Application Of Terrestrial Laser Scanning Research Articles

THE FEATURES OF SPORTS COMPLEX 'SUNKAR' MONITORING BY TERRESTRIAL LASER SCANNING

Abstract. The paper is aimed at the study of monitoring workflow in adverse observation conditions for sports structures. The application of terrestrial laser scanning for monitoring various objects is well-studied. However, the deployment of TLS for large sports structures is challenging. Such structures have huge sizes, complex geometry and need the control of particular elements. The monitoring gets complicated in the case when the structure is placed on a very steep slope, e.g., ski jumps or bobsleigh tracks. The subject of the presented study is the complex of ski jumps 'Sunkar' emplaced in Almaty, Republic of Kazakhstan. The monitoring network for the complex was created using a robotic total station. Due to the extreme sizes of the object (height 70 m, width 8 m, length over 100 m), TLS was accomplished from all points of the network to ensure the necessary density of point clouds and reliable georeferencing. The main observation parameters were the displacements of the ski jumps regarding the longitudinal axis. To retrieve the axis coordinates, the point cloud was sliced along the ski jump surface. The geometry of the longitudinal axis was simulated using spline functions. As an output, the suggested monitoring workflow is provided that ensures the quality of the necessary results.

Application of Terrestrial Laser Scanning in Inventories of Architectural Objects and Building Structures – Illustrated by St. Lazarus’ Church in Wrocław (Poland)

Laser scanning technology is currently one of the most popular geodetic measurement methods, used for example in preparing inventories of architectural objects and of building structures. Its advantage results from high measurement effectiveness (the possibility to acquire large amounts of data in a relatively short period of time), precision and “resistance” to environmental conditions (the ability to make measurements independently of light or wind conditions, also during light rain or in the presence of limited amounts of dust in the air). This paper presents a method for using the Autodesk Revit environment to construct a 3D model of St. Lazarus’ Church in Wrocław. The model is based on data acquired from in-field measurements using Terrestrial Laser Scanning (TLS). The paper also presents a methodology for the acquisition and processing of such data and includes an evaluation of the precision of both the data and the resulting 3D model. The final result of the presented research comprises a 3D model of St. Lazarus’ Church in Wrocław, together with 2D documentation.

Static Terrestrial Laser Scanning (TLS) for Heritage Building Information Modeling (HBIM): A Systematic Review

Heritage Building Information Modeling (HBIM) is an essential technology for heritage documentation, conservation, and management. It enables people to understand, archive, advertise, and virtually reconstruct their built heritage. Creating highly accurate HBIM models requires the use of several reality capture tools, such as terrestrial laser scanning (TLS), photogrammetry, unmanned aerial vehicles (UAV), etc. However, the existing literature did not explicitly review the applications and impacts of TLS in implementing HBIM. This paper uses the PRISMA protocol to present a systematic review of TLS utilization in capturing reality data in order to recognize the status of applications of TLS for HBIM and identify the knowledge gaps on the topic. A thorough examination of the 58 selected articles revealed the state-of-the-art practices when utilizing static TLS technology for surveying and processing captured TLS data for developing HBIM models. Moreover, the absence of guidelines for using static TLS surveys for HBIM data acquisition, the lack of robust automated frameworks for producing/transferring 3D geometries and their attributes from TLS data to BIM entities, and the under-utilized application of TLS for long-term monitoring and change detection were identified as gaps in knowledge. The findings of this research provide stakeholders with a good grasp of static TLS for HBIM and therefore lay the foundation for further research, strategies, and scientific solutions for improving the utilization of TLS when documenting heritage structures and developing HBIM.

Topology-based individual tree segmentation for automated processing of terrestrial laser scanning point clouds

