Why IOU balanced sampling reduces accuracy instead？

[ModestYjx]

• I add IOU balanced sampling module on BFP_BLL strategy, but m-ap is reduced.
• I want to know why this result happend.
  Here are my experiment results:

experiment_BFP_BLL

([('bbox_mAP', 0.37),
('bbox_mAP_50', 0.578),
('bbox_mAP_75', 0.402),
('bbox_mAP_s', 0.221),
('bbox_mAP_m', 0.405),
('bbox_mAP_l', 0.465),
('bbox_mAP_copypaste', '0.370 0.578 0.402 0.221 0.405 0.465'),
('mAP', 0.425),
('mAP_50', 0.682),
('mAP_75', 0.455),
('mAP_s', 0.281),
('mAP_m', 0.484),
('mAP_l', 0.595)])

experiment_BFP_BLL_IOUBS

([('bbox_mAP', 0.364),
('bbox_mAP_50', 0.567),
('bbox_mAP_75', 0.395),
('bbox_mAP_s', 0.209),
('bbox_mAP_m', 0.399),
('bbox_mAP_l', 0.462),
('bbox_mAP_copypaste', '0.364 0.567 0.395 0.209 0.399 0.462'),
('mAP', 0.422),
('mAP_50', 0.673),
('mAP_75', 0.451),
('mAP_s', 0.271),
('mAP_m', 0.477),
('mAP_l', 0.596)])

• If you need my code, I could send it to you to check this problem .

[mmoghadam11]

• I add IOU balanced sampling module on BFP_BLL strategy, but m-ap is reduced.
• I want to know why this result happend.
  Here are my experiment results:

experiment_BFP_BLL

([('bbox_mAP', 0.37),
('bbox_mAP_50', 0.578),
('bbox_mAP_75', 0.402),
('bbox_mAP_s', 0.221),
('bbox_mAP_m', 0.405),
('bbox_mAP_l', 0.465),
('bbox_mAP_copypaste', '0.370 0.578 0.402 0.221 0.405 0.465'),
('mAP', 0.425),
('mAP_50', 0.682),
('mAP_75', 0.455),
('mAP_s', 0.281),
('mAP_m', 0.484),
('mAP_l', 0.595)])

experiment_BFP_BLL_IOUBS

([('bbox_mAP', 0.364),
('bbox_mAP_50', 0.567),
('bbox_mAP_75', 0.395),
('bbox_mAP_s', 0.209),
('bbox_mAP_m', 0.399),
('bbox_mAP_l', 0.462),
('bbox_mAP_copypaste', '0.364 0.567 0.395 0.209 0.399 0.462'),
('mAP', 0.422),
('mAP_50', 0.673),
('mAP_75', 0.451),
('mAP_s', 0.271),
('mAP_m', 0.477),
('mAP_l', 0.596)])

• If you need my code, I could send it to you to check this problem .

i have this problem too
why it makes lower ap???