scholarly journals Geoinformatics Technologies for Preservation of Cultural Heritage, Case Study, Rákóczi-Bánffy Castle, Urmeniș, Bistriţa Năsăud County, Romania

2021 ◽  
Vol 11 (1) ◽  
pp. 41-48
Author(s):  
V.M. Rădulescu ◽  
G.M.T. Rădulescu ◽  
Sanda Naș ◽  
A.T. Rădulescu ◽  
M. Bondrea ◽  
...  

Abstract The paper presents an application of the methodology used in the paper “Synthetic analysis of geoinformatics technologies for cultural heritage conservation, methodological approach”. The creation of the 3D model of the Rákóczi-Bánffy Castle in Urmeniș, Bistrița Năsăud County, was done by applying and integrating Terrestrial Laser Scanning (TLS) technologies and aerial photogrammetry performed with an Unmanned Aerial Vehicle (UAV). Agisoft Photoscan was used to compare the results and then they were compared with the images scanned using CloudCompare software. Thus, following the performance, with the help of the mentioned software, of a series of processing of the point cloud obtained, through the two imaging technologies, the error between the points belonging to the point cloud taken with UAV and the one taken with Laser Scanner was between 1 and 15 mm, the margin of error being acceptable for monuments without complex architectural details, so that the point cloud resulting from UAVs can be used successfully in this activity. The aim of the paper is to elaborate a geomatic methodology with an optimized cost-quality ratio, later replicable in the analysis of the current state of other constructions of the same type, knowing that over 600 castles in Transylvania alone are in a similar state, and such cases can be found in other Central European states as well.

Author(s):  
V. E. Oniga ◽  
A. I. Breaban ◽  
E. I. Alexe ◽  
C. Văsii

Abstract. Indoor mapping and modelling is an important research subject with application in a wide range of domains including interior design, real estate, cultural heritage conservation and restoration. There are multiple sensors applicable for 3D indoor modelling, but the laser scanning technique is frequently used because of the acquisition time, detailed information and accuracy. In this paper, the efficiency of the Maptek I-Site 8820 terrestrial scanner, which is a long-range laser scanner and the accuracy of a HMLS point cloud acquired with a mobile scanner, namely GeoSlam Zeb Horizon were tested for indoor mapping. Aula Magna “Carmen Silva” of the “Gheorghe Asachi” Technical University of Iasi is studied in the current paper since the auditorium interior creates a distinct environment that combines complex geometric structures with architectural lighting and for preserving its great cultural value, the monument has a national historical significance. The registration process of the TLS point clouds was done using two methods: a semi-automatic one with artificial targets and a completely automatic one, based on Iterative Closest Point (ICP) algorithm. The resulted TLS point cloud was analysed in relation to the HMLS point cloud by computing the M3C2 (Multiscale Model to Model Cloud Comparison), obtaining a standard deviation of 2.1 cm and by investigating the Hausdorff distances from which resulted a standard deviation (σ) of 1.6 cm. Cross-sections have been extracted from the HMLS and TLS point clouds and after comparing the sections, 80% of the sigma values are less or equal to 1 cm. The results show high potential of using HMLS and also a long-range laser scanner for 3D modelling of complex scenes, the occlusion effect in the case of TLS being only 5% of the scanned area.


Author(s):  
S. Chiarini ◽  
S. Cremonesi ◽  
L. Fregonese ◽  
F. Fassi ◽  
L. Taffurelli

In this paper, a Cultural Heritage survey, performed by employing and integrating different type of acquisition technologies (imagebased and active sensor based) is presented. The aim of the survey is to create a 3D multiscale database, therefore, different restitution scales, from the architectural-urban one to a detail one are taken in consideration. This research is part of a project financed by the Unesco for the study of historical gardens located in Mantua and Sabbioneta, and in particular for the <i>Palazzo Te</i> renaissance gardens in Mantua, which are reported in this paper. First of all, a general survey of the area has been realized by employing the classical aerial photogrammetry in order to provide the actual arboreal and urban furniture conditions of the gardens (1:500 scale). Next, a detailed photogrammetric survey of the Esedra courtyard in <i>Palazzo Te</i> has been performed by using a UAV system. At the end, laser scanning and traditional topography have been used for the terrestrial detailed acquisition of gardens and architectural façades (1:50&ndash;1:20 scale). The aim of this research is to create a suitable graphical documentation support for the study of the structure of the gardens, to analyze how they have been modified over the years and as an effective support for eventual future re-design. Moreover, the research has involved a certain number of botanic and archeological investigations, which have been duly acquired and modeled with image based systems.<br><br> Starting from the acquired datasets with their acquisition scales, a series of comparative analysis have been performed, especially for those areas in which all the systems have been employed. The comparisons have been extracted by analyzing point cloud models obtained by using a topographical network.<br><br> As a result, the multi-range approach efficiency, obtained by employing the actual available technologies have been illustrated in the present work.


