--- title: PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up description: PANet (Path Aggregation Network) extends FPN by adding a bottom-up path augmentation that shortens the information flow between shallow and deep feature maps.... canonical: https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up | daily.dev og:description: PANet (Path Aggregation Network) extends FPN by adding a bottom-up path augmentation that shortens the information flow between shallow and deep feature maps.... og:url: https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7 og:image: https://api.daily.dev/og/posts/WBnvzuic7.png og:image:alt: PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up **[Towards Data Science](https://daily.dev/sources/tds)** · 18 min read · 0 upvotes · 0 comments ## Summary PANet (Path Aggregation Network) extends FPN by adding a bottom-up path augmentation that shortens the information flow between shallow and deep feature maps. While FPN enriches shallow layers with semantic information via a top-down pathway, it leaves deeper layers lacking spatial information. PANet addresses this by adding a few convolution layers that propagate spatial information upward, reducing the path from 100+ backbone layers to roughly 10. The post walks through the architecture in detail and provides a from-scratch PyTorch implementation covering the CNN backbone, FPN, and PANet components assembled into a single BackboneNeck class. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [FPN Paper Walkthrough: Leveraging the Internal Pyramid](https://daily.dev/posts/fpn-paper-walkthrough-leveraging-the-internal-pyramid-pwid4rojp) · Towards Data Science · 0 upvotes · 0 comments - [SPP-Net Paper Walkthrough: Breaking the Fixed-Size Constraint](https://daily.dev/posts/spp-net-paper-walkthrough-breaking-the-fixed-size-constraint-q5nkoikyj) · Towards Data Science · 0 upvotes · 0 comments - [CSPNet Paper Walkthrough: Just Better, No Tradeoffs](https://daily.dev/posts/cspnet-paper-walkthrough-just-better-no-tradeoffs-fqrnxz0s3) · Towards Data Science · 1 upvotes · 0 comments - [MobileNetV2 Paper Walkthrough: The Smarter Tiny Giant](https://daily.dev/posts/mobilenetv2-paper-walkthrough-the-smarter-tiny-giant-1vcktzlmp) · Towards Data Science · 1 upvotes · 0 comments --- Tags: [#deep-learning](https://daily.dev/tags/deep-learning), [#pytorch](https://daily.dev/tags/pytorch), [#object-detection](https://daily.dev/tags/object-detection) [View this post on daily.dev](https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up","url":"https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7"},"datePublished":"2026-07-05T13:58:51.555Z","dateModified":"2026-07-05T13:59:15.733Z","description":"PANet (Path Aggregation Network) extends FPN by adding a bottom-up path augmentation that shortens the information flow between shallow and deep feature maps....","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6883966c99f56bc70470554a518d2936?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6883966c99f56bc70470554a518d2936?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Towards Data Science","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Towards Data Science","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/tds","url":"https://daily.dev/sources/tds"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/panet-paper-walkthrough-when-feature-pyramids-go-bottom-up-wbnvzuic7","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"deep-learning,pytorch,object-detection","timeRequired":"PT18M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Towards Data Science","item":"https://daily.dev/sources/tds"},{"@type":"ListItem","position":3,"name":"PANet Paper Walkthrough: When Feature Pyramids Go Bottom-Up"}]} ```