Terrestrial laser scanning (TLS) is a ground-based approach to rapidly acquire 3D point clouds via Light Detection and Ranging (LiDAR) technologies. Quantifying tree-scale structure from TLS point clouds requires segmentation, yet there is a lack of automated methods available to the forest ecology community. In this work, we consider the problem of segmenting a forest TLS point cloud into individual tree point clouds. Different approaches have been investigated to identify and segment individual trees in a forest point cloud. Typically these methods require intensive parameter tuning and time-consuming user interactions, which has inhibited the application of TLS to large area research. Our goal is to define a new automated segmentation method that lifts these limitations. Our Topology-based Tree Segmentation (TTS) algorithm uses a new topological technique rooted in discrete Morse theory to segment input point clouds into single trees. TTS algorithm identifies distinctive tree structures (i.e., tree bottoms and tops) without user interactions. Tree tops and bottoms are then used to reconstruct single trees using the notion of relevant topological features. This mathematically well-established notion helps distinguish between noise and relevant tree features. To demonstrate the generality of our approach, we present an evaluation using multiple datasets, including different forest types and point densities. We also compare our TTS approach with open-source tree segmentation methods. The experiments show that we achieve a higher segmentation accuracy when performing point-by-point validation. Without expensive user interactions, TTS algorithm is promising for greater usage of TLS point clouds in the forest ecology community, such as fire risk and behavior modeling, estimating tree-level biodiversity structural traits, and above-ground biomass monitoring.

Application of Terrestrial Laser Scanning for the Evaluation of Geokinematics of Selected Structural Phenomena in Mine Workings in the Rudna Mine (SW Poland)

Application of Terrestrial Laser Scanning for the Evaluation of Geokinematics of Selected Structural Phenomena in Mine Workings in the Rudna Mine (SW Poland)

Multisource forest point cloud registration with semantic-guided keypoints and robust RANSAC mechanisms

• The proposed method was independent of single tree detection and ground filtering. • A new type of keypoint was proposed for forest point cloud registration. • Robust RANSAC mechanism was introduced to enhance registration performance. The Increasing availabilities of Terrestrial Laser Scanning (TLS) and Unmanned Aerial Vehicle Laser Scanning (ULS) have advanced accurate and detailed forest structural measurements. Registration of multi-perspective observations from different platforms is a prerequisite for a comprehensive forest structure understanding. Currently, forest point cloud registrations are typically done by single tree attribute-based (e.g. tree location, stem diameter) methods, which suffer from various and complex forest compositions and terrains, and can be unreliable for forests with regular tree layouts and insufficient common trees. Therefore, this study presents a unified and marker-free framework for both TLS-TLS and ULS-TLS point cloud registrations in forest areas. First, motivated by wood-leaf separation, semantic-guided keypoints from TLS and ULS point clouds are detected by utilizing a wood response indicator (WRI), which represents reliable repeatability between different views of forest point clouds. Second, an initial correspondence set is generated by using the WRI filter and Binary Shape Context (BSC) descriptor matching. Finally, the initial correspondence set is trimmed and optimized through a robust RANSAC mechanism, consisting of a geometric compatibility filter to guide and trim the hypothesis generation process and a modified hypothesis evaluation step to further optimize the transformation. Experiments have been conducted on six plots involving diverse stem densities and tree species located in forest farms in Guangxi, China. The resulting average registration residual and runtime are 0.049 m and 93 s for TLS-TLS scenes, 0.299 m and 242 s for ULS-TLS scenes, respectively. Comprehensive comparisons demonstrate that the proposed method outperforms other baselines. It is demonstrated that the proposed framework can improve the practicality and efficiency of multi-source data collection and registration, thus facilitating the application of TLS and ULS in forest ecosystem science.

Cost–Benefit Analysis of Scan-vs-BIM-Based Quality Management

Terrestrial laser scanning (TLS) and building information modeling (BIM) play an important role as smart construction technologies introduced to increase productivity in the architecture, engineering, and construction (AEC) industry. However, these smart construction technologies have not been well introduced due to their high initial investment cost and poor performance reliability. Therefore, this study presents the results of a cost–benefit analysis to prove the investment value of terrestrial laser scanning and building information modeling. First, the reliability of this study data was increased through a case analysis of a real-world multi-project conducted by a single organization. Second, this study quantitatively proposed the economic value of terrestrial laser scanning and building information modeling by applying cost–benefit analysis (CBA). The effects of the application of terrestrial laser scanning and building information modeling on manpower input and time reduction were quantitatively analyzed through the cost–benefit analysis. The results showed that the cash value flows of terrestrial laser scanning and building information modeling could be considered to make value-for-money decisions for the adoption of terrestrial laser scanning and building information modeling in construction engineering organizations.

