python:
def bbox_overlaps_py(boxes, query_boxes):
"""
determine overlaps between boxes and query_boxes
:param boxes: n * 4 bounding boxes
:param query_boxes: k * 4 bounding boxes
:return: overlaps: n * k overlaps
"""
n_ = boxes.shape[0]
k_ = query_boxes.shape[0]
overlaps = np.zeros((n_, k_), dtype=np.float)
for k in range(k_):
query_box_area = (query_boxes[k, 2] - query_boxes[k, 0] +
1) * (query_boxes[k, 3] - query_boxes[k, 1] + 1)
for n in range(n_):
iw = min(boxes[n, 2], query_boxes[k, 2]) - max(
boxes[n, 0], query_boxes[k, 0]) + 1
if iw > 0:
ih = min(boxes[n, 3], query_boxes[k, 3]) - max(
boxes[n, 1], query_boxes[k, 1]) + 1
if ih > 0:
box_area = (boxes[n, 2] - box