A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9
Research Article  ·  Published: 25 September 2026
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Chinese Journal of Information Fusion
Volume 3, Issue 3, 2026: 166-177
Research Article Open Access

A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9

1 College of Electronic Science, National University of Defense Technology, Changsha 410073, China
2 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
3 Key Laboratory of Automatic Target Recognition, National University of Defense Technology, Changsha 410073, China
* Corresponding Author: Moufa Hu, [email protected]
This article belongs to the Special Topic: Pattern Recognition and Information Fusion
Volume 3, Issue 3
You have full access to this open access article · CC BY 4.0 License

Article Information

Abstract

To address the safety hazards posed by unauthorized "black flight" of unmanned aerial vehicle (UAV) clusters, as well as the limitations of existing detection methods in tiny target recognition and complex environment adaptability, this paper proposes a real-time detection and counting method based on a feature fusion framework. The core contribution of this work is a novel multi-level fusion architecture that aggregates multi-scale visual features to enhance detection robustness under challenging conditions. First, we construct a multi scene UAV data set containing 7,113 images, and design a dedicated feature fusion module based on improved YOLOv9 backbone. The Haar Wavelet Down-sampling (HWD) module is introduced to fuse high-frequency edge details with low-frequency approximation features, preserving critical texture information that is essential for tiny target detection. The Programmable Gradient Information (PGI) mechanism is adopted as an auxiliary reversible branch, which propagates reliable deep-layer gradient information to shallow layers to effectively mitigate the information bottleneck problem. Second, a decision-level fusion strategy is developed to aggregate confidence scores and localization outputs from multi-scale predictions. The strategy is further optimized with a tailored Non-Maximum Suppression (NMS) algorithm to resolve occlusion issues in dense UAV clusters. Evaluations on the self-built dense UAV dataset show that the proposed method achieves a detection accuracy of 85% with a per-frame processing time of 0.10–0.15 s. Tests across diverse scenarios validate that the method can accurately locate and identify UAV targets. By achieving a favorable balance between detection accuracy and real-time performance, the proposed method effectively alleviates the missed detection and false detection problems in dense UAV cluster detection tasks.

Graphical Abstract

A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9

Keywords

UAV cluster target detection YOLOv9 deep learning low altitude safety feature fusion

Data Availability Statement

Data will be made available on request.

Funding

This work was supported without any funding.

Conflicts of Interest

The authors declare no conflicts of interest.

AI Use Statement

The authors declare that DeepSeek-R1 was used for language editing, and DeepL Translator was used for translation of manuscript from Chinese into English. The authors have carefully reviewed, revised, and verified the AI-assisted output and take full responsibility for the content of the manuscript.

Ethical Approval and Consent to Participate

Not applicable.

