Function pairwise_intersection

detectron2/structures/boxes.py:322–341

Given two lists of boxes of size N and M, compute the intersection area between __all__ N x M pairs of boxes. The box order must be (xmin, ymin, xmax, ymax) Args: boxes1,boxes2 (Boxes): two `Boxes`. Contains N & M boxes, respectively. Returns: Tensor: intersect

(boxes1: Boxes, boxes2: Boxes)

def pairwise_intersection(boxes1: Boxes, boxes2: Boxes) -> torch.Tensor:
    """
    Given two lists of boxes of size N and M,
    compute the intersection area between __all__ N x M pairs of boxes.
    The box order must be (xmin, ymin, xmax, ymax)

    Args:
        boxes1,boxes2 (Boxes): two `Boxes`. Contains N & M boxes, respectively.

    Returns:
        Tensor: intersection, sized [N,M].
    """
    boxes1, boxes2 = boxes1.tensor, boxes2.tensor
    width_height = torch.min(boxes1[:, None, 2:], boxes2[:, 2:]) - torch.max(
        boxes1[:, None, :2], boxes2[:, :2]
    )  # [N,M,2]

    width_height.clamp_(min=0)  # [N,M,2]
    intersection = width_height.prod(dim=2)  # [N,M]
    return intersection


# implementation from https://github.com/kuangliu/torchcv/blob/master/torchcv/utils/box.py