What is difference between intersection over union (IoU) and intersection over bounding box (IoBB)?

Question

Can someone give a detailed explanation IoU and IoBB along with that the differences between them.

Answer 1

The Intersection over Bounding Box is the Intersection over Union (IoU) for object detection tasks, where you have a bounding box.

There are many tasks (e.g. image segmentation) where you have an IoU (the predicted segment vs the actual segment), but there are no bounding boxes.

Answer 2

If you are talking about IoBB (Intersection over detected B-Box) used in medical imaging, I think it is different from IoU. IoBB would divide overlapped area over the area of detected B-Box not the Union of it.

In medical imaging, sometimes the detector identified smaller parts of a large or scattered lesion with a big ground-truth bounding-box so IoBB is used.

Actually I am also looking for a strict definition of IoBB since when I calculated the IoU from my result, it was quite different from the reference result where used IoBB instead of IoU..