image = PIL.Image.open(image_file).convert("RGB")
+        image = self.loader(image_file)
 
         if self.transform:
             image = self.transform(image)

torchvision/datasets/eurosat.py

@@ -14,7 +14,7 @@ class EuroSAT(ImageFolder):
 
     Args:
         root (str or ``pathlib.Path``): Root directory of dataset where ``root/eurosat`` exists.
-        transform (callable, optional): A function/transform that takes in a PIL image
+        transform (callable, optional): A function/transform that takes in a PIL image or torch.Tensor, depends on the given loader,
             and returns a transformed version. E.g, ``transforms.RandomCrop``
         target_transform (callable, optional): A function/transform that takes in the
             target and transforms it.

torchvision/datasets/fgvc_aircraft.py

@@ -4,7 +4,7 @@
 from pathlib import Path
 from typing import Any, Callable, Optional, Tuple, Union
 
-import PIL.Image
+from .folder import default_loader
 
 from .utils import download_and_extract_archive, verify_str_arg
 from .vision import VisionDataset
@@ -29,13 +29,16 @@ class FGVCAircraft(VisionDataset):
             ``trainval`` and ``test``.
         annotation_level (str, optional): The annotation level, supports ``variant``,
             ``family`` and ``manufacturer``.
-        transform (callable, optional): A function/transform that takes in a PIL image
+        transform (callable, optional): A function/transform that takes in a PIL image or torch.Tensor, depends on the given loader,
             and returns a transformed version. E.g, ``transforms.RandomCrop``
         target_transform (callable, optional): A function/transform that takes in the
             target and transforms it.
         download (bool, optional): If True, downloads the dataset from the internet and
             puts it in root directory. If dataset is already downloaded, it is not
             downloaded again.
+        loader (callable, optional): A function to load an image given its path.
+            By default, it uses PIL as its image loader, but users could also pass in
+            ``torchvision.io.decode_image`` for decoding image data into tensors directly.
     """
 
     _URL = "https://www.robots.ox.ac.uk/~vgg/data/fgvc-aircraft/archives/fgvc-aircraft-2013b.tar.gz"
@@ -48,6 +51,7 @@ def __init__(
         transform: Optional[Callable] = None,
         target_transform: Optional[Callable] = None,
         download: bool = False,
+        loader: Callable[[str], Any] = default_loader,
     ) -> None:
         super().__init__(root, transform=transform, target_transform=target_transform)
         self._split = verify_str_arg(split, "split", ("train", "val", "trainval", "test"))
@@ -87,13 +91,14 @@ def __init__(
                 image_name, label_name = line.strip().split(" ", 1)
                 self._image_files.append(os.path.join(image_data_folder, f"{image_name}.jpg"))
                 self._labels.append(self.class_to_idx[label_name])
+        self.loader = loader
 
     def __len__(self) -> int:
         return len(self._image_files)
 
     def __getitem__(self, idx: int) -> Tuple[Any, Any]:
         image_file, label = self._image_files[idx], self._labels[idx]
-        image = PIL.Image.open(image_file).convert("RGB")
+        image = self.loader(image_file)
 
         if self.transform:
             image = self.transform(image)