sections/intro/faster_rcnn_approach.md

For example, a FasterRCNN approach uses the following steps:

• the image features are given out by a FPN (Feature Pyramid Net) over a ResNet backbone, and
• then a RPN (Regision Proposal Network) layer detects proposals in those features, and
• then the ROI (Region of Interest) heads get the box proposals in the original image, and
• then the boxes are selected using a NMS (Non-max suppression),
• and then the features for selected boxes are used as visual features.