Adds torchscript Compatibility to box_convert (#2737)

* fixies small bug in box_convert

* activates jit test

* Passes JIT test

* fixes typo

* adds error tests, removes assert

* implements to proposal2

test/test_ops.py

@@ -727,20 +727,30 @@ class BoxTester(unittest.TestCase):
         self.assertEqual(box_xywh.dtype, box_tensor.dtype)
         assert torch.all(torch.eq(box_xywh, box_tensor)).item()
 
-    # def test_bbox_convert_jit(self):
-    #     box_tensor = torch.tensor([[0, 0, 100, 100], [0, 0, 0, 0],
-    #                               [10, 15, 30, 35], [23, 35, 93, 95]], dtype=torch.float)
+    def test_bbox_invalid(self):
+        box_tensor = torch.tensor([[0, 0, 100, 100], [0, 0, 0, 0],
+                                  [10, 15, 20, 20], [23, 35, 70, 60]], dtype=torch.float)
+
+        invalid_infmts = ["xwyh", "cxwyh"]
+        invalid_outfmts = ["xwcx", "xhwcy"]
+        for inv_infmt in invalid_infmts:
+            for inv_outfmt in invalid_outfmts:
+                self.assertRaises(ValueError, ops.box_convert, box_tensor, inv_infmt, inv_outfmt)
+
+    def test_bbox_convert_jit(self):
+        box_tensor = torch.tensor([[0, 0, 100, 100], [0, 0, 0, 0],
+                                  [10, 15, 30, 35], [23, 35, 93, 95]], dtype=torch.float)
 
-    #     scripted_fn = torch.jit.script(ops.box_convert)
-    #     TOLERANCE = 1e-3
+        scripted_fn = torch.jit.script(ops.box_convert)
+        TOLERANCE = 1e-3
 
-    #     box_xywh = ops.box_convert(box_tensor, in_fmt="xyxy", out_fmt="xywh")
-    #     scripted_xywh = scripted_fn(box_tensor, 'xyxy', 'xywh')
-    #     self.assertTrue((scripted_xywh - box_xywh).abs().max() < TOLERANCE)
+        box_xywh = ops.box_convert(box_tensor, in_fmt="xyxy", out_fmt="xywh")
+        scripted_xywh = scripted_fn(box_tensor, 'xyxy', 'xywh')
+        self.assertTrue((scripted_xywh - box_xywh).abs().max() < TOLERANCE)
 
-    #     box_cxcywh = ops.box_convert(box_tensor, in_fmt="xyxy", out_fmt="cxcywh")
-    #     scripted_cxcywh = scripted_fn(box_tensor, 'xyxy', 'cxcywh')
-    #     self.assertTrue((scripted_cxcywh - box_cxcywh).abs().max() < TOLERANCE)
+        box_cxcywh = ops.box_convert(box_tensor, in_fmt="xyxy", out_fmt="cxcywh")
+        scripted_cxcywh = scripted_fn(box_tensor, 'xyxy', 'cxcywh')
+        self.assertTrue((scripted_cxcywh - box_cxcywh).abs().max() < TOLERANCE)
 
 
 class BoxAreaTester(unittest.TestCase):

torchvision/ops/_box_convert.py

@@ -77,7 +77,7 @@ def _box_xyxy_to_xywh(boxes: Tensor) -> Tensor:
         boxes (Tensor[N, 4]): boxes in (x, y, w, h) format.
     """
     x1, y1, x2, y2 = boxes.unbind(-1)
-    x2 = x2 - x1  # x2 - x1
-    y2 = y2 - y1  # y2 - y1
-    boxes = torch.stack((x1, y1, x2, y2), dim=-1)
+    w = x2 - x1  # x2 - x1
+    h = y2 - y1  # y2 - y1
+    boxes = torch.stack((x1, y1, w, h), dim=-1)
     return boxes

torchvision/ops/boxes.py

@@ -154,39 +154,33 @@ def box_convert(boxes: Tensor, in_fmt: str, out_fmt: str) -> Tensor:
     Returns:
         boxes (Tensor[N, 4]): Boxes into converted format.
     """
+
     allowed_fmts = ("xyxy", "xywh", "cxcywh")
-    assert in_fmt in allowed_fmts
-    assert out_fmt in allowed_fmts
+    if in_fmt not in allowed_fmts or out_fmt not in allowed_fmts:
+        raise ValueError("Unsupported Bounding Box Conversions for given in_fmt and out_fmt")
 
     if in_fmt == out_fmt:
-        boxes_converted = boxes.clone()
-        return boxes_converted
+        return boxes.clone()
 
     if in_fmt != 'xyxy' and out_fmt != 'xyxy':
+        # convert to xyxy and change in_fmt xyxy
         if in_fmt == "xywh":
-            boxes_xyxy = _box_xywh_to_xyxy(boxes)
-            if out_fmt == "cxcywh":
-                boxes_converted = _box_xyxy_to_cxcywh(boxes_xyxy)
-
+            boxes = _box_xywh_to_xyxy(boxes)
         elif in_fmt == "cxcywh":
-            boxes_xyxy = _box_cxcywh_to_xyxy(boxes)
-            if out_fmt == "xywh":
-                boxes_converted = _box_xyxy_to_xywh(boxes_xyxy)
+            boxes = _box_cxcywh_to_xyxy(boxes)
+        in_fmt = 'xyxy'
 
-        # convert one to xyxy and change either in_fmt or out_fmt to xyxy
-    else:
     if in_fmt == "xyxy":
         if out_fmt == "xywh":
-                boxes_converted = _box_xyxy_to_xywh(boxes)
+            boxes = _box_xyxy_to_xywh(boxes)
         elif out_fmt == "cxcywh":
-                boxes_converted = _box_xyxy_to_cxcywh(boxes)
+            boxes = _box_xyxy_to_cxcywh(boxes)
     elif out_fmt == "xyxy":
         if in_fmt == "xywh":
-                boxes_converted = _box_xywh_to_xyxy(boxes)
+            boxes = _box_xywh_to_xyxy(boxes)
         elif in_fmt == "cxcywh":
-                boxes_converted = _box_cxcywh_to_xyxy(boxes)
-
-    return boxes_converted
+            boxes = _box_cxcywh_to_xyxy(boxes)
+    return boxes
 
 
 def box_area(boxes: Tensor) -> Tensor: