Assessing Terrestrial Laser Scanning in Complex Environments

2014 ◽  
Vol 2 (2) ◽  
pp. 123-137 ◽  
Author(s):  
Jennifer Weber ◽  
Terry G. Powis
Keyword(s):  
Laser Scanning ◽  
Visual Analysis ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Current Data ◽  
Airborne Lidar ◽  
Archaeological Sites ◽  
Complex Environments ◽  
Non Invasive ◽  
Maya Site

AbstractThe majority of terrestrial scanning projects in archaeology have focused on heritage documentation, preservation, and the three-dimensional (3D) reconstruction of prominent sites and objects. While these are very important archaeological foci, not many have used terrestrial scanning methods for prospection and feature analysis, similar to the way many have employed airborne LiDAR. While airborne LiDAR scanning is able to situate and analyze archaeological sites on an expansive scale, the ground-based method also captures and defines any landscape anomalies or depressions from cultural features that have remained invisible to the naked eye due to environmental restrictions. In an attempt to test this recording method, we set out to paint a non-invasive, 3D digitized picture of the ancient Maya site of Pacbitun, Belize, using terrestrial scanning to distinctly detail Pacbitun’s structures, plazas, causeways, and karst features. This paper details the process through which 3D terrestrial scanning was executed at Pacbitun and three associated peripheral caves during the 2012 and 2013 field seasons. We discuss the potential laser scanning has for visual analysis in archaeology and evaluate application difficulties encountered in the field, as well as current data interpretation issues.

Urban energetics applications and Geomatic technologies in a Smart City perspective

2015 ◽  
Vol 6 (1) ◽  
pp. 19-29 ◽  
Author(s):  
G. Bitelli ◽  
P. Conte ◽  
T. Csoknyai ◽  
E. Mandanici
Keyword(s):  
Smart City ◽  
Laser Scanning ◽  
Near Infrared ◽  
Three Dimensional ◽  
Energy Sector ◽  
Primary Objective ◽  
Airborne Lidar ◽  
City Management ◽  
Urban Context ◽  
Research Areas

The management of an urban context in a Smart City perspective requires the development of innovative projects, with new applications in multidisciplinary research areas. They can be related to many aspects of city life and urban management: fuel consumption monitoring, energy efficiency issues, environment, social organization, traffic, urban transformations, etc. Geomatics, the modern discipline of gathering, storing, processing, and delivering digital spatially referenced information, can play a fundamental role in many of these areas, providing new efficient and productive methods for a precise mapping of different phenomena by traditional cartographic representation or by new methods of data visualization and manipulation (e.g. three-dimensional modelling, data fusion, etc.). The technologies involved are based on airborne or satellite remote sensing (in visible, near infrared, thermal bands), laser scanning, digital photogrammetry, satellite positioning and, first of all, appropriate sensor integration (online or offline). The aim of this work is to present and analyse some new opportunities offered by Geomatics technologies for a Smart City management, with a specific interest towards the energy sector related to buildings. Reducing consumption and CO2 emissions is a primary objective to be pursued for a sustainable development and, in this direction, an accurate knowledge of energy consumptions and waste for heating of single houses, blocks or districts is needed. A synoptic information regarding a city or a portion of a city can be acquired through sensors on board of airplanes or satellite platforms, operating in the thermal band. A problem to be investigated at the scale A problem to be investigated at the scale of the whole urban context is the Urban Heat Island (UHI), a phenomenon known and studied in the last decades. UHI is related not only to sensible heat released by anthropic activities, but also to land use variations and evapotranspiration reduction. The availability of thermal satellite sensors is fundamental to carry out multi-temporal studies in order to evaluate the dynamic behaviour of the UHI for a city. Working with a greater detail, districts or single buildings can be analysed by specifically designed airborne surveys. The activity has been recently carried out in the EnergyCity project, developed in the framework of the Central Europe programme established by UE. As demonstrated by the project, such data can be successfully integrated in a GIS storing all relevant data about buildings and energy supply, in order to create a powerful geospatial database for a Decision Support System assisting to reduce energy losses and CO2 emissions. Today, aerial thermal mapping could be furthermore integrated by terrestrial 3D surveys realized with Mobile Mapping Systems through multisensor platforms comprising thermal camera/s, laser scanning, GPS, inertial systems, etc. In this way the product can be a true 3D thermal model with good geometric properties, enlarging the possibilities in respect to conventional qualitative 2D images with simple colour palettes. Finally, some applications in the energy sector could benefit from the availability of a true 3D City Model, where the buildings are carefully described through three-dimensional elements. The processing of airborne LiDAR datasets for automated and semi-automated extraction of 3D buildings can provide such new generation of 3D city models.

