Function _box_inter_union

monai/data/box_utils.py:782–817

This internal function computes the intersection and union area of two set of boxes. Args: boxes1: bounding boxes, Nx4 or Nx6 torch tensor. The box mode is assumed to be ``StandardMode`` boxes2: bounding boxes, Mx4 or Mx6 torch tensor. The box mode is assumed to be ``Standa

(
    boxes1_t: torch.Tensor, boxes2_t: torch.Tensor, compute_dtype: torch.dtype = torch.float32
)

def _box_inter_union(
    boxes1_t: torch.Tensor, boxes2_t: torch.Tensor, compute_dtype: torch.dtype = torch.float32
) -> tuple[torch.Tensor, torch.Tensor]:
    """
    This internal function computes the intersection and union area of two set of boxes.

    Args:
        boxes1: bounding boxes, Nx4 or Nx6 torch tensor. The box mode is assumed to be ``StandardMode``
        boxes2: bounding boxes, Mx4 or Mx6 torch tensor. The box mode is assumed to be ``StandardMode``
        compute_dtype: default torch.float32, dtype with which the results will be computed

    Returns:
        inter, with size of (N,M) and dtype of ``compute_dtype``.
        union, with size of (N,M) and dtype of ``compute_dtype``.

    """
    spatial_dims = get_spatial_dims(boxes=boxes1_t)

    # compute area with float32
    area1 = box_area(boxes=boxes1_t.to(dtype=compute_dtype))  # (N,)
    area2 = box_area(boxes=boxes2_t.to(dtype=compute_dtype))  # (M,)

    # get the left top and right bottom points for the NxM combinations
    lt = torch.max(boxes1_t[:, None, :spatial_dims], boxes2_t[:, :spatial_dims]).to(
        dtype=compute_dtype
    )  # (N,M,spatial_dims) left top
    rb = torch.min(boxes1_t[:, None, spatial_dims:], boxes2_t[:, spatial_dims:]).to(
        dtype=compute_dtype
    )  # (N,M,spatial_dims) right bottom

    # compute size for the intersection region for the NxM combinations
    wh = (rb - lt + TO_REMOVE).clamp(min=0)  # (N,M,spatial_dims)
    inter: torch.Tensor = torch.prod(wh, dim=-1, keepdim=False)  # (N,M)

    union: torch.Tensor = area1[:, None] + area2 - inter  # type: ignore
    return inter, union


def box_iou(boxes1: NdarrayOrTensor, boxes2: NdarrayOrTensor) -> NdarrayOrTensor: