Include full image with anno in case there's no tile in tile dataset (#3964)

* include full image with anno incase there's no tile in dataset

* update test

Author: eugene123tw

src/otx/core/data/dataset/tile.py

@@ -148,24 +148,24 @@ def _extract_rois(self, image: Image) -> list[BboxIntCoords]:
         tile_h, tile_w = self._tile_size
         h_ovl, w_ovl = self._overlap
 
-        rois: list[BboxIntCoords] = []
+        rois: set[BboxIntCoords] = set()
         cols = range(0, img_w, int(tile_w * (1 - w_ovl)))
         rows = range(0, img_h, int(tile_h * (1 - h_ovl)))
 
         if self.with_full_img:
-            rois += [x1y1x2y2_to_xywh(0, 0, img_w, img_h)]
+            rois.add(x1y1x2y2_to_xywh(0, 0, img_w, img_h))
         for offset_x, offset_y in product(cols, rows):
             x2 = min(offset_x + tile_w, img_w)
             y2 = min(offset_y + tile_h, img_h)
             c_x, c_y, w, h = x1y1x2y2_to_cxcywh(offset_x, offset_y, x2, y2)
             x1, y1, x2, y2 = cxcywh_to_x1y1x2y2(c_x, c_y, w, h)
             x1, y1, x2, y2 = clip_x1y1x2y2(x1, y1, x2, y2, img_w, img_h)
             x1, y1, x2, y2 = (int(v) for v in [x1, y1, x2, y2])
-            rois += [x1y1x2y2_to_xywh(x1, y1, x2, y2)]
+            rois.add(x1y1x2y2_to_xywh(x1, y1, x2, y2))
 
         log.info(f"image: {img_h}x{img_w} ~ tile_size: {self._tile_size}")
         log.info(f"{len(rows)}x{len(cols)} tiles -> {len(rois)} tiles")
-        return rois
+        return list(rois)
 
 
 class OTXTileDatasetFactory:
@@ -242,6 +242,23 @@ def _convert_entity(self, image: np.ndarray, dataset_item: DatasetItem, parent_i
         msg = "Method _convert_entity is not implemented."
         raise NotImplementedError(msg)
 
+    def transform_item(
+        self,
+        item: DatasetItem,
+        tile_size: tuple[int, int],
+        overlap: tuple[float, float],
+        with_full_img: bool,
+    ) -> DmDataset:
+        """Transform a dataset item to tile dataset which contains multiple tiles."""
+        tile_ds = DmDataset.from_iterable([item])
+        return tile_ds.transform(
+            OTXTileTransform,
+            tile_size=tile_size,
+            overlap=overlap,
+            threshold_drop_ann=0.5,
+            with_full_img=with_full_img,
+        )
+
     def get_tiles(
         self,
         image: np.ndarray,
@@ -259,18 +276,24 @@ def get_tiles(
             - tile_entities (list[OTXDataEntity]): List of tile entities.
             - tile_attrs (list[dict]): List of tile attributes.
         """
-        tile_ds = DmDataset.from_iterable([item])
-        tile_ds = tile_ds.transform(
-            OTXTileTransform,
+        tile_ds = self.transform_item(
+            item,
             tile_size=self.tile_config.tile_size,
             overlap=(self.tile_config.overlap, self.tile_config.overlap),
-            threshold_drop_ann=0.5,
             with_full_img=self.tile_config.with_full_img,
         )
 
         if item.subset in VAL_SUBSET_NAMES:
             # NOTE: filter validation tiles with annotations only to avoid evaluation on empty tiles.
             tile_ds = tile_ds.filter("/item/annotation", filter_annotations=True, remove_empty=True)
+            # if tile dataset is empty it means objects are too big to fit in any tile, in this case include full image
+            if len(tile_ds) == 0:
+                tile_ds = self.transform_item(
+                    item,
+                    tile_size=self.tile_config.tile_size,
+                    overlap=(self.tile_config.overlap, self.tile_config.overlap),
+                    with_full_img=True,
+                )
 
         tile_entities: list[OTXDataEntity] = []
         tile_attrs: list[dict] = []

tests/unit/core/utils/test_tile.py

@@ -15,7 +15,7 @@
 
 
 def test_tile_transform_consistency(mocker):
-    # Test that the tiler and tile transform are consistent
+    # Test that OV tiler and PyTorch tile transform are consistent
     rng = np.random.default_rng()
     rnd_tile_size = rng.integers(low=100, high=500)
     rnd_tile_overlap = rng.random()
@@ -39,5 +39,8 @@ def test_tile_transform_consistency(mocker):
     tile_transform.with_full_img = True
 
     dm_rois = [xywh_to_x1y1x2y2(*roi) for roi in tile_transform._extract_rois(dm_image)]
-    # 0 index in tiler is the full image so we skip it
-    assert np.allclose(dm_rois, tiler._tile(np_image))
+    ov_tiler_rois = tiler._tile(np_image)
+
+    assert len(dm_rois) == len(ov_tiler_rois)
+    for dm_roi in dm_rois:
+        assert list(dm_roi) in ov_tiler_rois