I am trying to implement the Faster RCNN on identifying the airplane from the image. I stuck at implementing Region Proposal Network(RPN). How can I implement RPN and train them to produce bounding box proposal using python script?
There are plenty of ready-to-use implementations of various neural networks including Faster RCNN. Consider using DL frameworks such as Pytorch or Keras. For example, see this Pytorch tutorial on fine-tuning the Mask R-CNN model.
Faster RCNN is a two-stage object detection model. Where the first stage is an RPN (Region Proposal Network), and the second is a classifier. For your task, you can ignore the second part if you don't need it.
Some implementations: