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Fully automatic approach for the diagnosis of masonry arches from laser scanning data and inverse finite element analysis
Published in Koen Van Balen, Els Verstrynge, Structural Analysis of Historical Constructions: Anamnesis, Diagnosis, Therapy, Controls, 2016
B. Riveiro, B. Conde, G.A. Drosopoulos, G.E. Stavroulakis, M.E. Stavroulaki
Laser scanning is a geomatic method that allows obtaining 3D geometry of objects' surface in an automatic way by using LiDAR technology. Different classifications are standardized for laser scanning attending to different principles used for distance measurement (Vosselmann and Maas, 2010). For civil engineering applications the most common method is based onmeasuring the time of flight (TOF) of the laser beam. This principle allows distances to be remotely computed by measuring the time delay between the emission and return of a laser beam that travels from the instrument (a laser scanner) to the object. This distance may be obtained directly, by using short repetitive laserpulses, orindirectly by modulating the power of the wavelength of the laser beam and using phase difference (Vosselmann and Maas, 2010).
Review of UNESCO’s World Heritage Nomination Files (WHNF), Building Information Modelling (BIM) and Heritage Building Information Modelling (HBIM)
Published in Ahmad Baik, Heritage Building Information Modelling for Implementing UNESCO Procedures, 2020
Laser scanning is an advanced technology which can provide highly accurate data. According to Murphy (2012) using laser scanning and photogrammetry in the case of capturing the heritage structure can “meet with the accuracy and efficiency requirements for recording and surveying of historic structures and arte-facts”. However, accuracy can be affected by various factors, for example errors in the distance and the angle measurements, and in the algorithm for fitting the “spheres/targets” in the point cloud. Unfortunately, according to Mechelke et al. (2007), “the influence of these errors cannot be determined separately”. Moreover, some laser scanning equipment can have issues through reflectance out of certain materials like marble and gilded façades.
A 3D laser scanning technique and its application to rock mechanics and rock engineering
Published in Xia-Ting Feng, Rock Mechanics and Engineering, 2017
Laser scanning not only measures the position but also the reflective intensity at every point, so that the laser image created is based upon the intensity difference between different objects. Because different rocks have different intensities, the intensity laser image has been studied in order to identify different rock types. In this study, several image processing methods were tested, such as texture analysis and image classification. Figure 10 shows different rock types in a pseudo-color laser image created by these methods.
TLS and FEM combined methods for deformation analysis of tunnel structures
Published in Mechanics of Advanced Materials and Structures, 2022
Hao Yang, Xunqian Xu, Xiangyang Xu, Wei Liu
A structural health monitoring system contains various common nondestructive technologies, such as optical sensors [1], wireless sensors [2], multi-sensors [3], inter alia [4]. A system for three-dimensional (3D) surface measurement was proposed based on vision sensing to gain image-based surfaces [5]. Laser sensing was developed in various applications, for example, monitoring of structures, navigation and manufacturing. Regarding the monitoring applications, the benefits of laser scanning is the massive and full-field data, which can capture the characteristics of the structures comprehensively, overpassing the traditional point-wise measurements. The laser scanning technology characterizes the real structures with massive 3D points of structural surface. It is a non-contact 3D point cloud collection method with high efficiency, precision and resolution. The laser scanning technology is currently widely used for monitoring various constructions, such as tunnels, bridges and rails. The usability of laser scanning technology applied in rail track inspection has been demonstrated in some advanced track inspection vehicles. Structural health monitoring systems are very important for tunnel construction, especially for deformation control and stability analysis [6].
Vision-based load sway monitoring to improve crane safety in blind lifts
Published in Journal of Structural Integrity and Maintenance, 2018
Yihai Fang, Jingdao Chen, Yong K. Cho, Kinam Kim, Sijie Zhang, Esau Perez
Laser scanning is a non-intrusive sensing technology that rapidly and accurately captures the 3D shape of physical objects in the format of a point cloud. To help equipment operators rapidly perceive the crane pose and surrounding environment, Cho and Gai (2014) introduced a dynamic object recognition and registration method using laser scanning technology. The 3D point cloud is projected to a 2D space where the geometric features represented by a local SURF descriptor are compared to a prepared template database for recognition. This method is effective and efficient for recognizing target objects that are known to be present on the construction site. Wang and Cho (2015) proposed a smart scanning technique for tracking the location and pose of mobile cranes. By updating the crane’s point cloud data while keeping the previously scanned static workspace data, this method greatly improves the modeling and updating rate, which makes it suitable for real-time visualization and decision-making support. Another benefit of laser scanning-based approaches is that it is non-invasive, meaning that there is no need to deploy any sensors or devices on the equipment. Instead, it requires a data acquisition system to operate in close proximity to the equipment, and computational power constraints in real-time data processing and transmission.
Condition assessment of rigid pavement using terrestrial laser scanner observations
Published in International Journal of Pavement Engineering, 2022
Ashraf A. A. Beshr, Osama G. Heneash, Hossam El-Din Fawzy, Mona M. El-Banna
Nowadays, the laser scanning technology is used besides Close Range Photogrammetry (CRP) and instead of traditional methods. Advances in digitisation lead to significant development in surveying and image processing technologies. Digital image processing techniques have spread in many fields in civil engineering such as (Photogrammetry, laser scanners, robotic equipment, etc.) (Beshr 2012). There are several methodologies for monitoring reinforced concrete structures or paving roads (Galantucci and Fatigues 2019). The ground-based laser scanner allows creating a spot cloud network through three stages of the proposed three-dimensional (3D) scanning process and combining them with the program, and it also allows to measure the internal and external details of the object by scanning them as point series in horizontal and vertical directions, under a specific angle and it is considered one of the most widely used imaging measurement techniques and obtaining sequential images (objects or scenes) and measure a 3D model (Barbieri and Pinto 2019). A field procedure was proposed for a laser ground scanner while the surveyor data and calculation plan were obtained from defect size determination and measurement (Maurizio and Fabrizio 2017). Laser scanning was used because of its safety, as it reduces risks associated with climbing, burns to chemical exposure and reduces time required in process area for data collection. It can significantly reduce field time and reduces accuracy errors associated with traditional field measurements. The amount of data collected exposes more potential clashes and conflicts thus mitigating hits to the budget.