HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images

Small object detection (SOD) in remote sensing images (RSIs) is a challenging task due to scale variation, severe occlusion, and complex backgrounds, often leading to high miss and false detection rates. To address these issues, this paper proposes a novel detection framework named HSF-YOLO, which i...

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Main Authors: Fujun Wang, Xing Wang
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/14/4369
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author Fujun Wang
Xing Wang
author_facet Fujun Wang
Xing Wang
author_sort Fujun Wang
collection DOAJ
description Small object detection (SOD) in remote sensing images (RSIs) is a challenging task due to scale variation, severe occlusion, and complex backgrounds, often leading to high miss and false detection rates. To address these issues, this paper proposes a novel detection framework named HSF-YOLO, which is designed to jointly enhance feature encoding, attention interaction, and localization precision within the YOLOv8 backbone. Specifically, we introduce three tailored modules: Hybrid Atrous Enhanced Convolution (HAEC), a Spatial–Interactive–Shuffle attention module (C2f_SIS), and a Focal Gradient Refinement Loss (FGR-Loss). The HAEC module captures multi-scale semantic and fine-grained local information through parallel atrous and standard convolutions, thereby enhancing small object representation across scales. The C2f_SIS module fuses spatial and improved channel attention with a channel shuffle strategy to enhance feature interaction and suppress background noise. The FGR-Loss incorporates gradient-aware localization, focal weighting, and separation-aware constraints to improve regression accuracy and training robustness. Extensive experiments were conducted on three public remote sensing datasets. Compared with the baseline YOLOv8, HSF-YOLO improved mAP@0.5 and mAP@0.5:0.95 by 5.7% and 4.0% on the VisDrone2019 dataset, by 2.3% and 2.5% on the DIOR dataset, and by 2.3% and 2.1% on the NWPU VHR-10 dataset, respectively. These results confirm that HSF-YOLO is a unified and effective solution for small object detection in complex RSI scenarios, offering a good balance between accuracy and efficiency.
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spelling doaj-art-4fe5a05f4d0a458ab2efecf7ddae1acb2025-08-20T03:56:49ZengMDPI AGSensors1424-82202025-07-012514436910.3390/s25144369HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing ImagesFujun Wang0Xing Wang1School of Geomatics, Liaoning Technical University, Fuxin 123000, ChinaSchool of Information Science and Engineering, Linyi University, Linyi 276000, ChinaSmall object detection (SOD) in remote sensing images (RSIs) is a challenging task due to scale variation, severe occlusion, and complex backgrounds, often leading to high miss and false detection rates. To address these issues, this paper proposes a novel detection framework named HSF-YOLO, which is designed to jointly enhance feature encoding, attention interaction, and localization precision within the YOLOv8 backbone. Specifically, we introduce three tailored modules: Hybrid Atrous Enhanced Convolution (HAEC), a Spatial–Interactive–Shuffle attention module (C2f_SIS), and a Focal Gradient Refinement Loss (FGR-Loss). The HAEC module captures multi-scale semantic and fine-grained local information through parallel atrous and standard convolutions, thereby enhancing small object representation across scales. The C2f_SIS module fuses spatial and improved channel attention with a channel shuffle strategy to enhance feature interaction and suppress background noise. The FGR-Loss incorporates gradient-aware localization, focal weighting, and separation-aware constraints to improve regression accuracy and training robustness. Extensive experiments were conducted on three public remote sensing datasets. Compared with the baseline YOLOv8, HSF-YOLO improved mAP@0.5 and mAP@0.5:0.95 by 5.7% and 4.0% on the VisDrone2019 dataset, by 2.3% and 2.5% on the DIOR dataset, and by 2.3% and 2.1% on the NWPU VHR-10 dataset, respectively. These results confirm that HSF-YOLO is a unified and effective solution for small object detection in complex RSI scenarios, offering a good balance between accuracy and efficiency.https://www.mdpi.com/1424-8220/25/14/4369remote sensing imagessmall object detectionmulti-scale feature representationattention mechanism
spellingShingle Fujun Wang
Xing Wang
HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
Sensors
remote sensing images
small object detection
multi-scale feature representation
attention mechanism
title HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
title_full HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
title_fullStr HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
title_full_unstemmed HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
title_short HSF-YOLO: A Multi-Scale and Gradient-Aware Network for Small Object Detection in Remote Sensing Images
title_sort hsf yolo a multi scale and gradient aware network for small object detection in remote sensing images
topic remote sensing images
small object detection
multi-scale feature representation
attention mechanism
url https://www.mdpi.com/1424-8220/25/14/4369
work_keys_str_mv AT fujunwang hsfyoloamultiscaleandgradientawarenetworkforsmallobjectdetectioninremotesensingimages
AT xingwang hsfyoloamultiscaleandgradientawarenetworkforsmallobjectdetectioninremotesensingimages