refactor: port RandomVerticalFlip to prototype API (#5524) (#5633)

Co-authored-by: Federico Pozzi <federico.pozzi@argo.vision>

test/test_prototype_transforms.py

@@ -243,3 +243,56 @@ class TestRandomHorizontalFlip:
         assert_equal(expected, actual)
         assert actual.format == expected.format
         assert actual.image_size == expected.image_size
+
+
+@pytest.mark.parametrize("p", [0.0, 1.0])
+class TestRandomVerticalFlip:
+    def input_expected_image_tensor(self, p, dtype=torch.float32):
+        input = torch.tensor([[[1, 1], [0, 0]], [[1, 1], [0, 0]]], dtype=dtype)
+        expected = torch.tensor([[[0, 0], [1, 1]], [[0, 0], [1, 1]]], dtype=dtype)
+
+        return input, expected if p == 1 else input
+
+    def test_simple_tensor(self, p):
+        input, expected = self.input_expected_image_tensor(p)
+        transform = transforms.RandomVerticalFlip(p=p)
+
+        actual = transform(input)
+
+        assert_equal(expected, actual)
+
+    def test_pil_image(self, p):
+        input, expected = self.input_expected_image_tensor(p, dtype=torch.uint8)
+        transform = transforms.RandomVerticalFlip(p=p)
+
+        actual = transform(to_pil_image(input))
+
+        assert_equal(expected, pil_to_tensor(actual))
+
+    def test_features_image(self, p):
+        input, expected = self.input_expected_image_tensor(p)
+        transform = transforms.RandomVerticalFlip(p=p)
+
+        actual = transform(features.Image(input))
+
+        assert_equal(features.Image(expected), actual)
+
+    def test_features_segmentation_mask(self, p):
+        input, expected = self.input_expected_image_tensor(p)
+        transform = transforms.RandomVerticalFlip(p=p)
+
+        actual = transform(features.SegmentationMask(input))
+
+        assert_equal(features.SegmentationMask(expected), actual)
+
+    def test_features_bounding_box(self, p):
+        input = features.BoundingBox([0, 0, 5, 5], format=features.BoundingBoxFormat.XYXY, image_size=(10, 10))
+        transform = transforms.RandomVerticalFlip(p=p)
+
+        actual = transform(input)
+
+        expected_image_tensor = torch.tensor([0, 5, 5, 10]) if p == 1.0 else input
+        expected = features.BoundingBox.new_like(input, data=expected_image_tensor)
+        assert_equal(expected, actual)
+        assert actual.format == expected.format
+        assert actual.image_size == expected.image_size

torchvision/prototype/transforms/__init__.py

@@ -15,6 +15,7 @@ from ._geometry import (
     TenCrop,
     BatchMultiCrop,
     RandomHorizontalFlip,
+    RandomVerticalFlip,
     Pad,
     RandomZoomOut,
 )

torchvision/prototype/transforms/_geometry.py

@@ -45,6 +45,36 @@ class RandomHorizontalFlip(Transform):
             return input
 
 
+class RandomVerticalFlip(Transform):
+    def __init__(self, p: float = 0.5) -> None:
+        super().__init__()
+        self.p = p
+
+    def forward(self, *inputs: Any) -> Any:
+        sample = inputs if len(inputs) > 1 else inputs[0]
+        if torch.rand(1) > self.p:
+            return sample
+
+        return super().forward(sample)
+
+    def _transform(self, input: Any, params: Dict[str, Any]) -> Any:
+        if isinstance(input, features.Image):
+            output = F.vertical_flip_image_tensor(input)
+            return features.Image.new_like(input, output)
+        elif isinstance(input, features.SegmentationMask):
+            output = F.vertical_flip_segmentation_mask(input)
+            return features.SegmentationMask.new_like(input, output)
+        elif isinstance(input, features.BoundingBox):
+            output = F.vertical_flip_bounding_box(input, format=input.format, image_size=input.image_size)
+            return features.BoundingBox.new_like(input, output)
+        elif isinstance(input, PIL.Image.Image):
+            return F.vertical_flip_image_pil(input)
+        elif is_simple_tensor(input):
+            return F.vertical_flip_image_tensor(input)
+        else:
+            return input
+
+
 class Resize(Transform):
     def __init__(
         self,

torchvision/prototype/transforms/functional/__init__.py

@@ -63,6 +63,8 @@ from ._geometry import (
     perspective_image_pil,
     vertical_flip_image_tensor,
     vertical_flip_image_pil,
+    vertical_flip_bounding_box,
+    vertical_flip_segmentation_mask,
     five_crop_image_tensor,
     five_crop_image_pil,
     ten_crop_image_tensor,

torchvision/prototype/transforms/functional/_geometry.py

@@ -81,6 +81,26 @@ vertical_flip_image_tensor = _FT.vflip
 vertical_flip_image_pil = _FP.vflip
 
 
+def vertical_flip_segmentation_mask(segmentation_mask: torch.Tensor) -> torch.Tensor:
+    return vertical_flip_image_tensor(segmentation_mask)
+
+
+def vertical_flip_bounding_box(
+    bounding_box: torch.Tensor, format: features.BoundingBoxFormat, image_size: Tuple[int, int]
+) -> torch.Tensor:
+    shape = bounding_box.shape
+
+    bounding_box = convert_bounding_box_format(
+        bounding_box, old_format=format, new_format=features.BoundingBoxFormat.XYXY
+    ).view(-1, 4)
+
+    bounding_box[:, [1, 3]] = image_size[0] - bounding_box[:, [3, 1]]
+
+    return convert_bounding_box_format(
+        bounding_box, old_format=features.BoundingBoxFormat.XYXY, new_format=format, copy=False
+    ).view(shape)
+
+
 def _affine_parse_args(
     angle: float,
     translate: List[float],