scholarly journals Geomorphometric analysis of cave ceiling channels mapped with 3D terrestrial laser scanning

2016 ◽  
Author(s):  
Michal Gallay ◽  
Zdenko Hochmuth ◽  
Ján Kaňuk ◽  
Jaroslav Hofierka
Keyword(s):  
Laser Scanning ◽  
Methodological Approach ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Scalar Fields ◽  
Complex Environments ◽  
Digital Elevation ◽  
Unique Manner ◽  
Elevation Model ◽  
Different Levels

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organised vertically in different levels. Studying such complex environments traditionally requires tedious mapping, however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterisation and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional scalar fields which is sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a three-dimensional entity therefore a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3D computer graphics which can be applied to study other 3-D geomorphological forms

Development on Filtering Algorithms of Airborne LiDAR Point Clouds

2012 ◽  
Vol 226-228 ◽  
pp. 1892-1898
Author(s):  
Jian Qing Shi ◽  
Ting Chen Jiang ◽  
Ming Lian Jiao
Keyword(s):  
Remote Sensing ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Filtering Algorithms ◽  
Filtering Algorithm ◽  
Digital Elevation ◽  
City Model ◽  
Elevation Model

Airborne LiDAR is a new kind of surveying technology of remote sensing which developed rapidly during recent years. Raw laser scanning point clouds data include terrain points, building points, vegetation points, outlier points, etc.. In order to generate digital elevation model (DEM) and three-dimensional city model,these point clouds data must be filtered. Mathematical morphology based filtering algorithm, slope based filtering algorithm, TIN based filtering algorithm, moving surface based filtering algorithm, scanning lines based filtering algorithm and so on several representative filtering algorithms for LiDAR point clouds data have been introduced and discussed and contrasted in this paper. Based on these algorithms summarize the studying progresss about the filtering algorithm of airborne LiDAR point clouds data in home and abroad. In the end, the paper gives an expectation which will provides a reference for the following relative study.

scholarly journals HBIM, 3D drawing and virtual reality for archaeological sites and ancient ruins

2020 ◽  
Vol 11 (23) ◽  
pp. 16 ◽  
Author(s):  
Fabrizio Banfi
Keyword(s):  
Virtual Reality ◽  
Laser Scanning ◽  
New Technologies ◽  
Three Dimensional ◽  
Point Clouds ◽  
Archaeological Sites ◽  
Digital Information ◽  
Holistic Model ◽  
Digital Modelling ◽  
The Creation

<p class="VARAbstract">Data collection, documentation and analysis of the traces of ancient ruins and archaeological sites represent an inestimable value to be handed down to future generations. Thanks to the development of new technologies in the field of computer graphics, Building Information Modelling (BIM), Virtual Reality (VR) and three-dimensional (3D) digital survey, this research proposes new levels of interactivity between users and virtual environments capable of communicating the tangible and intangible values of remains of ancient ruins. In this particular field of development, 3D drawing and digital modelling are based on the application of new Scan-to-HBIM-to-VR specifications capable of transforming simple points (point clouds) into mathematical models and digital information. Thanks to the direct application of novel grades of generation (GOG) and accuracy (GOA) it has been possible to go beyond the creation of complex models for heritage BIM (HBIM) and explore the creation of informative 3D representation composed by sub-elements (granular HBIM objects) characterized by a further level of knowledge. The value of measurement, 3D drawing and digital modelling have been investigated from the scientific point of view and oriented to the generation of a holistic model able to relate both with architects, engineers, and surveyors but also with archaeologists, restorers and virtual tourists.</p><p>Highlights:</p><ul><li><p>The concept of ‘granular HBIM objects’ is introduced to show the unexpressed potential of the scan-to-BIM process for different types of data analyses and uses.</p></li><li><p>Sustainable development of VR projects for archaeological sites is proposed, allowing users to discover the hidden historical values with new levels of interactivity and information.</p></li><li><p>HBIM and VR projects have been improved through the integration of laser scanning, digital photogrammetry (terrestrial and UAV) and advanced modelling techniques.</p></li></ul>

