scholarly journals INTEGRATION OF ACTIVE SENSORS FOR GEOMETRIC ANALYSIS OF THE CHAPEL OF THE HOLY SHROUD

2019 ◽  
Vol XLII-2/W15 ◽  
pp. 149-156 ◽  
Author(s):  
S. Barba ◽  
A. di Filippo ◽  
M. Limongiello ◽  
B. Messina
Keyword(s):  
Laser System ◽  
Geometric Analysis ◽  
Laser Scanner ◽  
3D Models ◽  
Active Sensors ◽  
Survey Techniques ◽  
Accuracy And Precision ◽  
Complex Process

<p><strong>Abstract.</strong> The digital acquisition of Cultural Heritage is a complex process, highly depending on the nature of the object as well as the purpose of its detection. Even if there are different survey techniques and sensors that allow the generation of realistic 3D models, defined by a good metric quality and a detail consistent with the geometric characteristics of the object, an interesting goal could be to develop a unified treatment of the methodologies. The Chapel of the Holy Shroud, with its intricate articulation, becomes the benchmark to test an integrated protocol between a terrestrial laser scanner (TLS) and a wearable mobile laser system (WMLS) based on a SLAM approach. In order to quantify the accuracy and precision of the latter solution, several forms of comparison are proposed. For the case study the ZEB-REVO, produced and marketed by GeoSLAM, is tested. Computations of cloud-to-cloud (C2C) absolute distances, comparisons of slices and extractions of planar features are performed, using stationary laser scanner (Faro Focus<sup>S</sup> S350) as a reference. Finally, the obtained results are reported, allowing us to assert that the quality of the WMLS measurements is compatible with the data provided by the manufacturer, thus making the instrumentation suitable for certain specific applications.</p>

scholarly journals Digital surveying and 3D modelling structural shape pipelines for instability monitoring in historical buildings: a strategy of versatile mesh models for ruined and endangered heritage

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 84
Author(s):  
Raffaella De Marco ◽  
Sandro Parrinello
Keyword(s):  
Laser Scanner ◽  
Structural Behaviour ◽  
Structural Shape ◽  
Built Heritage ◽  
Levels Of Detail ◽  
Aerial Vehicle ◽  
The Church ◽  
Mesh Models

Cultural heritage and the attendant variety of built heritage demands a scientific approach from European committees: one related to the difficulties in its protection and management. This is primarily due to the lack of emergency protocols related to the structural knowledge and documentation pertaining to architecture and its ruins, specifically in terms of the goals of protection and intervention for endangered heritage affected by mechanical instabilities. Here, we focus on a rapid and reliable structural documentation pipeline for application to historical built heritage, and we introduce a case study of the Church of the Annunciation in Pokcha, Russia, while we also review the incorporation of integrated 3D survey products into reality-based models. This practice increases the possibility of systematising data through methodological phases and controlling the quality of numerical components into 3D polygonal meshes, with millimetric levels of detail and triangulation through the integration of terrestrial laser scanner and unmanned aerial vehicle survey data. These models are aimed at emphasising morphological qualities related to structural behaviour, thus highlighting areas of deformation and instability of the architectural system for analysis via computational platforms in view of obtaining information related to tensional behaviour and emergency risks.

scholarly journals 3D MODELS OF OBJECTS IN PROCESS OF RECONSTRUCTION

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Jovana Radović
Keyword(s):  
Laser Scanning ◽  
Laser System ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Terrestrial Laser Scanning ◽  
3D Models ◽  
Terrestrial Laser Scanner ◽  
Accurate Data ◽  
Final Model ◽  
Airborne Laser

Within the last years terrestrial and airborne laser scanning has become a powerful technique for fast and efficient three-dimensional data acquisition of different kinds of objects. Airborne laser system (LiDAR) collects accurate georeferenced data of extremely large areas very quickly while the terrestrial laser scanner produces dense and geometrically accurate data. The combination of these two segments of laser scanning provides different areas of application. One of the applications is in the process of reconstruction of objects. Objects recorded with laser scanning technology and transferred into the final model represent the basis for building an object as it was original. In this paper, there will be shown two case studies based on usage of airborne and terrestrial laser scanning and processing of the data collected by them.

scholarly journals Use of a Wearable Mobile Laser System in Seamless Indoor 3D Mapping of a Complex Historical Site

2018 ◽  
Vol 10 (12) ◽  
pp. 1897 ◽  
Author(s):  
Andrea di Filippo ◽  
Luis Sánchez-Aparicio ◽  
Salvatore Barba ◽  
José Martín-Jiménez ◽  
Rocío Mora ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser System ◽  
Laser Scanner ◽  
Terrestrial Laser Scanning ◽  
3D Models ◽  
3D Mapping ◽  
Interior Space ◽  
Structural Problems ◽  
Heritage Building ◽  
Terrestrial Photogrammetry

