Quality Evaluation of Digital Twins Generated Based on UAV Photogrammetry and TLS: Bridge Case Study

Abstract

In the current modern era of information and technology, emerging remote advancements have been widely established for detailed virtual inspections and assessments of infrastructure assets, especially bridges. These technologies are capable of creating an accurate digital representation of the existing assets, commonly known as the digital twins. Digital twins are suitable alternatives to in-person and on-site based assessments that can provide safer, cheaper, more reliable, and less distributive bridge inspections. In the case of bridge monitoring, Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are among the most common advanced technologies that hold the potential to provide qualitative digital models; however, the research is still lacking a reliable methodology to evaluate the generated point clouds in terms of quality and geometric accuracy for a bridge size case study. Therefore, this paper aims to provide a comprehensive methodology along with a thorough bridge case study to evaluate two digital point clouds developed from an existing Australian heritage bridge via both UAV-based photogrammetry and TLS. In this regard, a range of proposed approaches were employed to compare point clouds in terms of points’ distribution, level of outlier noise, data completeness, surface deviation, and geometric accuracy. The comparative results of this case study not only proved the capability and applicability of the proposed methodology and approaches in evaluating these two voluminous point clouds, but they also exhibited a higher level of point density and more acceptable agreements with as-is measurements in TLS-based point clouds subjected to the implementation of a precise data capture and a 3D reconstruction model.

Fresh, Mechanical, and Durability Properties of Self-Compacting Mortar Incorporating Alumina Nanoparticles and Rice Husk Ash

“…The chemical composition of NA is reported in Table 2. Previous research studies have stated that the quality of water can also affect the properties of concrete and cementitious materials [5,[35][36][37][38][39][40][41][42]. However, in this research, distilled and tap water were respectively used for the characterization tests and for sample preparation studies according to the recommendation of some previous studies [43][44][45][46][47][48][49][50][51][52].…”

Datenmodelle für digitale Zwillinge von Brücken und bildbasierte Zustandsaufnahmen

“…Zum einen werden Ansätze entwickelt, Punktwolken aus Laserscan oder fotogrammetrischer Rekonstruktion in den Bauwerkskontext zu überführen und durch Bauteilsemantik zu klassifizieren [5]. Ebenso werden Punktwolken zur Analyse von Verformungen [6][7][8] oder zur Kontrolle der modellierten Geometrie [9] genutzt. Zum anderen werden die Zustandsdaten genutzt, um die Detektion von Anomalien an der Bauwerksoberfläche zu unterstützen.…”

Application of Terrestrial Laser Scanning (TLS) in the Architecture, Engineering and Construction (AEC) Industry

“…3D point clouds are currently most commonly acquired by a terrestrial laser scanner. However, several limitations are found in TLS applications, such as the high equipment cost and the restricted access [ 229 ]. Several studies have been conducted on different techniques and tools for obtaining detailed point clouds in the AEC industry, including laser scanning, photogrammetry, and videogrammetry, as explained in the following.…”

“…The traditional photogrammetric instruments include single-lens cameras, stereo cameras, RGB-D cameras, etc. Due to the advancement of camera technology and image processing algorithms in recent years, smartphone-based [ 235 , 236 , 237 ] and UAV-based [ 229 , 238 , 239 , 240 , 241 , 242 ] acquisition methods of point clouds have been developed and applied. The key benefit of most photogrammetric instruments is real-time acquisition (portable and flexible) at low cost.…”