scholarly journals Important Airborne Lidar Metrics of Canopy Structure for Estimating Snow Interception

2021 ◽  
Vol 13 (20) ◽  
pp. 4188
Author(s):  
Micah Russell ◽  
Jan U. H. Eitel ◽  
Timothy E. Link ◽  
Carlos A. Silva
Keyword(s):  
Laser Scanning ◽  
Mean Squared Error ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Variable Importance ◽  
Airborne Lidar ◽  
Extrinsic Factors ◽  
Area Index ◽  
Wide Range ◽  
Structural Metrics

Forest canopies exert significant controls over the spatial distribution of snow cover. Canopy snow interception efficiency is controlled by intrinsic processes (e.g., canopy structure), extrinsic processes (e.g., meteorological conditions), and the interaction of intrinsic-extrinsic factors (i.e., air temperature and branch stiffness). In hydrological models, intrinsic processes governing snow interception are typically represented by two-dimensional metrics like the leaf area index (LAI). To improve snow interception estimates and their scalability, new approaches are needed for better characterizing the three-dimensional distribution of canopy elements. Airborne laser scanning (ALS) provides a potential means of achieving this, with recent research focused on using ALS-derived metrics that describe forest spacing to predict interception storage. A wide range of canopy structural metrics that describe individual trees can also be extracted from ALS, although relatively little is known about which of them, and in what combination, best describes intrinsic canopy properties known to affect snow interception. The overarching goal of this study was to identify important ALS-derived canopy structural metrics that could help to further improve our ability to characterize intrinsic factors affecting snow interception. Specifically, we sought to determine how much variance in canopy intercepted snow volume can be explained by ALS-derived crown metrics, and what suite of existing and novel crown metrics most strongly affects canopy intercepted snow volume. To achieve this, we first used terrestrial laser scanning (TLS) to quantify snow interception on 14 trees. We then used these snow interception measurements to fit a random forest model with ALS-derived crown metrics as predictors. Next, we bootstrapped 1000 calculations of variable importance (percent increase in mean squared error when a given explanatory variable is removed), keeping nine canopy metrics for the final model that exceeded a variable importance threshold of 0.2. ALS-derived canopy metrics describing intrinsic tree structure explained approximately two-thirds of the snow interception variability (R2 ≥ 0.65, RMSE ≤ 0.52 m3, relative RMSE ≤ 48%) in our study when extrinsic factors were kept as constant as possible. For comparison, a generalized linear mixed-effects model predicting snow interception volume from LAI alone had a marginal R2 = 0.01. The three most important predictor variables were canopy length, whole-tree volume, and unobstructed returns (a novel metric). These results suggest that a suite of intrinsic variables may be used to map interception potential across larger areas and provide an improvement to interception estimates based on LAI.

scholarly journals APPLICABILITY ANALYSIS OF CLOTH SIMULATION FILTERING ALGORITHM FOR MOBILE LIDAR POINT CLOUD

2018 ◽  
Vol XLII-3 ◽  
pp. 107-111 ◽  
Author(s):  
S. Cai ◽  
W. Zhang ◽  
J. Qi ◽  
P. Wan ◽  
J. Shao ◽  
...  
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Cloth Simulation ◽  
Large Area ◽  
Three Samples ◽  
Separate Point ◽  
A New Technique

