* We provide models based on two detection frameworks, [RetinaNet](https://arxiv.org/abs/1708.02002) or [Mask R-CNN](https://arxiv.org/abs/1703.06870), and two backbones, [ResNet-FPN](https://arxiv.org/abs/1612.03144) or [SpineNet](https://arxiv.org/abs/1912.05027).
* Models are all trained on COCO train2017 and evaluated on COCO val2017.
* Training details:
* Models finetuned from ImageNet pretrained checkpoints adopt the 12 or 36 epochs schedule. Models trained from scratch adopt the 350 epochs schedule.
* The default training data augmentation implements horizontal flipping and scale jittering with a random scale between [0.5, 2.0].
* Unless noted, all models are trained with l2 weight regularization and ReLU activation.
* We use batch size 256 and stepwise learning rate that decays at the last 30 and 10 epoch.
* We use square image as input by resizing the long side of an image to the target size then padding the short side with zeros.