feat: add vision transfer backbones and IMF variants

tests/test_simple_robot_dataset_image_loading.py

@@ -56,3 +56,26 @@ class SimpleRobotDatasetImageLoadingTest(unittest.TestCase):
 
         self.assertEqual(len(resize_calls), 2)
         self.assertEqual(tuple(sample["observation.front"].shape), (2, 3, 8, 8))
+
+    def test_getitem_skips_resize_when_image_resize_shape_is_none(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            dataset_dir = Path(tmpdir)
+            self._write_episode(dataset_dir)
+            dataset = SimpleRobotDataset(
+                dataset_dir,
+                obs_horizon=2,
+                pred_horizon=3,
+                camera_names=["front"],
+                image_resize_shape=None,
+            )
+
+            fake_cv2 = types.SimpleNamespace(
+                INTER_LINEAR=1,
+                resize=mock.Mock(side_effect=AssertionError("resize should be skipped when image_resize_shape=None")),
+            )
+
+            with mock.patch.dict(sys.modules, {"cv2": fake_cv2}):
+                sample = dataset[1]
+
+        fake_cv2.resize.assert_not_called()
+        self.assertEqual(tuple(sample["observation.front"].shape), (2, 3, 8, 8))