Classifying the original point clouds into ground and non-ground points is a key step in LiDAR (light detection and ranging) data post-processing. Cloth simulation filtering (CSF) algorithm, which based on a physical process, has been validated to be an accurate, automatic and easy-to-use algorithm for airborne LiDAR point cloud. As a new technique of three-dimensional data collection, the mobile laser scanning (MLS) has been gradually applied in various fields, such as reconstruction of digital terrain models (DTM), 3D building modeling and forest inventory and management. Compared with airborne LiDAR point cloud, there are some different features (such as point density feature, distribution feature and complexity feature) for mobile LiDAR point cloud. Some filtering algorithms for airborne LiDAR data were directly used in mobile LiDAR point cloud, but it did not give satisfactory results. In this paper, we explore the ability of the CSF algorithm for mobile LiDAR point cloud. Three samples with different shape of the terrain are selected to test the performance of this algorithm, which respectively yields total errors of 0.44&amp;thinsp;%, 0.77&amp;thinsp;% and1.20&amp;thinsp;%. Additionally, large area dataset is also tested to further validate the effectiveness of this algorithm, and results show that it can quickly and accurately separate point clouds into ground and non-ground points. In summary, this algorithm is efficient and reliable for mobile LiDAR point cloud.

scholarly journals INFOGRAPHIC MODELING BASED ON 3D LASER SURVEYING FOR INFORMED <i>UNIVERSAL DESIGN</i> IN ARCHAEOLOGICAL AREAS: THE CASE OF OPPIDUM OF THE ANCIENT CITY OF TUSCULUM

2017 ◽  
Vol IV-2/W2 ◽  
pp. 259-264
Author(s):  
L. Cemoli ◽  
S. D’Auria ◽  
F. De Silla ◽  
S. Pucci ◽  
R. M. Strollo
Keyword(s):  
Laser Scanning ◽  
Universal Design ◽  
Three Dimensional ◽  
Archaeological Sites ◽  
Landscape Value ◽  
Scientific Project ◽  
Three Dimensional Models ◽  
Archaeological Areas ◽  
Reduced Mobility ◽  
The Impact

The valorisation of archaeological sites represents a fundamental action for the social and economic development of a country. An archaeological park is often a territory characterized by significant testimonies of antiquity of great landscape value. For this reason, it should be configured as an authentic outdoor museum, enriched by natural, environmental, architectural and urban components. In order to fulfill these requirements, it is fundamental the elaboration of a coherent scientific project of preservation, fruition and valorisation of the area, which merge the different components necessary for the establishment of an archaeological museum-park.<br><br> One of the most critical aspects related to the fruition of archaeological sites is the accessibility to areas and routes, not always – if ever – designed for people with reduced mobility, also temporary (for example elderly, obese, visually impaired, etc.). In general, an established principle used in the new design is to pay attention to the so-called wide users, in accordance with the international guidelines summarized in the concept of Universal Design. In particular, this paper presents the use of three-dimensional models obtained from laser scanning surveys for the design of walking trails for people with reduced mobility in the Tusculum Archaeological-Cultural Park.<br><br> The work was based on the fundamental implementation of the three-dimensional survey with terrestrial laser scanning for the construction and the control of the complex morphology of the site, and on the subsequent integration of models of the intervention in the three-dimensional reality "as-built" of the site. The obtained infographic model allowed to study and simulate the impact of the routes for people with reduced mobility, and to verify its efficiency in the historical and landscape context. Moreover, it was possible to verify the construction of other facilities in the real conditions of the site.

scholarly journals Accuracy of Models Obtained from Digital Impressions Versus Scanning of Conventional Impressions

2021 ◽  
Author(s):  
Noha M. Elkersh ◽  
Rania A.Fahmy ◽  
Mohamed K. Zayet ◽  
Yousria S. Gaweesh
Keyword(s):  
Repeated Measures ◽  
Laser Scanning ◽  
Visual Analysis ◽  
Three Dimensional ◽  
Digital Model ◽  
Linear Measurements ◽  
Deviation Analysis ◽  
Digital Impressions ◽  
Mean Differences

