Jul 2026· The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences· Vol XLIX-B2-2026, pp. 1259-1266· 0 citations· 10 references
Abstract
Abstract. Reliable inspection of bridge infrastructure is essential for maintaining structural safety, particularly in identifying missing bolts that may compromise system performance. This study represents an extension of our previous work with a methodology that integrates point cloud-based Digital Twin (DT) models with Topological Data Analysis (TDA), to enable accurate detection and localization of missing bolts. A high-resolution 3D representation of bridge joints is first generated using a photogrammetric reconstruction process. YOLOv8 is then employed to detect and localize bolt positions within the point cloud data. Subsequently, Alpha complexes are utilized within the TDA framework to capture topological features and identify anomalies associated with missing bolts. The approach is validated through a benchmark case study, demonstrating high accuracy in detecting missing bolts and robustness to variations in point cloud density. The results indicate that the integration of DT and TDA provides an effective and reliable solution for advanced structural health monitoring applications.
Geometric digital twinning is an essential step for the holistic storage, analysis, visualization, and interpretation of information about bridges from multiple modalities. Generally, accurate digital twinning depends on high-quality sensing data and the information extracted from such data, whereas the acquisition of high-quality data is typically guided by the information embedded in the model. This data–model coupling suggests that data-based modeling tasks (DBMT) and model-based data tasks (MBDT) should be performed iteratively using the available information at each stage. This research investigates an efficient bridge geometric digital twinning using a parametric bridge generator (PBG) that can accommodate DBMT and MBDT at different levels encountered during field visual inspection. Flexibility and efficiency can be achieved by (1) the PBG generating a model in the photorealistic synthetic environment once key parameters are obtained in the field, (2) flexibly selecting the key parameters depending on the level of accuracy and detail, and (3) enabling the PBG to generate as reasonable a model as possible, even with missing parameters to guide the inspection process. Based on the PBG, this research develops two feasible DBMT and MBDT that can guide bridge inspection and the geometric digital twinning process, model-based data evaluation (MBDE), and data-based model evaluation (DBME). These evaluations are employed to clarify the degree to which modeling requirements are satisfied for a given level of detail. The proposed PBG-based geometric digital twinning approach is demonstrated through two case studies in the field, one for short-span road bridge and one for long-span cable-stayed bridge.
Huayong Wu, Rongxin Zhao, Weilei Yu et al.· ASCE-ASME Journal of Risk an...· 1 citation
The results demonstrate the potential of hybrid AI and geometric approaches to improve the efficiency, repeatability, and reliability of Scan-to-BIM processes for historical masonry bridge heritage and show that the geometric quality of the HBIM model depends primarily on the density, spatial distribution and completeness of the structural points, rather than on their total number.
V. Alfio, Massimiliano Pepe, Donato Palumbo et al.· Applied Sciences· 0 citations
Abstract. Structural inspection is crucial for comprehensive risk management, especially given the accelerated deterioration caused by factors such as climate change and obsolescence. The accurate determination of the percentage of surface damage is fundamental for optimizing maintenance decision-making and the administration of resources for infrastructure preservation. This work presents a methodological exploration to assess the superficial condition of a concrete pedestrian bridge located over an urban river. The study focuses on determining the structural conditions by calculating the percentage of surface damage to evaluate maintenance needs. For data acquisition, Light Detection and Ranging (LiDAR) technology is employed using a Terrestrial Laser Scanner (TLS) Trimble X7 laser scanner, generating a 3D point cloud that models the bridge surface with precise spatial coordinates. The methodology utilizes the reflective intensity of the laser pulses to obtain quantitative information about the surface. This approach allows for the precise identification, demarcation, and quantification of deteriorated areas. The application of this methodology facilitates a non-invasive and detailed diagnosis of the surface condition, providing quantitative and visual information that can enhance the maintenance planning of critical infrastructure such as pedestrian bridges.
