I'm having problems in finding the best network and configuration to detect small-scale objects. Since now I got very Los mAPs on small objects (i am trying to detect traffic Signs using mapillary dataset)

I have tried using Faster R-CNN 101 (resizing the input to 1024) and the SSD 101 with FPN (resizing the input to 1024).
I did not find a pre-trained model of faster R-CNN with FPN so i could not try that.

What do you think would be the best network and confuguration to detect small objects?

Thank you.