An adaptive grid search algorithm for fitting spherical target of terrestrial LiDAR

The spherical target is critical in many terrestrial laser scanning applications. Accurately and robustly estimating its geometric center based on a point cloud is a problem of widespread concern. To address this problem, we propose a novel adaptive grid search (AGS) algorithm, which makes full use of the point cloud and geometric feature of the spherical target, and obtains the optimal fitting parameters through a finite number of iterative optimizations. Firstly, we utilize the centroid of the point cloud and the estimated radius of the spherical target as constraints to establish an initial constraint space. Secondly, we use grid search to determine the initial optimal solution of the parameters. Finally, we iteratively update the constraint space and the optimal solution utilizing the previous optimal solution and the parameters scales, and take the solution with the least error metric as the final optimal solution. We have validated the feasibility and reliability of the algorithm with actual data and simulated data, respectively, and compared the fitting results with those of the Non-Least Squares algorithm (NLS) and the M−estimator SAmple Consensus (MSAC) algorithm. The experimental results show that the AGS algorithm can achieve high-precision fitting of various point clouds of spherical targets and overcome the defects of the other two algorithms that are easily affected by noise and coverage. Due to iterative optimization, the running time of the AGS algorithm is slightly longer than the other two algorithms, but it can usually complete the fitting within 5 s.

THE CAPABILITIES OF 3D GEOSPATIAL TECHNOLOGIES IN THE DECISION-SUPPORT PROCESS FOR DESIGN, CONSTRUCTION, AND EMPLOYMENT OF ENGINEERING STRUCTURES

Abstract. The presented paper is concerned with the capabilities of 3D geospatial technologies in the decision-support process for the design, construction, and employment of engineering structures. Among the various geospatial technologies, the primary stress is made on terrestrial laser scanning (TLS). Despite the widespread application of TLS, its opportunities are not studied thoroughly. A vast volume of studies is dedicated to accuracy, processing workflow, and modeling by TLS data. However, only scanty research considers the TLS technology and data from an ordinary civil engineer's point of view. This study attempts to fill this gap. Covered topics are analysis of the current trends of measurement technologies; in-depth analysis of laser scanning results as a source of new unique data; laser scanning for industrial applications; laser scanning and BIM integration. Except for the mentioned topics, the new concept of the complete control of geometric parameters during the construction and operation of engineering structures is introduced. Complete control plays an indispensable role in the decision-support process during the building life cycle and therefore is an inherent part of any BIM. A description of the steps of complete control and its different applications for civil engineering is given. The decision-support process is addressed for different structures, e.g., roads, civil and industrial structures, oil and gas industry objects, etc. Moreover, complete control is considered for the various stages of a building life cycle, from design to demolition. The results provide convincing evidence that the complete control by TLS data has a prominent role in the decision-support process for civil engineering.

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

As a revolutionary technology, terrestrial laser scanning (TLS) is attracting increasing interest in the fields of architecture, engineering and construction (AEC), with outstanding advantages, such as highly automated, non-contact operation and efficient large-scale sampling capability. TLS has extended a new approach to capturing extremely comprehensive data of the construction environment, providing detailed information for further analysis. This paper presents a systematic review based on scientometric and qualitative analysis to summarize the progress and the current status of the topic and to point out promising research efforts. To begin with, a brief understanding of TLS is provided. Following the selection of relevant papers through a literature search, a scientometric analysis of papers is carried out. Then, major applications are categorized and presented, including (1) 3D model reconstruction, (2) object recognition, (3) deformation measurement, (4) quality assessment, and (5) progress tracking. For widespread adoption and effective use of TLS, essential problems impacting working effects in application are summarized as follows: workflow, data quality, scan planning, and data processing. Finally, future research directions are suggested, including: (1) cost control of hardware and software, (2) improvement of data processing capability, (3) automatic scan planning, (4) integration of digital technologies, (5) adoption of artificial intelligence.

