I am trying to implement a pretrained model from the Detectron2 library for object detection and it seems that Faster R-CNN models outperform the RetinaNet models. However, when accessing the model zoo, I came across Faster R-CNN models and RPN Faster R-CNN models. I scoured the internet but I am struggling to find the difference between these models. Does not Faster R-CNN already use RPN?
Model Zoo: https://github.com/facebookresearch/detectron2/blob/main/MODEL_ZOO.md