cython_bbox is widely used in object detection tasks. To my best knowledge, it was first implemented in Faster-RCNN. Since then, almost all object detection projects use the source code directly.
In order to use it in standalone code snippets or small projects, I make it a pypi module. The cython_bbox.pyx is totally borrowed from Faster-RCNN. Thanks RBG!
pip install cython_bbox
from cython_bbox import bbox_overlaps
overlaps = bbox_overlaps(
np.ascontiguousarray(dt, dtype=np.float32),
np.ascontiguousarray(gt, dtype=np.float32)
)