This study proposes an integrated system for automated safety management that automatically identifies safety hazards at construction sites using drone imagery. The construction industry remains labor-intensive and is characterized by high-risk enviro...
This study proposes an integrated system for automated safety management that automatically identifies safety hazards at construction sites using drone imagery. The construction industry remains labor-intensive and is characterized by high-risk environments where major accidents such as falls, collapses, and collisions occur frequently. In particular, excavation boundaries and blasting operations at earthwork sites are significant safety hazards, yet their management has largely relied on visual inspection, limiting effective safety control. To address this issue, this study introduces a safety management system that detects excavation boundaries and on-site individuals using drone imagery.
In the boundary detection process, initial outlines were extracted using Canny edge detection, followed by morphological closing to ensure boundary continuity. Principal Component Analysis (PCA) was then applied to quantify the predominant orientation of irregular excavation boundaries. Experiments were conducted at different flight altitudes (50 m, 70m , 100 m), camera angles (60°, 90°), and flight directions (north-south, east-west). Results showed that vertical imagery at 90° produced approximately 2% error compared with GNSS-RTK (Global Navigation Satellite System-Real-Time Kinematic) survey data, while at 50m altitude, the error was only 0.05 m compared to the reference value. These findings demonstrated higher accuracy than conventional edge detection methods and confirmed applicability to practical tasks such as earthwork volume estimation and slope stability assessment.
For human detection, the YOLOv5 model was applied. Initial training used the VisDrone2019-DET public dataset, followed by transfer learning with approximately 1,600 real construction site images collected for this study, thereby enhancing field applicability. As a result, the YOLOv5l model achieved mAP@0.5 = 0.455 and maintained robust detection under diverse conditions and complex backgrounds. Resolution-based analysis revealed that with 1280-pixel input, YOLOv5l yielded a detection rate of 85.7%, YOLOv5m achieved 83.3%, and YOLOv5s achieved 85.7%. At low resolution (640 pixels), detection rates decreased to 55-71%. These results provide practical guidelines for determining the optimal image resolution and model configuration in drone-based safety monitoring.
In summary, this study developed an integrated safety management system that combines boundary detection and human detection, thus distinguishing it from previous research. Furthermore, when linked with BIM (Building Information Modeling) and digital twin technologies, the proposed system can support verification of deviations from design plans, identification of unauthorized access to hazardous zones, and evaluation of safety compliance, thereby demonstrating its potential to evolve into a smart construction safety management platform. Looking ahead, if sensor fusion, lightweight algorithm design, and institutional framework development advance in parallel, the proposed system could become a core safety management technology in the era of smart construction.