A. E. Escobedo Tamez, Nallely Salazar González, F. D. Yépez Rincón et al.· The International Archives o...· 0 citations
In the context of the continuous growth of railway transportation volume, the safe operation and maintenance of train carriages have placed higher demands on the accuracy and efficiency of damage detection. Traditional detection methods are unable to effectively quantify various types of damage such as corrosion, dents, and surface deformations on the carriages. The digital detection technology based on 3D reconstruction provides a new approach to this problem. However, most existing 3D reconstruction methods rely on multi-view registration, which has the drawbacks of complex processes and long time consumption, making it difficult to meet the actual requirements of rapid detection during train operation. Therefore, this paper proposes a lightweight single-station laser radar reconstruction method without multiview registration. The comparative experiments conducted on four different types of carriages have verified that the comprehensive performance of this method is excellent. The BPA algorithm is prone to surface overfitting and loss of key features, while the Alpha-shape algorithm is prone to generating small holes, disordered structures, and poor noise resistance. The minimum Chamfer distance (CD) of this method can reach 0.006346 millimeters, the point-to-grid distance (PTD) is stable between 0.098 and 0.227 millimeters, and the reconstruction time is controlled within 5.34 to 6.38 seconds. This method demonstrates excellent feasibility and applicability in 3D reconstruction of train carriages, and can provide an efficient and feasible technical solution for the digital detection and intelligent maintenance of train carriages.
Linbo Liu, Hongtao Wang, Zhijia Zhang et al.· International Conference on...· 0 citations
Abstract. The 3D documentation of complex scenes—characterized by restricted spaces, irregular geometries, and poor lighting—remains a significant challenge in cultural heritage. This study proposes a rapid data acquisition methodology based on the multi-sensor fusion of Terrestrial Laser Scanning (TLS) and Spherical Photogrammetry (SP). The approach was validated in two distinct complex environments: an ancient Egyptian rock-cut tomb (QH36, Aswan, Egypt) and a natural Iberian sanctuary cave (Cueva de la Lobera, Jaén, Spain). The methodology uses TLS to establish a high-precision geometric backbone, achieving registration errors below 0.5 cm. By extracting Ground Control Points (GCPs) directly from the TLS point cloud, the reliance on traditional total station surveying was significantly reduced, enhancing fieldwork efficiency. SP was implemented to obtain realistic textures and to support geometry by using a 360-degree multi-camera with integrated LED lighting, providing full spherical coverage and high-resolution textures. Results indicate that SP is at least six times faster than conventional photogrammetry. Furthermore, the use of TLS-derived meshes enabled advanced digital masking to remove non-interest objects (e.g., archaeological equipment) from the final models. While conventional photogrammetry remains the benchmark for fine architectural details, this research demonstrates that the TLS-SP fusion is the most viable solution for the rapid, high-accuracy documentation of constrained heritage sites. This hybrid workflow ensures geometric integrity while drastically reducing acquisition times, providing a robust framework for future archaeological and conservation projects.
A. Mozas-Calvache, José Luis Pérez-García, J. M. Gómez-López et al.· The International Archives o...· 0 citations
Abstract. Structural health monitoring of bridge infrastructure is conventionally carried out either through the acquisition of data from embedded sensor arrays or through systematic inspection and documentation of surface-observable changes on the structure. External deterioration, such as crack formation or load-induced structural deformations, is typically identified during these inspections. However, conventional visual inspections are often labor-intensive and costly. Automated, camera-based photogrammetric monitoring methods offer a promising alternative to reduce both effort and expense. For the specific task of detecting vertical deformations in a bridge superstructure, a tripod-stabilized mono camera setup can be utilized. This approach enables the derivation of vertical deformations by tracking the displacement of target points within a predefined measurement field over time. This study investigates the derivation of vertical deformations from image sequences. Using a representative test bridge as a case study, the characteristic vertical deformation response induced by the traversal of a loaded vehicle is analyzed and documented. A measurement point field was affixed to the bridge superstructure and continuously observed. From the acquired image sequences, continuous vertical displacements were successfully derived, with a mean vertical deflection of the bridge superstructure in the range of −1.71 mm to +0.72 mm. The mean measurement noise, averaged across all monitored test cycles, amounted to 0.01 mm. The results demonstrate that high-quality deformation data can be acquired in a cost-efficient manner using a consumer-grade camera in conjunction with a standardized measurement field, thereby offering a viable low-cost alternative to conventional structural monitoring instrumentation.
R. Blaskow, H. Sardemann, Hans-Gerd Maas· The International Archives o...· 0 citations
