simplify loading RGBA images

CHANGELOG.md

@@ -14,6 +14,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Changed `Postprocess` to `OutputTransform` ([#942](https://github.com/PyTorchLightning/lightning-flash/pull/942))
 
+- Changed loading of RGBA images to drop alpha channel by default ([#946](https://github.com/PyTorchLightning/lightning-flash/pull/946))
+
 ### Deprecated
 
 - Deprecated `flash.core.data.process.Serializer` in favour of `flash.core.data.io.output.Output` ([#927](https://github.com/PyTorchLightning/lightning-flash/pull/927))

flash/audio/classification/data.py

@@ -25,17 +25,14 @@
     PathsDataSource,
 )
 from flash.core.data.process import Deserializer, Preprocess
-from flash.core.utilities.imports import _TORCHVISION_AVAILABLE
+from flash.core.data.utils import image_default_loader
 from flash.image.classification.data import ImageClassificationData
 from flash.image.data import ImageDeserializer, IMG_EXTENSIONS, NP_EXTENSIONS
 
-if _TORCHVISION_AVAILABLE:
-    from torchvision.datasets.folder import default_loader
-
 
 def spectrogram_loader(filepath: str):
     if has_file_allowed_extension(filepath, IMG_EXTENSIONS):
-        img = default_loader(filepath)
+        img = image_default_loader(filepath)
         data = np.array(img)
     else:
         data = np.load(filepath)

flash/core/data/utils.py

@@ -23,8 +23,17 @@
 from torch import Tensor
 from tqdm.auto import tqdm as tq
 
+from flash.core.utilities.imports import _PIL_AVAILABLE, _TORCHVISION_AVAILABLE
 from flash.core.utilities.stages import RunningStage
 
+if _PIL_AVAILABLE:
+    from PIL.Image import Image
+else:
+    Image = object
+
+if _TORCHVISION_AVAILABLE:
+    from torchvision.datasets.folder import default_loader
+
 _STAGES_PREFIX = {
     RunningStage.TRAINING: "train",
     RunningStage.TESTING: "test",
@@ -207,3 +216,16 @@ def convert_to_modules(transforms: Optional[Dict[str, Callable]]):
         transforms, Iterable, torch.nn.ModuleList, wrong_dtype=(torch.nn.ModuleList, torch.nn.ModuleDict)
     )
     return transforms
+
+
+def image_default_loader(file_path: str, drop_alpha: bool = True) -> Image:
+    """Default loader for images.
+
+    Args:
+        file_path: The image file to load.
+        drop_alpha: If ``True`` (default) then any alpha channels will be silently removed.
+    """
+    img = default_loader(file_path)
+    if img.mode == "RGBA" and drop_alpha:
+        img = img.convert("RGB")
+    return img

flash/core/integrations/labelstudio/data_source.py

@@ -8,12 +8,10 @@
 
 from flash.core.data.auto_dataset import AutoDataset, IterableAutoDataset
 from flash.core.data.data_source import DataSource, DefaultDataKeys, has_len
-from flash.core.utilities.imports import _PYTORCHVIDEO_AVAILABLE, _TEXT_AVAILABLE, _TORCHVISION_AVAILABLE
+from flash.core.data.utils import image_default_loader
+from flash.core.utilities.imports import _PYTORCHVIDEO_AVAILABLE, _TEXT_AVAILABLE
 from flash.core.utilities.stages import RunningStage
 
-if _TORCHVISION_AVAILABLE:
-    from torchvision.datasets.folder import default_loader
-
 if _TEXT_AVAILABLE:
     from transformers import AutoTokenizer
 
@@ -188,7 +186,7 @@ def load_sample(self, sample: Mapping[str, Any] = None, dataset: Optional[Any] =
         """Load 1 sample from dataset."""
         p = sample["file_upload"]
         # loading image
-        image = default_loader(p)
+        image = image_default_loader(p)
         result = {DefaultDataKeys.INPUT: image, DefaultDataKeys.TARGET: self._get_labels_from_sample(sample["label"])}
         return result
 

flash/image/data.py

@@ -30,10 +30,11 @@
     TensorDataSource,
 )
 from flash.core.data.process import Deserializer
+from flash.core.data.utils import image_default_loader
 from flash.core.utilities.imports import _TORCHVISION_AVAILABLE, Image, requires
 
 if _TORCHVISION_AVAILABLE:
-    from torchvision.datasets.folder import default_loader, IMG_EXTENSIONS
+    from torchvision.datasets.folder import IMG_EXTENSIONS
     from torchvision.transforms.functional import to_pil_image
 else:
     IMG_EXTENSIONS = (".jpg", ".jpeg", ".png", ".ppm", ".bmp", ".pgm", ".tif", ".tiff", ".webp")
@@ -44,7 +45,7 @@
 
