DyFrDet: Towards Accurate Small Object Detection via Dynamic Frequency Suppression with Label Disambiguation
Zihan Yang1*
Yang Guo2*
Hongxing Zhang3
Dan Lu1✉
Siyuan Yao4✉
1 Hangzhou International Innovation Institute, Beihang University
2 Beijing University of Posts and Telecommunications (BUPT)
3 School of Beijing University of Posts and Telecommunications
4 Shenzhen Campus of Sun Yat-sen University
* Equal contribution ✉ Corresponding authors
[](https://arxiv.org/abs/2608.02495)
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> **🎉 Accepted by ACMMM 2026**
> Official PyTorch implementation of **DyFrDet**.
📌 **Note:** This repository provides the official implementation of DyFrDet, designed to resolve background distractions in the frequency domain and mitigate label ambiguity in small object detection.
## 📖 Abstract
Despite the remarkable progress over the past decades, accurately identifying small objects remains challenging because of their insufficient visual cues. Previous works typically attempt to construct discriminative representation of the small objects. However, the wide range frequency domain noises and label ambiguities have been greatly overlooked, which significantly hinders the accurate localization. To address these issues, we propose a novel small object detection (SOD) detector termed DyFrDet, which is able to precisely localize the small object by dynamically suppressing the background distractions in frequency domain. Specifically, we propose a Dynamic Frequency-aware Feature Pyramid Network (DyFrFPN) to adaptively suppress low-frequency redundancy and excessive high-frequency noises. The DyFrFPN transforms the hierarchical features into frequency domain representation, and introduces a Dynamic Band Predictor (DBP) to preserve the discriminative components for small object identification. Afterwards, we present a novel Label Disambiguation Module (LDM), which leverages probabilistic distributions to explicitly model and alleviate the inherent ambiguity of target labels, yielding efficient improvement in localization precision of the small objects with low-resolution. Extensive experiments demonstrate that DyFrDet achieves state-of-the-art performance across multiple benchmarks, indicating its effectiveness and robustness in various challenging scenarios.
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## 🎬 Overview