This paper presents an efficient solution, based on a wearable mobile laser system (WMLS), for the digitalization and modelling of a complex cultural heritage building. A procedural pipeline is formalized for the data acquisition, processing and generation of cartographic products over a XV century palace located in Segovia, Spain. The complexity, represented by an intricate interior space and by the presence of important structural problems, prevents the use of standard protocols such as those based on terrestrial photogrammetry or terrestrial laser scanning, making the WMLS the most suitable and powerful solution for the design of restoration actions. The results obtained corroborate with the robustness and accuracy of the digitalization strategy, allowing for the generation of 3D models and 2D cartographic products with the required level of quality and time needed to digitalize the area by a terrestrial laser scanner.

Conversion of a Telecommunications Antenna into a Radio Telescope: Laser Scanner Measurements of Optics and Dish Surface Quality of a Cassegrain Antenna

2019 ◽  
Vol 08 (03) ◽  
pp. 1950010
Author(s):  
Asif Rasha ◽  
Tim Natusch ◽  
Christophe Granet ◽  
Sergei Gulyaev
Keyword(s):  
Surface Quality ◽  
Radio Telescope ◽  
Surface Deformation ◽  
Elevation Angle ◽  
Laser Scanner ◽  
Length Variation ◽  
Cassegrain Antenna ◽  
Telescope Optics

A number of countries have identified redundant large telecommunications antennas (TA) and indicated their intention to convert them into radio telescopes (RT). As the efficiency of a parabolic dish radio telescope depends on its surface quality and optical alignment, a careful assessment of these properties should be undertaken before conversion. Here, as a case study, we describe a laser scanning (LS) procedure we developed and used for the Warkworth 30[Formula: see text]m Cassegrain antenna. To investigate gravity-induced mechanical deformation of the antenna surfaces and structure, we conducted measurements at elevation angles ranging from 6 to 90 degrees. The ability of a laser scanner to survey its nominal [Formula: see text] steradian surroundings allows for simultaneous study of the main and subreflectors, readily permitting a dynamic investigation of variation of the telescope optics as elevation changes occur. In particular, the method we present here allows determination of the surface quality of both main and subreflectors, the displacement between centers of the reflectors, their relative rotations and focal length variation as a function of elevation angle. We discuss details of settings, measurements, data processing and analysis focusing on possible difficulties and pitfalls. In our case study, no significant elevation-dependent surface deformation of the reflectors was observed, with the overall standard deviation of the postfit residuals varying between 1.0 and 1.7[Formula: see text]mm as elevation angle changes from 90∘ to 6∘, respectively. We, therefore, conclude that in our case both the main reflector and the subreflector, as well as the telescope optics, remain unaffected by gravitational deformation within the accuracy of the measurements, a conclusion that can possibly be extended to the similar class of TA currently considered for conversion.

Geometric Analysis of Pipeline Elbows Through Reverse Engineering and Their Associated Imperfections

2014 ◽  
Author(s):  
Muntaseer Kainat ◽  
Celal Cakiroglu ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Michael Martens
Keyword(s):  
Reverse Engineering ◽  
Wall Thickness ◽  
Geometric Analysis ◽  
Laser Scanner ◽  
Initial Imperfection ◽  
3D Models ◽  
Element Analysis ◽  
Engineering Software ◽  
Pipe Elbow ◽  
The Ideal

Pipe elbow is a common feature in pipelines and piping systems as a means to changing directions of otherwise straight pipelines. Irrespective of the processes involved in manufacturing pipe elbows, it is of interest to investigate whether they have any geometric imperfections. Researchers at the University of Alberta have devised a technique to measure initial imperfection of straight pipes prior to testing, using high resolution 3D surface profiler in conjunction with 3D reverse engineering software. The objective of the current study is to extend the imperfections measurement technique from measuring straight pipe segments to pipe elbows. Six (6) ninety (90) degree elbows are measured in this research with outside diameters ranging from NPS 12 inch to NPS 42 inch. A 3D laser scanner is used to acquire surface data and create 3D models corresponding to each elbow. A method for the geometric analysis of the elbows is developed using 3D inspection and reverse engineering software Geomagic®. The geometric idealization of a pipe elbow is a torus, which can be defined by a circle revolving around an axis, coplanar with the circle. The idealized geometry for each elbow is obtained through the developed method of geometric analysis, which includes the diameter of the circle defining the torus, and its distance from the axis of revolution. The difference between the ideal torus and the scanned geometry is considered as imperfection of each pipe elbow. The wall thickness values at the ends or edges of select pipe elbows are also measured from the scanned data and are reported as percentage deviation from the specified wall thickness around the perimeter at different cross sections. The 3D reverse engineering of the elbows indicated that they resemble the ideal geometry very closely. The ovalization imperfections are seen to be well within the value specified by CSA Z662-11. The wall thickness deviations are seen to vary between −10% to +25% of the specified value, with increased thickness being more prominent in the elbows. Finite element analysis of an elbow with thickness imperfection shows that higher hoop stress appears on the intrados than initially intended.