Abstract Background Digital workflow has invaded the different dental specialities. It includes some steps, the first of them is the scan process and dental modelling. Many methods are available for digital model fabrication. Therefore, the aim of this in vivo study to assess and compare the accuracy of 3-dimensional (3D) digital dental models obtained from scanning of conventional impressions versus models from digital impressions. Materials and Methods Three-dimensional digital model files were obtained in vivo from three different methods including scanning of impressions by both Cone beam computed tomography (CBCT) machine (Veraview x800, JMorita) and desktop scanner (Smart optics, Vinyl Open Air). The same volunteers have received digital impressions by an intraoral scanner (CS3600). Six linear measurements were measured in each Stereolithography (STL) model and compared with direct calliper measurements. Additionally, STL files from the three systems were paired and superimposed using a best-fit algorithm in a 3D modelling software. Mean deviations between the STL shells were calculated by the software and color maps were obtained for visual analysis. Intra-class correlation coefficient (ICC) was calculated to determine the intra-examiner reliability. Paired t-test, ANOVA with repeated measures and Post Hoc test (Bonferroni adjusted) were used in the statistical analysis. Significance of the obtained results was judged at the 5% level. Results The linear measurements and 3D deviation analysis revealed significant differences in some measurements but were considered clinically accepted. Digital models obtained from laser scanning of the impressions revealed the least mean differences from the gold standard ranging from (-0.24 to 0.01 mm), while CBCT scanning of the impressions mean differences ranged from (0.16 to -0.04 mm). IOS revealed the highest mean differences ranging from (0.11 to 0.33 mm). Conclusion Scanning the impression with a desktop scanner provided the highest accuracy in full arch scans followed by scanning with CBCT but with decreased surface texture of the 3D mesh. While intraoral scanners showed the least accuracy for full arch scans up till now and need further improvement in their technology. All techniques can be applied in clinical practice providing the use of high quality machines.

scholarly journals THE SOIL SCIENCE & ARCHAEO-GEOPHYSICS ALLIANCE (SAGA): going beyond prospection

2018 ◽  
Vol 4 ◽  
Author(s):  
Carmen Cuenca-Garcia ◽  
Kayt Armstrong ◽  
Elina Aidona ◽  
Philippe De Smedt ◽  
Anne Rosveare ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Geophysical Methods ◽  
Cost Effective ◽  
Data Interpretation ◽  
Effective Field ◽  
Archaeological Sites ◽  
Non Invasive ◽  
Research Collaborations ◽  
Expected Benefits ◽  
The Relationship

Archaeological sites can be discovered and recorded in a high-resolution and non-invasive manner using geophysical methods. These measure the spatial variation of a range of physical properties of the soil which may be representative proxies of the subsurface archaeology. Less-invasive and cost-effective field procedures have become top-priority to mitigate the destructive effects on our cultural heritage from intensified land use, climate change and the current conflict panorama. At a time when many organisations are investing in advanced geophysical equipment, a major problem is that our ability to fully interpret the information available from geophysical datasets is still very limited. This deficiency prevents geophysical survey moving beyond basic prospection and becoming a significant tool for answering nuanced questions about archaeology and their host landscapes. This limitation arises from an incomplete understanding of the relationship between soil properties and geophysical measurements. Bridging this gap requires multi-disciplinary teams, testing novel methods, plus scholarly discussion to collate the outcomes of projects on this topic. Overcoming these challenges is a prerequisite for maximising the costeffectiveness of geophysical methods, realising the expected benefits of technological investment and allowing broader utility of geophysical methods in the cultural heritage sector. SAGA will build an international network of geophysicists, archaeologists, soil scientists and other experts to develop our capability to interpret geophysical data and promote research collaborations. Our vision is that after four years, SAGA will have created an environment within which emerging field procedures, enhanced data interpretation and a broader understanding of integrated geophysical methods can flourish.

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