Characterizing subcanopy structure of Mediterranean forests by terrestrial laser scanning data

Vegetation structure is one of the key factors in forest ecosystems. Especially understory structure has major implications for wildlife habitat selection, reproduction, and survival. Structural indices traditionally used to characterize understory vegetation are based on field vegetation surveys describing general features such as leaf area index (LAI), canopy cover or vegetation height, hiding much of the three-dimensional vegetation structure complexity. The application of terrestrial laser scanning (TLS) in forest ecological and management applications is becoming more effective. In this study, we use TLS data to quantify spatial attributes of forest subcanopy in four different forest strata ranging from 0.5 m to 10 m from the ground. We collected data in 12 plots of mature European beech (Fagus sylvatica L.) forests and 12 plots of mature black pine (Pinus nigra subsp. laricio Maire) forests, located in the Sila National Park, Italy. We propose a TLS-based approach to estimate a fine-scale vegetation density using the Plant Density Index (PDI) and to test the PDI at different height classes. We found a significant relationship between the PDI and the number of trees belonging to the dominant layer, using the Spearman correlation coefficient (r = 0.83, pval = 0.001). Basing on PDI values, a cluster analysis of the four subcanopy strata was carried out for deriving clusters of structurally homogeneous forest plots. Results identified three clusters in terms of the vegetation features in the horizontal height classes: the first cluster primarily includes Beech forests characterized by plots with the highest tree densities; the second one includes both Beech and Pine forests characterized by dense ground vegetation and shrubs and an intermediate tree density; the third group is represented by Pine forests with massive presence of vegetation lower strata and moderate tree density. Then, PCA allowed identifying the relationship between the considered subcanopy layers and forest plots.

Application of Terrestrial Laser Scanning for the Inventory of Historical Buildings on the Example of Measuring the Elevations of the Buildings in the Old Market Square in Jarosław

Terrestrial laser scanning (TLS) technology is increasingly used in surveying, construction and architecture. The potential of the data obtained by this method creates the possibility of its versatile application also in conservation and revitalization of monuments, archaeology or history. The use of this technology during the creation of architectural documentation of a historic building greatly facilitates the acquisition of comprehensive information about its actual condition in a fast, non-invasive and very precise manner. Thanks to digital technology, it also creates the possibility to accurately interpret the condition of an object and present its model in a virtual space. This technology provides the ability to transfer acquired image elements with high accuracy of their mapping to plans and designs prepared by architects and contractors. It is also possible to maintain high technical standards in the processes aimed at the preparation of the required graphical studies, thanks to the use of the point cloud obtained in TLS. One of the most important advantages of using this measurement method is the possibility of combining it with data from e. g. from photogrammetric tools, which gives the possibility to fill in the missing elements creating a more complete picture of the needed data. This paper presents the implementation of terrestrial laser scanning technology as a non-invasive method for the modelling of walls and buildings of the so-called “greenfield”. Revers BIM on the example of the measurement of the facades of the buildings of the old market in Jarosław. This technology allows for preparation of precise architectural documentation including: projections, sections, elevation views, 3D models or multimedia visualizations. The use of TLS for cultural heritage research also enables the preparation of fully complete documentation for conservation and restoration works aimed at maintaining the current state of monuments or even at reconstructing their damaged architectural elements.

Dynamic characterization of a slow-moving landslide system – Assessing the challenges of small process scales utilizing multi-temporal TLS data

Slow-moving landslides play an important role in both theoretical slope evolution and practical landslide hazard and risk research. Related dynamics therefore are of major interest, including the investigation of surficial changes. Yet, very slow process rates impede their quantitative analysis over short time periods, the actual change not uncommonly lying within the error margins of the respective methodological approaches. This study aims in investigating the surface dynamics of a small, retrogressive, slow-moving (cm-dm/a) earth slide-earth flow system in the Flysch Zone of Lower Austria via multi-temporal, high-resolution terrestrial laser scanning (TLS) data. 7 epochs covering a 10 years' observation period were utilized to apply both detailed morphological mapping and the computation of digital elevation models (DEMs) of difference (DoDs). Data was analysed to 1) determine and delineate (recently active) process areas, 2) to describe their characteristics, rates and tendencies comparatively via mapping and DoDs - but also 3) to assess the applicability of TLS regarding vegetation cover and to 4) evaluate the added value of this comparative approach when it comes to interpreting landslide dynamics on such detailed scale. Two small Subsystems of the respective landslide, I (~3300 m2) and II (2100 m2), exhibit the highest activity within the observation period. Results show 1) areas of changes in surface height correspond with changes in the distribution and characterization of morphological landslide features, indicating landslide activity. 2) Both Subsystems exhibit different results regarding the magnitude of changes in surface height (DoDs) and feature assembly (mapping), but show similarity regarding the frequency of both changes in surface height and feature evolution, identifying them as rotational and translational process types interrelated with the main landslide system. 3) Findings suggest TLS based DoD computations to be able to detect real surface change on detailed scale (0.05 m raster, ±0.05 error range, 0.05 m steps) in areas of optimum conditions regarding vegetation cover, but also that 4) real surface change could be assessed in areas of less optimum conditions (±020 m error range, 0.20 m steps) where real surface change was overshadowed by changes in vegetation cover via comparatively analysing both DoD and mapping results.

