“…These well‐known detectors perform effectively on natural images (e.g., MS COCO (Lin et al, 2014) and Pascal VOC (Everingham et al, 2010)). However, in satellite‐based (or UAV‐based) surveillance (Kaliappan et al, 2022), search and rescue (Balasundaram & Krishnamoorthy, 2022), and military reconnaissance tasks where the targets are migrated to small instances, the performance of small object detection is still far from satisfactory for mainly three challenges, as shown in Figure 1: (1) small size with limited details, rendering the task of distinguishing targets from the background fairly difficult; (2) occlusion with ambiguous boundaries, leading to poor localisation; (3) variant scales with feature inconsistency, resulting in biased detection results for targets with different scales in the same scene. Therefore, small object detection, especially in densely distributed situations of remote sensing scenes, remains an open and challenging problem, requiring urgent efforts.…”