DRC²-Net: A Context-Aware and Geometry-Adaptive Network for Lightweight SAR Ship Detection

Synthetic Aperture Radar (SAR) ship detection remains challenging due to background clutter, target sparsity, and fragmented or partially occluded ships, particularly at small scales. To address these issues, we propose the Deformable Recurrent Criss-Cross Attention Network (DRC2-Net), a lightweight and efficient detection framework built upon the YOLOX-Tiny architecture. The model incorporates two SAR-specific modules: a Recurrent Criss-Cross Attention (RCCA) module to enhance contextual awareness and reduce false positives, and a Deformable Convolutional Net-works v2 (DCNv2) module to capture geometric deformations and scale variations adaptively. These modules expand the Effective Receptive Field (ERF) and improve feature adaptability under complex conditions. DRC²-Net is trained on the SSDD and iVision-MRSSD datasets, encompassing highly diverse SAR imagery including inshore and offshore scenes, variable sea states, and complex coastal backgrounds. The model maintains a compact architecture with 5.05M parameters, ensuring strong generalization and real-time applicability. On the SSDD dataset, it outperforms the YOLOX-Tiny baseline with AP@50 of 93.04% (+0.9%), APs of 91.15% (+1.31%), APm of 88.30% (+1.22%), and APl of 89.47% (+13.32%). On the more challenging iVision-MRSSD dataset, it further demonstrates superior scale-aware detection, achieving higher AP across small, medium, and large targets. These results confirm the effectiveness and robustness of DRC2-Net for multi-scale ship detection in complex SAR environments, consistently surpassing state-of-the-art detectors.