Voxel Grid-Based Fast Registration of Terrestrial Point Cloud

Terrestrial laser scanning (TLS) is an important part of urban reconstruction and terrain surveying. In TLS applications, 4-point congruent set (4PCS) technology is widely used for the global registration of point clouds. However, TLS point clouds usually enjoy enormous data and uneven density. Obtaining the congruent set of tuples in a large point cloud scene can be challenging. To address this concern, we propose a registration method based on the voxel grid of the point cloud in this paper. First, we establish a voxel grid structure and index structure for the point cloud and eliminate uneven point cloud density. Then, based on the point cloud distribution in the voxel grid, keypoints are calculated to represent the entire point cloud. Fast query of voxel grids is used to restrict the selection of calculation points and filter out 4-point tuples on the same surface to reduce ambiguity in building registration. Finally, the voxel grid is used in our proposed approach to perform random queries of the array. Using different indoor and outdoor data to compare our proposed approach with other 4-point congruent set methods, according to the experimental results, in terms of registration efficiency, the proposed method is more than 50% higher than K4PCS and 78% higher than Super4PCS.

Detection of seasonal changes in vegetation and morphology on coastal salt marshes using terrestrial laser scanning

Coastal salt marshes exhibit strong seasonal variations that may induce subsequent changes in their morphology. However, such changes are insufficiently understood due to a lack of data at seasonal timescales. Knowledge of the seasonal variability is essential for coastal management and ecosystem conservation. Terrestrial laser scanning (TLS) technology allows the rapid acquisition of high-resolution and large-scale vegetation and morphology data with an error of <3 cm. In this study, we used a TLS system to retrieve high-accuracy digital canopy models (DCM) for low vegetation species (approximately 20 cm) Suaeda salsa and digital terrain models (DTM) of a marsh in the Yellow River Delta. We conducted three TLS surveys on the same field on January 5, April 21, and November 20, 2019, which spanned from the dry to wet seasons. The centimeter-scale TLS data retrieved the seasonal variations of vegetation and elevation distributions. The DCMs of the study area showed that the percentages of vegetation-occupied regions were 13.5% and 22.5% in the dry and wet seasons, respectively. The DTMs indicated a net erosion of the study area throughout the year, but at a larger erosion rate in the dry than the wet season, that is, a rate of 2.5 and 0.2 cm/month, respectively. Spatially, regions with vegetation and zones adjacent to creeks underwent slight deposition. We inferred that the larger riverine sediment supply and higher vegetation density in the wet (summer) season mitigated erosion, while the influence of rich sediment supply was crucial. This work demonstrates the applicability of TLS in detecting the distribution of low-height vegetation species, and quantifying vegetation and morphological changes of marshes at seasonal timescales owing to its high resolution.

Application of Terrestrial Laser Scanning to Determine Deformations - Practical Aspects

When using laser scanning for deformation analysis of a given object, there are no pre-signalled points or identical points to compare between two epochs, so we can judge for whether an object deforms only by modelling the surface of the object. There are a number of challenges in this regard presented in the paper. The first challenge is that for the deformation analysis the configuration of the measurement parameters is no longer set by the surveyor-engineer by the number and position of the observed points, but from the laser scanner. Only the location of the scanner and the scanning density could be controlled. The second challenge is to expand the error model, as the surface modelling is included in the deformation process. This unifies both the metrological and the model errors that arise from the insufficient knowledge of the object and the simplification of its surface. All these challenges are oriented to the created 3D surface model. In addition, the metrological aspects of the use of laser scanners should be considered, especially for applications where the determination of the deformation requires high accuracy. A number of conclusions and recommendations are formulated. The influence of the factors influencing the accuracy of ground laser scanning in the deformation study is summarised, and the influence of the external orientation ang georefering of the point cloud on the accuracy of the digital model is established. Preliminary assessment of the accuracy of the TLS results are given. Justification of the reliability of the determined deformations through TLS is presented. Technological scheme and recommendations for determination of deformations with TLS is shown.

