Facility survey by handheld laser scanner using SLAM algorithm －A case study at THE MUSEUM MEIJI-MURA－

For a trustworthy least-squares (LS) solution, a good description of the stochastic properties of the measurements is indispensable. For a terrestrial laser scanner (TLS), the range variance can be described by a power law function with respect to the intensity of the reflected signal. The power and scaling factors depend on the laser scanner under consideration, and could be accurately determined by means of calibrations in 1d mode or residual analysis of LS adjustment. However, such procedures complicate significantly the use of empirical intensity models (IM). The extent to which a point-wise weighting is suitable when the derived variance covariance matrix (VCM) is further used in a LS adjustment remains moreover questionable. Thanks to closed loop simulations, where both the true geometry and stochastic model are under control, we investigate how variations of the parameters of the IM affect the results of a LS adjustment. As a case study, we consider the determination of the Cartesian coordinates of the control points (CP) from a B-splines curve. We show that a constant variance can be assessed to all the points of an object having homogeneous properties, without affecting the a posteriori variance factor or the loss of efficiency of the LS solution. The results from a real case scenario highlight that the conclusions of the simulations stay valid even for more challenging geometries. A procedure to determine the range variance is proposed to simplify the computation of the VCM.

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Modeling and Simulation of a Laser Scanner Sensor: An Industrial Application Case Study

Advances in Sustainable and Competitive Manufacturing Systems - Lecture Notes in Mechanical Engineering ◽

10.1007/978-3-319-00557-7_20 ◽

2013 ◽

pp. 245-258 ◽

Cited By ~ 2

Author(s):

Jose Lima ◽

José Gonçalves ◽

Paulo J. Costa ◽

A. Paulo Moreira

Keyword(s):

Modeling And Simulation ◽

Industrial Application ◽

Laser Scanner

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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 ◽

10.21014/acta_imeko.v10i1.895 ◽

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.

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Forest fuel assessment by LiDAR data. A case study in NE Italy

10.5194/egusphere-egu21-12755 ◽

2021 ◽

Author(s):

Flavio Taccaliti ◽

Lorenzo Venturini ◽

Niccolò Marchi ◽

Emanuele Lingua

Keyword(s):

Laser Scanner ◽

Remote Sensing Data ◽

Statistical Modelling ◽

Pinus Nigra ◽

Simulation Software ◽

Lidar Data ◽

Special Focus ◽

Forest Fuels ◽

Behaviour Simulation

Fuel management is a crucial action to maintain wildland fires under the threshold of manageability; hence, in order to allocate resources in the best way, wildland fuel mapping is regarded as a necessary tool by land managers. Several studies have used Aerial Laser Scanner (ALS) data to estimate forest fuels characteristics at plot level, but few have extended such estimates at a zonal level.In the context of the EU Interreg Project CROSSIT SAFER, a test of the possibilities of ALS data to predict fuels attributes has been performed in three different areas: an alpine basin, a coastal wildland-urban interface and a karstic highland. Eighteen sampling plots have been laid out over 6 forest categories, with a special focus on Pinus nigra J. F. Arnold artificial forests. Low density (average 4 points/m2) discrete return LiDAR data has been analysed with FUSION, a free point cloud analysis software tailored to forestry purposes; field and remote sensing data have been connected with simple statistical modelling and results have been spatialised over the case study areas to provide wall-to-wall inputs for FLAMMAP fire behaviour simulation software.Resulting maps can be of relevance for land managers to better highlight the most vulnerable or fire prone areas at a mesoscale administrative level. Limitations and room for improvement are pointed out, in the view that land management should keep updated with the latest technology available.

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3D Digital Documentation of a Cultural Heritage Site Using Terrestrial Laser Scanner—A Case Study

Lecture Notes in Civil Engineering - Applications of Geomatics in Civil Engineering ◽

10.1007/978-981-13-7067-0_3 ◽

2019 ◽

pp. 49-58 ◽

Cited By ~ 2

Author(s):

S. K. P. Kushwaha ◽

Karun Reuel Dayal ◽

Sachchidanand ◽

S. Raghavendra ◽

Hina Pande ◽

...

Keyword(s):

Cultural Heritage ◽

Laser Scanner ◽

Terrestrial Laser Scanner ◽

Heritage Site ◽

Digital Documentation

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

Journal of Astronomical Instrumentation ◽

10.1142/s2251171719500107 ◽

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.

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Further refinement of the Corbelling Theory for the equilibrium analysis of corbelled domes

Curved and Layered Structures ◽

10.1515/cls-2019-0003 ◽

2019 ◽

Vol 6 (1) ◽

pp. 30-40

Author(s):

Aguinaldo Fraddosio ◽

Nicola Lepore ◽

Mario Daniele Piccioni

Keyword(s):

Laser Scanner ◽

Equilibrium Analysis ◽

Structural Safety ◽

Structural Behavior ◽

Thick Shell ◽

Starting Point ◽

Further Development ◽

Load Conditions

Abstract The aim of this paper is to present a further development of the Corbelling Theory [1] for assessing the structural safety of “false domes” constructions like Trulli, and more generally for corbelled domes. In particular, it is well-known that a corbelled dome of a Trullo is a layered thick shell and that only the thin inner layer (candela) has a structural role. The proposed procedure extends the capabilities of the approach proposed in [2] to more general load conditions, including the infill. The effectiveness of the proposed approach is discussed through the analysis of a paradigmatic case study of a Trullo located in Alberobello. Since the geometry of the construction plays a fundamental role in the structural behavior, the starting point of the analysis was an accurate 3D-laser scanner survey of the dome. The obtained results give some interesting insights about the role of the infill load on the equilibrium of such kind of corbelled domes.

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XVIII Century Wooden Stretchers Structure Designed for Large Canvas and an Example of the Assessment Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.778.113 ◽

2013 ◽

Vol 778 ◽

pp. 113-118 ◽

Cited By ~ 1

Author(s):

Katarzyna Górecka ◽

Marek Sklodowski ◽

Piotr Pawłowski ◽

Joanna Szpor ◽

Henryk Arendarski

Keyword(s):

Laser Scanner ◽

Assessment Method ◽

Camera System ◽

Large Size ◽

Poor Access ◽

Unique Shape ◽

Actual Shape ◽

Frame Construction ◽

Direct Inspection

Paper discusses large size canvas paintings stretching methods and deformations and damages specific for large canvas resulting from an incorrect stretching. Analysis of the preservation state of a wooden stretcher construction and its functionality was an important step in development of the program of conservation work. The case study of M. H Loders painting "Adoration of the Magi" (XVIII c.) from the cathedral Saint - Aubain in Namur (Belgium) is presented. The painting is exhibited 5,5 m above the floor and has a unique shape, as the wooden stretcher frame is adjusted to the round apse walls. Thus usual direct inspection was difficult due to poor access to the reverse side of the painting. Preliminary conclusions on the construction and preservation state of the stretcher frame were drawn on the basis of a thorough inspection of the painting surface. Actual shape of the painting and precise stretchers dimensions were measured with a laser scanner. More information concerning the stretcher frame construction was obtained from a simple micro-camera system combined with LED lighting introduced from the canvas reverse side.

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