FPN Paper Walkthrough: Leveraging the Internal Pyramid

Modern object detection models are often structured with a backbone, neck, and head, where the neck enhances features for better prediction. Feature Pyramid Networks (FPN) function as a neck to solve the challenge of detecting small objects. FPN creates a top-down pathway to propagate rich semantic information from deeper layers to shallower ones. This information is merged with high-resolution spatial features from the shallower layers via lateral connections, creating semantically strong feature maps at all scales for improved detection accuracy.