[Fix] LoadImageFromFile

mmcv/transforms/loading.py

 # Copyright (c) OpenMMLab. All rights reserved.
+from typing import Optional
+
 import numpy as np
 
 import mmcv
@@ -33,22 +35,24 @@ class LoadImageFromFile(BaseTransform):
         file_client_args (dict): Arguments to instantiate a FileClient.
             See :class:`mmcv.fileio.FileClient` for details.
             Defaults to ``dict(backend='disk')``.
+        ignore_empty (bool): Whether to allow loading empty image or file path
+            not existent. Defaults to False.
     """
 
-    def __init__(
-        self,
+    def __init__(self,
                  to_float32: bool = False,
                  color_type: str = 'color',
                  imdecode_backend: str = 'cv2',
-        file_client_args: dict = dict(backend='disk')
-    ) -> None:
+                 file_client_args: dict = dict(backend='disk'),
+                 ignore_empty: bool = False) -> None:
+        self.ignore_empty = ignore_empty
         self.to_float32 = to_float32
         self.color_type = color_type
         self.imdecode_backend = imdecode_backend
         self.file_client_args = file_client_args.copy()
         self.file_client = mmcv.FileClient(**self.file_client_args)
 
-    def transform(self, results: dict) -> dict:
+    def transform(self, results: dict) -> Optional[dict]:
         """Functions to load image.
 
         Args:
@@ -59,9 +63,15 @@ class LoadImageFromFile(BaseTransform):
         """
 
         filename = results['img_path']
+        try:
             img_bytes = self.file_client.get(filename)
             img = mmcv.imfrombytes(
                 img_bytes, flag=self.color_type, backend=self.imdecode_backend)
+        except Exception as e:
+            if self.ignore_empty:
+                return None
+            else:
+                raise e
         if self.to_float32:
             img = img.astype(np.float32)
 
@@ -72,6 +82,7 @@ class LoadImageFromFile(BaseTransform):
 
     def __repr__(self):
         repr_str = (f'{self.__class__.__name__}('
+                    f'ignore_empty={self.ignore_empty}, '
                     f'to_float32={self.to_float32}, '
                     f"color_type='{self.color_type}', "
                     f"imdecode_backend='{self.imdecode_backend}', "

tests/test_transforms/test_transforms_loading.py

@@ -3,6 +3,7 @@ import copy
 import os.path as osp
 
 import numpy as np
+import pytest
 
 from mmcv.transforms import LoadAnnotations, LoadImageFromFile
 
@@ -21,7 +22,7 @@ class TestLoadImageFromFile:
         assert results['img_shape'] == (300, 400)
         assert results['ori_shape'] == (300, 400)
         assert repr(transform) == transform.__class__.__name__ + \
-            "(to_float32=False, color_type='color', " + \
+            "(ignore_empty=False, to_float32=False, color_type='color', " + \
             "imdecode_backend='cv2', file_client_args={'backend': 'disk'})"
 
         # to_float32
@@ -41,6 +42,15 @@ class TestLoadImageFromFile:
         assert results['img'].shape == (300, 400)
         assert results['img'].dtype == np.uint8
 
+        # test load empty
+        fake_img_path = osp.join(data_prefix, 'fake.jpg')
+        results['img_path'] = fake_img_path
+        transform = LoadImageFromFile(ignore_empty=False)
+        with pytest.raises(FileNotFoundError):
+            transform(copy.deepcopy(results))
+        transform = LoadImageFromFile(ignore_empty=True)
+        assert transform(copy.deepcopy(results)) is None
+
 
 class TestLoadAnnotations: