Use Of Terrestrial Laser Scanner Research Articles

Laser scanner and UAV digital photogrammetry as support tools for cosmic-ray muon radiography applications: an archaeological case study from Italy

The use of light detection and ranging technologies, i.e. terrestrial laser scanner (TLS), airborne laser scanner (ALS) and mobile laser scanner (MLS), together with the unmanned aerial vehicles digital photogrammetry (UAV-DP) and satellite data are proving to be fundamental tools to carry out reliable muographic measurement campaigns. The main purpose of this paper is to propose a workflow to correctly plan and exploit these types of data for muon radiography aims. To this end, a real case study is presented: searching for hidden tombs in the Etruscan necropolis of Palazzone (Umbria, Italy). A high-resolution digital elevation model (DEM) and three-dimensional models of the ground surface/sub-surface of the study area were created by merging data obtained using different survey methods to achieve the most accurate three-dimensional environment. Indeed, the simulated muon flux transmission used to infer relative transmission values, and the estimated density distribution, depends on the reliability of the three-dimensional reconstructed ground surface model. The aim of this study is to provide knowledge on the use of TLS and UAV-DP data and GPS-acquired points within the transmission-based muography process and how these data could improve or worsen the muon imaging results. Moreover, this study confirmed that muography applications require a multidisciplinary approach.

Use of Advanced Technologies for Topographic Surveys in Civil Construction

The complexity that has characterized market relations in recent years, with demands for product and process innovation, has even had repercussions on more traditional activities, such as the civil construction segment. Behind only agriculture, the construction industry represents 13% of the global GDP and its volume is US$ 8 trillion per year. However, construction projects often exceed budget by 80%, and deadlines by 20 months. Between 8% and 10% of productivity gains are related to the insertion of technologies (IPEA, 2022). In the field of civil construction, these digital technologies, such as cloud computing, automation, virtual reality and augmented reality, 3D modeling, communication applications and BIM—Building Information Modeling and even machine learning, have been called Construction 4.0. This article evaluates the feasibility of replacing the use of Terrestrial Laser Scanner (TLS) by the use of Unmanned Aerial Vehicles (UAV). For this, it presents a comparison in the use of equipment for carrying out planimetric surveys in civil construction, using as an example the UAV and the TLS—more modern equipment, in addition to the total station—more conventional equipment—for surveying control points. The results show that in the UAV image processing, the RMSE presented a centimeter accuracy (1.93044 cm) for the model. Even if the accuracy of the models generated by TLS is millimetric, it can be considered that the results obtained here were satisfactory, however it is necessary to apply imaging techniques more efficiently to obtain a more accurate product, in order to arrive at millimeter accuracy. Studies on better positioning of targets and georeferencing of models would also be of great contribution to applications in civil construction.

A New Approach for Structural Monitoring Based on Terrestrial Laser Scan Data Using Control Planes

Laser scanning is a survey method that enables the obtaining of several data points on surfaces through the observation of horizontal and vertical angles and electronic distance measurements. The result of these observations is a set of 3D points named point clouds, which can be obtained from scans using total stations or the Terrestrial Laser Scanner (TLS). Currently, the use of TLS in geodetic structural deformation monitoring activities is under evaluation, since this technique can provide a greater number of points in a shorter period, when compared to scans performed by total stations. In this research, the feasibility of using control planes for geodetic monitoring was investigated in a controlled laboratory environment, exploring the current trend of parameterization of point clouds. From the development of an Experimental Plane Control (EPC) containing a flat surface that could be inclined in a controlled way, simultaneous scans with TLS and total station were carried out at different inclinations of the control plane. Both surveys were done in frontal scan mode (minimum plane inclination of 0º53’ and maximum plane inclination of 3º28’) and in oblique mode (plane inclination of 1º09’), where the plane inclination angles were generated by the rotation in EPC base, considering the first plane position as reference to inclination calculating. From parametrization of point clouds, a new approach was developed to test the significance of the estimated inclination angle of the plane in relation to a reference position. The results showed that it is possible to confirm that the inclined angles were statistically significant, but that the TLS scanning position can interfere in the determination of these data for monitoring purposes.

Proposal of an integrated 3D architectural survey method for application in historic agri-food building analysis and representation

In Italy, historic agri-food buildings can be considered a relevant material expression and testimony of century-old agriculture and food processing practices handed down by generations. Recently they have gained ever-growing importance as a part of the wider architectural heritage. As such, they deserve dedicated general surveys to build a thorough knowledge of their distinctive characteristics and investigate their current condition, setting the basis for the implementation of planning and management actions for their sustainable valorisation. To this end, building information modelling can be considered an efficient strategy to preserve construction information by creating 3D models based on surveys of the built heritage. To acquire in a fast and accurate way geometric, reflectance, and colour data of rural buildings as a 3D point cloud, the terrestrial laser scanner (TLS) represents a powerful tool. The traditional TLS-based survey methods, in the context of historic agricultural buildings, have several limitations, mainly due to the presence of inaccessible parts and bulky machinery once used for processing and storage. In the present research, to overcome these issues and thus have a complete survey, we describe a proposal of an integrated methodology for obtaining 3D point-cloud data of existing rural agri-food buildings based on the integrated use of TLS, hand-held scanner, and unmanned aerial vehicles instruments. The proposed methodology was tested in surveying three historic agri-food buildings, and the accuracy of the obtained 3D point cloud was calculated using the root mean square error (RMSE) on the X, Y, and Z alignment of the two different 3D point clouds in correspondence of the used B/W target. Moreover, a measure of the distance between two merged 3D point clouds in their overlap area has been performed using the multi-scale model to model cloud comparison (M3C2). RMSE analysis always shows values lesser than 1 cm, and M3C2 shows values between 0 and about 6 cm.

The Combined Use of Terrestrial Laser Scanner and Handheld 3D Scanner for 3D Modeling of Piping Instrumentation at Oil and Gas Company

Three-dimensional (3D) models are indispensable in managing, operating, maintaining, and repairing piping instrumentation activities in oil and gas companies. 3D models are expected to provide more interactive and representative information according to actual objects. Several technologies that can be used to generate piping instrumentation 3D maps are Terrestrial Laser Scanner (TLS) and Handheld 3D Scanner (HS). This study aims to create a 3D model of piping instrumentation using a combination of TLS and HS and analyze the results of data validation used for modeling. The results showed that a 3D modeling of piping instrumentation could be generated accurately using a combination of TLS and HS technologies. Merging between the two data is carried out through a cloud-to-cloud registration process based on the geometry of the object by considering the selection of reference data, the similarity of the scale factor, the unit of measure, and the overlap of the two data. The registration error generated in combining these two methods is less than 0.003 m. The resulting model still has drawbacks, which is the absence of coding for the pipe caused by the unavailability of the Piping and Instrumentation Diagram (P&ID) during modeling. The geometric validation of the model size value using reference data and the field size has the largest absolute difference of 0.0034 m with an average absolute deviation of 0.0016 m.

A method for full three-dimensional kinematic analysis of steep rock walls based on high-resolution point cloud data

The predisposition of a slope to generate rockfalls is related to the intensity of rock mass jointing and the geometric arrangement of discontinuities intersecting the rock face. With the increasing use of terrestrial laser scanner (TLS) in rock slope surveying, methods have been proposed to semi-automatically extract the spatial properties of outcropping discontinuities from high-resolution topographic data. The present paper builds upon one of such methods (named DiAna), and extends it to enhance the assessment of rockfall susceptibility over steep rock walls. In particular, a Matlab routine (named DiAna-K) that incorporates a full three-dimensional derivation of kinematic analysis principles is introduced. Kinematic tests for plane, wedge, block toppling, flexural toppling, and free fall failure are formulated by explicitly accounting for the presence of overhanging areas of the rock face as well as varying frictional strengths across different discontinuity sets, planes, or intersections between planes. Results from a test application at an abandoned quarry site highlight the ability of the proposed procedure to provide detailed insights into the kinematic feasibility of structurally controlled instabilities. They also demonstrate the importance of properly defining failure mechanisms over steep (and usually undersampled) topographies in order to derive realistic quantifications of rockfall hazards.

Weathering processes and rates of scarp retreat in a Mediterranean mountain environment: A multi-analytical approach from terrestrial laser scanning to microscale surveys

Estimating the rates of Earth surface processes may provide a deeper comprehension of landscape shaping at different spatial/temporal scales in the light of ongoing or future climate changes and geomorphological hazards. This study explores the use of terrestrial laser scanner combined with macro/micromorphological and compositional analyses to assess three-year surface and volume changes on three granodiorite scarps in a Mediterranean upland environment (Sila Massif, Italy), estimate erosion/accumulation rates and relate them to specific geomorphic processes, weathering patterns and grades. The three scarps, affected by intermediate to high weathering grade classes, respond differently according to aspect and grain size. On coarser-grained granite of the W-facing, scarp 1 rounded weathering patterns developed because of the moister, less insolated conditions. On the finer-grained rocks of the SE-facing scarp 2, with prolonged insolation and temporary moisture, angular patterns prevail. Fine vs. coarse weathered material detached from the scarps is facilitated by prevalent chemical or physical rock degradation processes. On scarp 3, the coexistence of zones affected by pronounced physical breakdown and others influenced by pervasive chemical weathering is due to intermediate microclimatic conditions brought about by varying E and NE-facing aspect of the scarp. Rock jointing likely controls rockfall processes. The average retreat/advance rates of the scarps range from n × 10−6 to 10−2 m yr−1, with net erosion rates in the range 1 × 10−2–3 × 10−4 m yr−1 and are consistent with literature data. 3D models also allow the assessment of pre-failure landslide processes affecting the scarps and their relationships with weathering.

TLS and GB-RAR Measurements of Vibration Frequencies and Oscillation Amplitudes of Tall Structures: An Application to Wind Towers

This article presents a methodology for the monitoring of tall structures based on the joint use of a terrestrial laser scanner (TLS), configured in line scanner mode, and a ground-based real aperture radar (GB-RAR) interferometer. The methodology provides both natural frequencies and oscillation amplitudes of tall structures. Acquisitions of the surface of the tall structure are performed by the TLS with a high sampling rate: each line scan provides an instantaneous longitudinal section. By interpolating the points of each line, oscillation profiles are estimated with a much better precision than each single point. The amplitude and frequency of the main oscillation mode of the whole structure are derived from the TLS profiles. GB-RAR measurements are used to measure the vibration frequencies of higher oscillation modes which are not caught by the TLS due its lower precision in the measurement of displacements. In contrast, the high spatial resolution of TLS measurements provides an accurate description of oscillation amplitude along the tower, which cannot be caught by the GB-RAR, due to its poorer spatial resolution. TLS and GB-RAR acquisitions are simultaneous. The comparison with the analytical solution for oscillation modes demonstrates that the proposed methodology can provide useful information for structural health monitoring (SHM). The methodology does not require the use of targets on the structure and it can be applied during its normal use, even in presence of dynamic loads (wind, traffic vibrations, etc.). A test was carried out on a wind tower where the synergistic use of TLS and GB-RAR made it possible to fully describe the spectral properties of the tower and at the same time measure the amplitude of the first oscillation mode along the tower with a high spatial resolution.

Assessment on topographic mapping using total station and terrestrial laser scanner technology (case study: Kiara Payung area, Sumedang)

The unique capability of Terrestrial Laser Scanner (TLS) technology in observing a considerable amount of any object above the Earth’s surface opens an interesting opportunity to produce fast and reliable topographic maps. However, the use of TLS for topographic mapping should be thoroughly investigated in many aspects, including the accuracy of the observed data, the field acquisition, human resource, data processing, cost, and time acquisition. The purpose of this research is to carry out preliminary investigations. The methodology of this research consists of a reconnaissance survey, measurement planning, TLS, Total station, and Global Positioning System (GPS) data acquisition, georeferenced, filtering, 3D (Dimension) modeling and map visualization. Several aspects of the result compared with the conventional techniques by using Electronic Total Station (ETS). The results of this research show that the average error of measurements is approximately 4 mm and the detail level of the generated Digital Elevation Model (DEM) is pretty good, as it is indicated by a huge number of total point clouds (223.460 points) with the point density of about 0.25 m on optimum scanning area. TLS is suitable for a fast mapping area with a considerably large scale (1:300). In addition, based on time and human resources for mapping in the same area, the topographic mapping by TLS requires lesser time and human resources than mapping by the other methods such as ETS. The only disadvantage of using TLS is its price is still costly. As a preliminary conclusion, the TLS is more suitable to be used on high accuracy mapping, such as the reconstruction of the building, cut and fill survey, documentation of historical building.

Integration of reverse engineering and non-linear numerical analysis for the seismic assessment of historical adobe buildings

Abstract This paper aims at presenting a methodology that integrates reverse engineering tools with a combination of advanced and simplified analytical methods to perform predictive analysis of the structural behavior of historical adobe buildings under seismic loads. This methodology proposes the joint use of terrestrial laser scanner and photogrammetry to obtain accurate geometrical models. The methodology also proposes the in-situ measurement of structural system properties through experimental modal tests. All the collected information is used to create representative Finite Element models which are then considered for performing predictive non-linear analyses and identifying the most probable collapse mechanisms. Limit analysis method is finally used to complement the analysis and to assess the structural performance of the adobe building under study considering different seismic scenarios. The methodology proposed in this paper is validated in the church of San Juan Bautista de Huaro, located in Cusco, Peru. This church was built in the 16th century and is known for its impressive mural paintings covering the entire indoor surface of the church. The results of the seismic assessment methodology proposed in this paper allowed to estimate the global behavior and possible damage patterns in the church during seismic events, showing that the most probable failure mechanisms would be the global rocking of the facade and the partial collapse of tympanum of the facade. The application of this methodology also allowed defining the performance levels of this church when facing different seismic scenarios. The results showed that the church should stay in a safe state until occasional earthquakes with a return period of 72 years. However, the results also indicate that rare earthquakes (return period of 475 years) will produce an unsafe structural condition with partial collapses of structural elements.

DIGITAL PHOTOGRAMMETRY AS A RESOURCE FOR CUBAN CULTURAL HERITAGE: EDUCATIONAL EXPERIENCES AND COMMUNITY ENGAGEMENT WITHIN THE INNOVA CUBA PROJECT

Abstract. The Laboratory of Geomatics for Environment and Conservation of Cultural Heritage (GECO – University of Florence) has been involved since 2011 in a process of technological transfer in collaboration with the Oficina del Historiador de La Ciudad de La Habana (OHcH). The know-how transfer concerning geomatics techniques for documentation and surveying of cultural heritage is of fundamental interest for the principal Institution designated to the protection of Havana historical centre. The first project (2011–2014) was mainly focused on the formation of specialized technicians from OHcH in the use of Terrestrial Laser Scanner (TLS), for documentation purposes of monumental and architectonical heritage. The ongoing project, INNOVA CUBA – “International and intersectoral intervention for the safeguard of the cultural heritage of the country” started in 2017, is funded by AICS – Italian Agency for Development Cooperation and coordinated by ARCS – Culture Solidali. The introduction of digital close-range photogrammetry represents the natural progression of this educational process, thus implementing the range of innovative surveying technologies available, in terms of instruments, software and technical know-how. The two-weeks training experience in Havana (2018) provided the participants, technical staff from OHcH and other institutions, all the necessary knowledge to be autonomously able to choose the suitable surveying technique, depending on object characteristics and on available devices, to correctly plan the survey and evaluate its metric quality. A final workshop, for a wider audience, was the opportunity to introduce future crowdsourcing photogrammetric activities, to improve the sensitivity and engagement of local community towards heritage protection and valorisation processes.

Use of terrestrial laser scanner for determination the volume of trees growing under canopy

Use of terrestrial laser scanner for determination the volume of trees growing under canopy

Use of terrestrial laser scanner for determination the volume of trees growing under canopy

Use of terrestrial laser scanner for determination the volume of trees growing under canopy

An automated approach for wood-leaf separation from terrestrial LIDAR point clouds using the density based clustering algorithm DBSCAN

The terrestrial light detection and ranging (LiDAR) technique has been recently used to provide 3D structural information of forest canopy at the individual tree level. However, the operational use of Terrestrial Laser Scanner (TLS) for canopy characterization of broadleaf non-deciduous forests needs further investigations. The estimation of wood volume, above-ground woody biomass, tree canopy characteristics and leaf area index often requires separation of photosynthetically active material and non-photosynthetically active material. This article describes an automated wood-leaves separation method, based on spatial geometric information of TLS point clouds, for broad leaved non-deciduous trees. Scans of seven individuals of Quercus suber L. trees were acquired by using the TLS phase-based Leica HDS6100. Point clouds were partitioned in cubic volumes (voxels) that were used as input to generate clusters through the point density algorithm DBSCAN. The clustering process led to the identification of wood and non-wood voxels. A specific automatic routine was written to process data from the point clouds to the visualization of clustering results. The analysis of results showed good performance for this approach, with the overall accuracy in classifying wood components of trees ranging from 95% to 97%. The largest accuracies were observed for branches larger than 5 cm in diameter whereas the accuracy of classification dropped, as expected, for branches with diameter lower than 3 cm.The results suggest that the proposed method can be conveniently used to extract woody components from point clouds of broad leaved non-deciduous trees.

Remote sensing of Carpathian flysch landslides with the use of terrestrial laser scanner

Terrestrial laser scanning helps us to detect unstable subsurface behaviour, assessing the slope stability and potential landslide failure modes. If the slopes are regularly observed, the risk of slope movement and subsequent consequences may be considerably reduced. This allows for optimum land use conditions that are economically justified. Landslides in the Carpathian flysch have a peculiar susceptibility to activation due to the region’s geological structure. This work addresses the problem of monitoring and analysing the effects of landslides associated with the operation of routes (roads and railway lines) running through the slopes of the Carpathian flysch. The terrestrial laser scanner enables site remote sensing in a simple and automated manner. Regular measurements with multiple scanner positions may be used for long term slope monitoring. A detailed geological structural model allows for risk assessment with regards to failure modes, and it allows for a slope stability assessment. The model, along with the substrate parameters, introduced into the Finite Element Analysis package enables an analysis of the effects of landslide susceptibility and the displacements of the terrain surface in time, as well as due to different loading cases.

Use of Terrestrial Laser Scanner for Rigid Airport Pavement Management.

The evaluation of the structural efficiency of airport infrastructures is a complex task. Faulting is one of the most important indicators of rigid pavement performance. The aim of our study is to provide a new method for faulting detection and computation on jointed concrete pavements. Nowadays, the assessment of faulting is performed with the use of laborious and time-consuming measurements that strongly hinder aircraft traffic. We proposed a field procedure for Terrestrial Laser Scanner data acquisition and a computation flow chart in order to identify and quantify the fault size at each joint of apron slabs. The total point cloud has been used to compute the least square plane fitting those points. The best-fit plane for each slab has been computed too. The attitude of each slab plane with respect to both the adjacent ones and the apron reference plane has been determined by the normal vectors to the surfaces. Faulting has been evaluated as the difference in elevation between the slab planes along chosen sections. For a more accurate evaluation of the faulting value, we have then considered a few strips of data covering rectangular areas of different sizes across the joints. The accuracy of the estimated quantities has been computed too.