Application of terrestrial laser scanning in forest inventory – an overview of selected issues

AbstractPrecise determination of forest resources is one of the most important tasks in conducting sustainable forest management. Accurate information about the forest’s resources allows for a better planning of current and future management as well as conservation activities. Such precise information is needed by both, individual forest managers and for developing the national forest policy. In recent years, interest in the use of remote sensing in forest inventory has significantly increased. Remote sensing allows for non-invasive measurements and the automation of data processing. The most accurate source of remote sensing data at the level of the sample plot is terrestrial laser scanning (TLS). Its use in forest inventory has been studied for about two decades.This paper aims to introduce studies on state of the art TLS technology as well as provide an overview of research conducted in stands within the temperate climate zone. This article furthermore discusses issues such as TLS data acquisition, data processing and presents results for the estimation of tree biometric features.

Beam Deflection Monitoring Based on a Genetic Algorithm Using Lidar Data.

The Light Detection And Ranging (LiDAR) system has become a prominent tool in structural health monitoring. Among such systems, Terrestrial Laser Scanning (TLS) is a potential technology for the acquisition of three-dimensional (3D) information to assess structural health conditions. This paper enhances the application of TLS to damage detection and shape change analysis for structural element specimens. Specifically, estimating the deflection of a structural element with the aid of a Lidar system is introduced in this study. The proposed approach was validated by an indoor experiment by inducing artificial deflection on a simply supported beam. A robust genetic algorithm method is utilized to enhance the accuracy level of measuring deflection using lidar data. The proposed research primarily covers robust optimization of a genetic algorithm control parameter using the Taguchi experiment design. Once the acquired data is defined in terms of plane, which has minimum error, using a genetic algorithm and the deflection of the specimen can be extracted from the shape change analysis.

Analysis of stand density effects on the stem form of Norway spruce trees and volume miscalculation by traditional form factor equations using terrestrial laser scanning (TLS)

Tree and stand volume estimates are relevant for forest inventories, forest sales, and carbon stock evaluations. Forest practice commonly uses generalized stem-wood volume functions; however, such generalized approaches neglect the stem form in detail. Hence, trees of a given species with the same diameter at breast height (d1.3) and height (h) are always assumed to have the same form factor and thus the same volume. This case study focused on stem form variation of Norway spruce (Picea abies (L.) Karst.) due to competition effects. Using terrestrial laser scanning (TLS), we measured the stem shape of 868 trees from a long-term spacing and thinning experiment in Germany. The plots covered a broad density range. We analysed the effect of competition and compared the TLS-determined stem volume estimates with those determined conventionally. TLS-based volume estimations showed that the lower the competition was, the lower the tree volume was with a given d1.3 and h. Commonly used functions underestimated the volume stock overall by 4.2%, disregarding any levels. At plot level, underestimation varied from 0.7% to 7.0%. At tree level, the volume was under- and over-estimated by −10% to +10%, respectively. The more precise the examination was, the more suitable the application of TLS was for enhancing volume estimation.

Diagnostic utilisation of ground based imaging and non-imaging sensors for digital documentation of heritage sites

Historical buildings are essential elements of cultural heritage. Built-up heritage is subjected to various damages over a long period of time, and it is, therefore, necessary to document such monuments by using multiple sensors, which are not only efficient but also non-complicated and effortless in terms of data acquisition and handling. Complete documentation of the monument involves recognition and mapping of such damages, if present. As the monuments are of considerable sizes and sometimes not easily accessible, recording and mapping of the damages by manual methods is both time-consuming and costly. Terrestrial laser scanning (TLS), combined with terrestrial images, can be used to document and map damages of the monuments. The present work demonstrates the practical application of TLS in the documentation of heritage monuments with a focus on damage detection using TLS point clouds and terrestrial optical data.