scholarly journals Comparison of Two Approaches to GNSS Positioning Using Code Pseudoranges Generated by Smartphone Device

2021 ◽  
Vol 11 (11) ◽  
pp. 4787
Author(s):  
Massimiliano Pepe ◽  
Domenica Costantino ◽  
Gabriele Vozza ◽  
Vincenzo Saverio Alfio
Keyword(s):  
Mobile Devices ◽  
Single Point ◽  
Satellite System ◽  
Navigation Satellite ◽  
Gnss Positioning ◽  
Gis Applications ◽  
Accuracy And Precision ◽  
Global Navigation Satellite

The release of Android 7.0 has made raw GNSS positioning data available on smartphones and, as a result, this has allowed many experiments to be developed to evaluate the quality of GNSS positioning using mobile devices. This paper investigates the best positioning, using pseudorange measurement in the Differential Global Navigation Satellite System (DGNSS) and Single Point Positioning (SPP), obtained by smartphones. The experimental results show that SPP can be comparable to the DGNSS solution and can generally achieve an accuracy of one meter in planimetric positioning; in some conditions, an accuracy of less than one meter was achieved in the Easting coordinate. As far as altimetric positioning is concerned, it has been demonstrated that DGNSS is largely preferable to SPP. The aim of the research is to introduce a statistical method to evaluate the accuracy and precision of smartphone positioning that can be applied to any device since it is based only on the pseudoranges of the code. In order to improve the accuracy of positioning from mobile devices, two methods (Tukey and K-means) were used and applied, as they can detect and eliminate outliers in the data. Finally, the paper shows a case study on how the implementation of SPP on GIS applications for smartphones could improve citizen science experiments.

scholarly journals TESTING DIFFERENT SURVEY TECHNIQUES TO MODEL ARCHITECTONIC NARROW SPACES

2017 ◽  
Vol XLII-2/W5 ◽  
pp. 505-511 ◽  
Author(s):  
A. Mandelli ◽  
F. Fassi ◽  
L. Perfetti ◽  
C. Polari
Keyword(s):  
Laser Scanner ◽  
Technical Specification ◽  
Vast Number ◽  
Survey Techniques ◽  
Level Of Automation ◽  
Service Areas ◽  
Technical Specifications ◽  
Architectural Survey ◽  
Complex Scenario

In the architectural survey field, there has been the spread of a vast number of automated techniques. However, it is important to underline the gap that exists between the technical specification sheet of a particular instrument and its usability, accuracy and level of automation reachable in real cases scenario, especially speaking about Cultural Heritage (CH) field.<br><br> In fact, even if the technical specifications (range, accuracy and field of view) are known for each instrument, their functioning and features are influenced by the environment, shape and materials of the object. The results depend more on how techniques are employed than the nominal specifications of the instruments. The aim of this article is to evaluate the real usability, for the 1:50 architectonic restitution scale, of common and not so common survey techniques applied to the complex scenario of dark, intricate and narrow spaces such as service areas, corridors and stairs of Milan’s cathedral indoors. Tests have shown that the quality of the results is strongly affected by side-issues like the impossibility of following the theoretical ideal methodology when survey such spaces. The tested instruments are: the laser scanner Leica C10, the GeoSLAM ZEB1, the DOT DPI 8 and two photogrammetric setups, a full frame camera with a fisheye lens and the NCTech iSTAR, a panoramic camera. Each instrument presents advantages and limits concerning both the sensors themselves and the acquisition phase.

scholarly journals MODELING THE DECAY IN AN HBIM STARTING FROM 3D POINT CLOUDS. A FOLLOWED APPROACH FOR CULTURAL HERITAGE KNOWLEDGE

2017 ◽  
Vol XLII-2/W5 ◽  
pp. 605-612 ◽  
Author(s):  
F. Chiabrando ◽  
M. Lo Turco ◽  
F. Rinaudo
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
3D Models ◽  
Historical Building ◽  
North West ◽  
Survey Techniques ◽  
The North ◽  
3D Point Clouds ◽  
Subsequent Conversion ◽  
3D Information

