Structural damage detection via hierarchical damage information with volumetric assessment

Vision-based structural inspection is essential for ensuring the safety and longevity of infrastructure, but complex image environments, noisy labels, and reliance on manual damage assessments often hinder its effectiveness. This study introduces the Guided Detection Network (Guided-DetNet), a framework designed to address these challenges. Guided-DetNet is characterized by a Generative Attention Module (GAM), Hierarchical Elimination Algorithm (HEA), and Volumetric Contour Visual Assessment (VCVA). GAM leverages cross-horizontal and cross-vertical patch merging, as well as cross-foreground-background feature fusion, to generate diverse features that mitigate complex image environments. HEA addresses noisy labeling by utilizing hierarchical relationships among classes to refine instances given an image, thereby eliminating unlikely class instances. VCVA assesses the severity of detected damages via volumetric representation and quantification, leveraging the Dirac delta distribution. A comprehensive quantitative study and two robustness tests were conducted using the Pacific Earthquake Engineering Research (PEER) Hub Image-Network dataset. A drone-based application, which involved a field experiment, was also conducted to substantiate Guided-DetNet's promising performance. In triple classification tasks, the framework achieved 96% accuracy, surpassing state-of-the-art classifiers by up to 3%. In dual detection tasks, it outperformed competitive detectors with a precision of 94% and a mean average precision (mAP) of 79%, while maintaining a frame rate of 57.04 frames per second, suitable for real-time applications. Additionally, robustness tests demonstrated resilience under adverse conditions, with precision scores ranging from 79% to 91%. Guided-DetNet is established as a robust and efficient framework for structural inspection, offering advancements in automation and precision, with the potential for widespread application in drone-based infrastructure inspections.