MODELLING SINGLE TREE STRUCTURE WITH TERRESTRIAL LASER SCANNER

Abstract. Recent technological developments, which has reliable accuracy and quality for all engineering works, such as remote sensing tools have wide range use in forestry applications. Last decade, sustainable use and management opportunities of forest resources are favorite topics. Thus, precision of obtained data plays an important role in evaluation of current status of forests' value. The use of aerial and terrestrial laser technology has more reliable and effective models to advance the appropriate natural resource management. This study investigates the use of terrestrial laser scanner (TLS) technology in forestry, and also the methodological data processing stages for tree volume extraction is explained. Z+F Imager 5010C TLS system was used for measure single tree information such as tree height, diameter of breast height, branch volume and canopy closure. In this context more detailed and accurate data can be obtained than conventional inventory sampling in forestry by using TLS systems. However the accuracy of obtained data is up to the experiences of TLS operator in the field. Number of scan stations and its positions are other important factors to reduce noise effect and accurate 3D modelling. The results indicated that the use of point cloud data to extract tree information for forestry applications are promising methodology for precision forestry.

Using an ultra-long-range terrestrial laser scanner to monitor the net mass balance of Urumqi Glacier No. 1, eastern Tien Shan, China, at the monthly scale

ABSTRACTWe describe the use of a terrestrial laser scanner (TLS) to monitor the net mass balance of Urumqi Glacier No. 1, eastern Tien Shan. We used an ultra-long-range Riegl VZ®-6000 TLS, which is specially designed for surveying snow- and ice-covered terrain, to create repeated high spatiotemporal resolution DEMs, focusing on the monthly-scale (25 April–28 May 2015) net mass balance. According to the TLS-derived DEMs, the area of Urumqi Glacier No. 1 was 1.558 km2on 25 April 2015 and the average surface elevation change was 0.225 m. By comparing the results from the use of TLS with the conventional glaciological mass-balance method, the correlation coefficient (R2) between glaciological elevation changes of individual stakes and the TLS-derived geodetic elevation change of corresponding points was 0.85. Considering the uncertainty of both methods, this is a promising result. Using the in situ measured snow densities (snow pits) of the glacier surface, the geodetic net mass balance was 0.074 m w.e., which is slightly positive. The mean uncertainty in the TLS-derived monthly net mass balance was 0.018 m w.e., showing that the TLS surveying system presented accurate and relevant results and is therefore suitable to monitor mass-balance evolution of mountain glaciers.

3D TEXTURED MODELLING OF BOTH EXTERIOR AND INTERIOR OF KOREAN STYLED ARCHITECTURES

Abstract. This paper describes 3D modelling procedure of two Korean styled architectures which were performed through a series of processing from data acquired with the terrestrial laser scanner. These two case projects illustate the use of terrestrial laser scanner as a digital documentation tool for management, conservation and restoration of the cultural assets. We showed an approach to automate reconstruction of both the outside and inside models of a building from laser scanning data. Laser scanning technology is much more efficient than existing photogrammetry in measuring shape and constructing spatial database for preservation and restoration of cultural assets as well as for deformation monitoring and safety diagnosis of structures.

FIRST EXPERIENCES WITH THE TRIMBLE SX10 SCANNING TOTAL STATION FOR BUILDING FACADE SURVEY

Abstract. The use of Terrestrial Laser Scanner (TLS) tends to become a solution in many research areas related to large scale surveying. Meanwhile, the technological advances combined with the investigation of user needs have brought to the design of innovative devices known as scanning total stations. Such instruments merge in a unique hardware both scanning and surveying facilities. Even if their scanning rate is often reduced compared to conventional TLS, they make it possible to directly georeference laser scanning projects and to complete them with measurements of individual points of interest. The recent Trimble SX10 which was launched on the market in early October 2016 has been tested and some experiences carried out with it are reported in this paper. The analyses mainly focus on the survey of a building facade. Next to laser scanning survey, a photogrammetry campaign using an Unmanned Aerial Vehicle (UAV) has been carried out. These different datasets are used to assess the Trimble SX10 issued point clouds through a set of comparisons. Since georeferencing is possible either directly or indirectly using this device, data processed both ways are also compared to conclude about the more reliable method.