The recent trends in architectural data management imply the scientific and professional collaborations of several disciplines involved in the design, restoration and maintenance. It seems an achieved concept that, in the next future, all the information connected to new interventions or conservation activities on historical buildings will be managed by using a BIM platform. Nowadays the actual range or image based metric survey techniques (mainly produced by using Terrestrial Laser Scanner or photogrammetric platform today more based on projective geometry) allow to generate 3D point clouds, 3D models, orthophotos and other outputs with assessed accuracy. The subsequent conversion of 3D information into parametric components, especially in an historical environment, is not easy and has a lot of open issues. According to the actual BIM commercial software and to the embedded tools or plugin, the paper deals with the methodology followed for the realization of two parametric 3D models (Palazzo Sarmatoris and Smistamento RoundHouse, two historical building in the north-west part of Italy). The paper describes the proposed workflow according to the employed plug-in for automatic reconstruction and to the solution adopted for the well-known problems connected to the modeling phase such as the vaults realization or the 3D irregular surfaces modeling. Finally, the studied strategy for mapping the decay in a BIM environment and the connected results with the conclusions and future perspectives are critically discussed.

scholarly journals HISTORICAL PHOTOGRAMMETRY AND TERRESTRIAL LASER SCANNING FOR THE 3D VIRTUAL RECONSTRUCTION OF DESTROYED STRUCTURES: A CASE STUDY IN ITALY

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 113-119 ◽  
Author(s):  
G. Bitelli ◽  
M. Dellapasqua ◽  
V. A. Girelli ◽  
S. Sbaraglia ◽  
M. A. Tinia
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Poor Quality ◽  
Armed Conflicts ◽  
Archaeological Sites ◽  
Geometric Information ◽  
Virtual Reconstruction ◽  
The City

The current dramatic episodes of destruction of archaeological sites have again highlighted the problem of the safeguarding the threatened heritage and, if possible, recovering those damaged by all the armed conflicts of the past.<br><br> The historical photogrammetry offers the possibility to recover a posteriori the geometrical and material properties of destroyed structures, reconstructing their 3D model to document, study and maintain their memory, until to support their real anastylosis.<br><br> The presented work is about the 3D reconstruction of the civic tower of the little town of Sant’Alberto, near the city of Ravenna, Italy. The tower, as a symbol of resistance and pride of the town's population, was destroyed in December 1944 by German troops in retaliation, when they were forced to leave the area.<br><br> A city committee has subsequently collected all the historical evidence concerning the tower, including a series of photographic images that can be used for the photogrammetric reconstruction; the images calibration and orientation have been solved using the geometric information derived by a terrestrial laser scanner survey realized in the area where the tower was originally located.<br><br> Despite the scarcity and very poor quality of the available images, the conducted photogrammetric procedure has allowed a complete and qualitatively satisfying object reconstruction, also thanks to the use of geometric constraint tools offered by the chosen software.<br><br> The integration between the obtained model of the old tower and the 3D TLS survey of the square made it possible to reconstruct the ancient situation of the area.

scholarly journals Amphitheater of Volterra: Case Study for the Representation of Excavation Data

2017 ◽  
Vol 1 (2) ◽  
pp. 269-281
Author(s):  
Carlo Battini ◽  
Elena Sorge
Keyword(s):  
Structure From Motion ◽  
Mobile Application ◽  
Three Dimensional ◽  
Laser Scanner ◽  
3D Models ◽  
Post Processing ◽  
The Subject ◽  
Three Dimensional Models ◽  
Digital Projection

The work presented wants to show how different techniques of expeditious relief can be combined together in order to better describe the subject studied. Techniques of digital projection as laser scanner, topography and Structure from Motion can be used simultaneously and interact with each other to create a rich database of colorimetric and metrics information. Methodologies that, at the same time, present the peculiarities and errors of peculiar relief of the technology employed.The case study examined in this type of research is the discovery of the amphitheater of Volterra. Discovered in July 2015 during the phases of reclamation of a stream, is located close to Porta Diana and a few hundred meters from the Roman Theater discovered in the last century. An excavation campaign undertaken Between October and November 2015 has allowed us to bring to light the crests of the supporting walls of the structure, revealing the presence of the three orders and a depth of about ten meters.The step of post processing has finally seen the use of three-dimensional models acquired both for the creation of images metrics necessary to the study of the stratigraphic units, both for studying a mobile application, 3D models and data of the excavation, easy to use for transmitting the information collected.  

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