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xingyizhou / CenterNet2

Two-stage CenterNet
Apache License 2.0
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Is CenterNet2 also an anchor-free algorithm？ #18

Closed mucle closed 3 years ago

mucle commented 3 years ago

Please select an issue template from https://github.com/facebookresearch/detectron2/issues/new/choose .

Otherwise your issue will be closed.

xingyizhou commented 3 years ago

Great question! In a narrow anchor definition, I would say yes, because we don't need to design the ratio/ size of anchors. However, in a broad anchor definition, it needs a fixed rule to assign objects to each FPN level, and does requires hyper-parameters about object sizes. Anyway, we can safely say the non-FPN version (i.e., stride 4) of CenterNet/ CenterNet2 is anchor-free (if that matters).

Best, Xingyi