 def image_loader(filepath: str):
     if has_file_allowed_extension(filepath, IMG_EXTENSIONS):
-        img = default_loader(filepath)
+        img = image_default_loader(filepath)
     elif has_file_allowed_extension(filepath, NP_EXTENSIONS):
         img = Image.fromarray(np.load(filepath).astype("uint8"), "RGB")
     else:
@@ -116,7 +117,7 @@ class ImageFiftyOneDataSource(FiftyOneDataSource):
     @staticmethod
     def load_sample(sample: Dict[str, Any], dataset: Optional[Any] = None) -> Dict[str, Any]:
         img_path = sample[DefaultDataKeys.INPUT]
-        img = default_loader(img_path)
+        img = image_default_loader(img_path)
         sample[DefaultDataKeys.INPUT] = img
         w, h = img.size  # WxH
         sample[DefaultDataKeys.METADATA] = {

flash/image/face_detection/data.py

@@ -21,13 +21,13 @@
 from flash.core.data.io.output_transform import OutputTransform
 from flash.core.data.process import Preprocess
 from flash.core.data.transforms import ApplyToKeys
+from flash.core.data.utils import image_default_loader
 from flash.core.utilities.imports import _FASTFACE_AVAILABLE, _TORCHVISION_AVAILABLE
 from flash.image.data import ImagePathsDataSource
 from flash.image.detection import ObjectDetectionData
 
 if _TORCHVISION_AVAILABLE:
     import torchvision
-    from torchvision.datasets.folder import default_loader
 
 if _FASTFACE_AVAILABLE:
     import fastface as ff
@@ -86,7 +86,7 @@ def load_data(self, data: Dataset, dataset: Any = None) -> Dataset:
 
     def load_sample(self, sample: Any, dataset: Optional[Any] = None) -> Mapping[str, Any]:
         filepath = sample[DefaultDataKeys.INPUT]
-        img = default_loader(filepath)
+        img = image_default_loader(filepath)
         sample[DefaultDataKeys.INPUT] = img
 
         w, h = img.size  # WxH

flash/image/segmentation/data.py

@@ -34,6 +34,7 @@
     TensorDataSource,
 )
 from flash.core.data.process import Deserializer, Preprocess
+from flash.core.data.utils import image_default_loader
 from flash.core.utilities.imports import (
     _FIFTYONE_AVAILABLE,
     _MATPLOTLIB_AVAILABLE,
@@ -63,7 +64,7 @@
 if _TORCHVISION_AVAILABLE:
     import torchvision
     import torchvision.transforms.functional as FT
-    from torchvision.datasets.folder import default_loader, has_file_allowed_extension
+    from torchvision.datasets.folder import has_file_allowed_extension
 
 
 class SemanticSegmentationNumpyDataSource(NumpyDataSource):
@@ -138,7 +139,7 @@ def load_sample(self, sample: Mapping[str, Any]) -> Mapping[str, Union[torch.Ten
         img_labels_path = sample[DefaultDataKeys.TARGET]
 
         # load images directly to torch tensors
-        img: torch.Tensor = FT.to_tensor(default_loader(img_path))  # CxHxW
+        img: torch.Tensor = FT.to_tensor(image_default_loader(img_path))  # CxHxW
         img_labels: torch.Tensor = torchvision.io.read_image(img_labels_path)  # CxHxW
         img_labels = img_labels[0]  # HxW
 
@@ -153,7 +154,7 @@ def load_sample(self, sample: Mapping[str, Any]) -> Mapping[str, Union[torch.Ten
     @staticmethod
     def predict_load_sample(sample: Mapping[str, Any]) -> Mapping[str, Any]:
         img_path = sample[DefaultDataKeys.INPUT]
-        img = FT.to_tensor(default_loader(img_path)).float()
+        img = FT.to_tensor(image_default_loader(img_path)).float()
 
         sample[DefaultDataKeys.INPUT] = img
         sample[DefaultDataKeys.METADATA] = {
@@ -184,7 +185,7 @@ def load_sample(self, sample: Mapping[str, str]) -> Mapping[str, Union[torch.Ten
         img_path = sample[DefaultDataKeys.INPUT]
         fo_sample = _fo_dataset[img_path]
 
-        img: torch.Tensor = FT.to_tensor(default_loader(img_path))  # CxHxW
+        img: torch.Tensor = FT.to_tensor(image_default_loader(img_path))  # CxHxW
         img_labels: torch.Tensor = torch.from_numpy(fo_sample[self.label_field].mask)  # HxW
 
         sample[DefaultDataKeys.INPUT] = img.float()
@@ -198,7 +199,7 @@ def load_sample(self, sample: Mapping[str, str]) -> Mapping[str, Union[torch.Ten
     @staticmethod
     def predict_load_sample(sample: Mapping[str, Any]) -> Mapping[str, Any]:
         img_path = sample[DefaultDataKeys.INPUT]
-        img = FT.to_tensor(default_loader(img_path)).float()
+        img = FT.to_tensor(image_default_loader(img_path)).float()
 
         sample[DefaultDataKeys.INPUT] = img
         sample[DefaultDataKeys.METADATA] = {