What is the RPN in mmdetection?

[yuhua666]

I hope to replicate the original version of fast rcnn. I noticed that the replicated version of fast rcnn of mmdetection includes Shared2FCBBoxHead, which is not what I want.
I see an RPN detector in mmdetection. It seems that there is a Shared2FCBBoxHead less than the fast rcnn version in the network structure. Is this the corresponding original fast rcnn?
In short, I hope to find a version of mmdetection similar to the original version of fast rcnn. Can anyone help me?

[Maenansyn]

Fast R-CNN takes an input image and region proposals as input, as described in the original paper. So you need the RPN in front of Fast R-CNN as its output is part of the input of Fast R-CNN.. this is also noted in the respective Git.

The RPNHead is here and a default config as used in the later Faster R-CNN can be found in its config.