BFD-YOLO: A YOLOv7-Based Detection Method for Building Façade Defects

Abstract

Façade defects not only detract from the building’s aesthetics but also compromise its performance. Furthermore, they potentially endanger pedestrians, occupants, and property. Existing deep-learning-based methodologies are facing some challenges in terms of recognition speed and model complexity. An improved YOLOv7 method, named BFD-YOLO, is proposed to ensure the accuracy and speed of building façade defects detection in this paper. Firstly, the original ELAN module in YOLOv7 was substituted with a lightweight MobileOne module to diminish the quantity of parameters and enhance the speed of inference. Secondly, the coordinate attention module was added to the model to enhance feature extraction capability. Next, the SCYLLA-IoU was used to expedite the rate of convergence and increase the recall of the model. Finally, we have extended the open datasets to construct a building façade damage dataset that includes three typical defects. BFD-YOLO demonstrates excellent accuracy and efficiency based on this dataset. Compared to YOLOv7, BFD-YOLO’s precision and mAP@.5 are improved by 2.2% and 2.9%, respectively, while maintaining comparable efficiency. The experimental results indicate that the proposed method obtained higher detection accuracy with guaranteed real-time performance.