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Cite This Article

APA Style
Lu, X., Chen, S., Sun, J., Yin, Z., & Hu, M. (2026). A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9. Chinese Journal of Information Fusion, 3(3), 166-177. https://doi.org/10.62762/CJIF.2026.233582
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TY  - JOUR
AU  - Lu, Xinpeng
AU  - Chen, Shijie
AU  - Sun, Jiashuo
AU  - Yin, Zhichao
AU  - Hu, Moufa
PY  - 2026
DA  - 2026/09/25
TI  - A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9
JO  - Chinese Journal of Information Fusion
T2  - Chinese Journal of Information Fusion
JF  - Chinese Journal of Information Fusion
VL  - 3
IS  - 3
SP  - 166
EP  - 177
DO  - 10.62762/CJIF.2026.233582
UR  - https://www.icck.org/article/abs/CJIF.2026.233582
KW  - UAV cluster
KW  - target detection
KW  - YOLOv9
KW  - deep learning
KW  - low altitude safety
KW  - feature fusion
AB  - To address the safety hazards posed by unauthorized "black flight" of unmanned aerial vehicle (UAV) clusters, as well as the limitations of existing detection methods in tiny target recognition and complex environment adaptability, this paper proposes a real-time detection and counting method based on a feature fusion framework. The core contribution of this work is a novel multi-level fusion architecture that aggregates multi-scale visual features to enhance detection robustness under challenging conditions. First, we construct a multi scene UAV data set containing 7,113 images, and design a dedicated feature fusion module based on improved YOLOv9 backbone. The Haar Wavelet Down-sampling (HWD) module is introduced to fuse high-frequency edge details with low-frequency approximation features, preserving critical texture information that is essential for tiny target detection. The Programmable Gradient Information (PGI) mechanism is adopted as an auxiliary reversible branch, which propagates reliable deep-layer gradient information to shallow layers to effectively mitigate the information bottleneck problem. Second, a decision-level fusion strategy is developed to aggregate confidence scores and localization outputs from multi-scale predictions. The strategy is further optimized with a tailored Non-Maximum Suppression (NMS) algorithm to resolve occlusion issues in dense UAV clusters. Evaluations on the self-built dense UAV dataset show that the proposed method achieves a detection accuracy of 85% with a per-frame processing time of 0.10–0.15 s. Tests across diverse scenarios validate that the method can accurately locate and identify UAV targets. By achieving a favorable balance between detection accuracy and real-time performance, the proposed method effectively alleviates the missed detection and false detection problems in dense UAV cluster detection tasks.
SN  - 2998-3371
PB  - Institute of Central Computation and Knowledge
LA  - English
ER  - 
BibTeX Format
Compatible with LaTeX, BibTeX, and other reference managers
@article{Lu2026A,
  author = {Xinpeng Lu and Shijie Chen and Jiashuo Sun and Zhichao Yin and Moufa Hu},
  title = {A Multi-Scale UAV Cluster Detection and Counting Framework Based on Multi-Source Information Fusion and Enhanced YOLOv9},
  journal = {Chinese Journal of Information Fusion},
  year = {2026},
  volume = {3},
  number = {3},
  pages = {166-177},
  doi = {10.62762/CJIF.2026.233582},
  url = {https://www.icck.org/article/abs/CJIF.2026.233582},
  abstract = {To address the safety hazards posed by unauthorized "black flight" of unmanned aerial vehicle (UAV) clusters, as well as the limitations of existing detection methods in tiny target recognition and complex environment adaptability, this paper proposes a real-time detection and counting method based on a feature fusion framework. The core contribution of this work is a novel multi-level fusion architecture that aggregates multi-scale visual features to enhance detection robustness under challenging conditions. First, we construct a multi scene UAV data set containing 7,113 images, and design a dedicated feature fusion module based on improved YOLOv9 backbone. The Haar Wavelet Down-sampling (HWD) module is introduced to fuse high-frequency edge details with low-frequency approximation features, preserving critical texture information that is essential for tiny target detection. The Programmable Gradient Information (PGI) mechanism is adopted as an auxiliary reversible branch, which propagates reliable deep-layer gradient information to shallow layers to effectively mitigate the information bottleneck problem. Second, a decision-level fusion strategy is developed to aggregate confidence scores and localization outputs from multi-scale predictions. The strategy is further optimized with a tailored Non-Maximum Suppression (NMS) algorithm to resolve occlusion issues in dense UAV clusters. Evaluations on the self-built dense UAV dataset show that the proposed method achieves a detection accuracy of 85\% with a per-frame processing time of 0.10–0.15 s. Tests across diverse scenarios validate that the method can accurately locate and identify UAV targets. By achieving a favorable balance between detection accuracy and real-time performance, the proposed method effectively alleviates the missed detection and false detection problems in dense UAV cluster detection tasks.},
  keywords = {UAV cluster, target detection, YOLOv9, deep learning, low altitude safety, feature fusion},
  issn = {2998-3371},
  publisher = {Institute of Central Computation and Knowledge}
}

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CC BY Copyright © 2026 by the Author(s). Published by Institute of Central Computation and Knowledge. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
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