GCNet with pretrianed model on COCO detection?

[hezhu1996]

Hello, I'm not sure if GCNet in mmdetection use ImageNet pretrained model (specifically GCNet + ResNet pretrained model) cause I saw in the GCNet/config, it only uses standard "torchvision://resnet50" in official mmedetection and "modelzoo://resnet50" in this repo as pretrained model, but in the original paper, the auther firstly trained on ImageNet and transfor to COCO detection task.

Would you explain does mmdetection use (ResNet pretrained model) or (ResNet+GC pretrained model)? if you only use ResNet pretrained model, why does COCO have such a large improvement?