Minor fix to casting masks in AMG post-processing (#780)

* Minor fix to casting masks in nms

* Cast to torch.bool

micro_sam/_vendored.py

@@ -29,7 +29,7 @@ def njit(func):
 
 
 def batched_mask_to_box(masks: torch.Tensor) -> torch.Tensor:
-    """Calculates boxes in XYXY format around masks. Return [0,0,0,0] for an empty mask.
+    """Calculates boxes in XYXY format around masks. Return [0, 0, 0, 0] for an empty mask.
 
     For input shape C1xC2x...xHxW, the output shape is C1xC2x...x4.
 
@@ -38,7 +38,7 @@ def batched_mask_to_box(masks: torch.Tensor) -> torch.Tensor:
     It further ensures that inputs are boolean tensors, otherwise the function yields wrong results.
     See https://github.com/facebookresearch/segment-anything/issues/552 for details.
     """
-    assert masks.dtype == torch.bool
+    assert masks.dtype == torch.bool, masks.dtype
 
     # torch.max below raises an error on empty inputs, just skip in this case
     if torch.numel(masks) == 0:

micro_sam/instance_segmentation.py

@@ -215,7 +215,7 @@ def _postprocess_small_regions(self, mask_data, min_area, nms_thresh):
 
         # recalculate boxes and remove any new duplicates
         masks = torch.cat(new_masks, dim=0)
-        boxes = batched_mask_to_box(masks)
+        boxes = batched_mask_to_box(masks.to(torch.bool))  # Casting this to boolean as we work with one-hot labels.
         keep_by_nms = batched_nms(
             boxes.float(),
             torch.as_tensor(scores, dtype=torch.float),