Author(s):  
M. Balzani ◽  
F. Maietti ◽  
B. Mugayar Kühl

Documentation of cultural assets through improved acquisition processes for advanced 3D modelling is one of the main challenges to be faced in order to address, through digital representation, advanced analysis on shape, appearance and conservation condition of cultural heritage. 3D modelling can originate new avenues in the way tangible cultural heritage is studied, visualized, curated, displayed and monitored, improving key features such as analysis and visualization of material degradation and state of conservation. An applied research focused on the analysis of surface specifications and material properties by means of 3D laser scanner survey has been developed within the project of Digital Preservation of FAUUSP building, Faculdade de Arquitetura e Urbanismo da Universidade de São Paulo, Brazil. The integrated 3D survey has been performed by the DIAPReM Center of the Department of Architecture of the University of Ferrara in cooperation with the FAUUSP. The 3D survey has allowed the realization of a point cloud model of the external surfaces, as the basis to investigate in detail the formal characteristics, geometric textures and surface features. The digital geometric model was also the basis for processing the intensity values acquired by laser scanning instrument; this method of analysis was an essential integration to the macroscopic investigations in order to manage additional information related to surface characteristics displayable on the point cloud.


Author(s):  
S. Peterson ◽  
J. Lopez ◽  
R. Munjy

<p><strong>Abstract.</strong> A small unmanned aerial vehicle (UAV) with survey-grade GNSS positioning is used to produce a point cloud for topographic mapping and 3D reconstruction. The objective of this study is to assess the accuracy of a UAV imagery-derived point cloud by comparing a point cloud generated by terrestrial laser scanning (TLS). Imagery was collected over a 320&amp;thinsp;m by 320&amp;thinsp;m area with undulating terrain, containing 80 ground control points. A SenseFly eBee Plus fixed-wing platform with PPK positioning with a 10.6&amp;thinsp;mm focal length and a 20&amp;thinsp;MP digital camera was used to fly the area. Pix4Dmapper, a computer vision based commercial software, was used to process a photogrammetric block, constrained by 5 GCPs while obtaining cm-level RMSE based on the remaining 75 checkpoints. Based on results of automatic aerial triangulation, a point cloud and digital surface model (DSM) (2.5&amp;thinsp;cm/pixel) are generated and their accuracy assessed. A bias less than 1 pixel was observed in elevations from the UAV DSM at the checkpoints. 31 registered TLS scans made up a point cloud of the same area with an observed horizontal root mean square error (RMSE) of 0.006m, and negligible vertical RMSE. Comparisons were made between fitted planes of extracted roof features of 2 buildings and centreline profile comparison of a road in both UAV and TLS point clouds. Comparisons showed an average +8&amp;thinsp;cm bias with UAV point cloud computing too high in two features. No bias was observed in the roof features of the southernmost building.</p>


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1228
Author(s):  
Ting On Chan ◽  
Linyuan Xia ◽  
Yimin Chen ◽  
Wei Lang ◽  
Tingting Chen ◽  
...  

Ancient pagodas are usually parts of hot tourist spots in many oriental countries due to their unique historical backgrounds. They are usually polygonal structures comprised by multiple floors, which are separated by eaves. In this paper, we propose a new method to investigate both the rotational and reflectional symmetry of such polygonal pagodas through developing novel geometric models to fit to the 3D point clouds obtained from photogrammetric reconstruction. The geometric model consists of multiple polygonal pyramid/prism models but has a common central axis. The method was verified by four datasets collected by an unmanned aerial vehicle (UAV) and a hand-held digital camera. The results indicate that the models fit accurately to the pagodas’ point clouds. The symmetry was realized by rotating and reflecting the pagodas’ point clouds after a complete leveling of the point cloud was achieved using the estimated central axes. The results show that there are RMSEs of 5.04 cm and 5.20 cm deviated from the perfect (theoretical) rotational and reflectional symmetries, respectively. This concludes that the examined pagodas are highly symmetric, both rotationally and reflectionally. The concept presented in the paper not only work for polygonal pagodas, but it can also be readily transformed and implemented for other applications for other pagoda-like objects such as transmission towers.


2021 ◽  
Vol 10 (6) ◽  
pp. 367
Author(s):  
Simoni Alexiou ◽  
Georgios Deligiannakis ◽  
Aggelos Pallikarakis ◽  
Ioannis Papanikolaou ◽  
Emmanouil Psomiadis ◽  
...  

Analysis of two small semi-mountainous catchments in central Evia island, Greece, highlights the advantages of Unmanned Aerial Vehicle (UAV) and Terrestrial Laser Scanning (TLS) based change detection methods. We use point clouds derived by both methods in two sites (S1 & S2), to analyse the effects of a recent wildfire on soil erosion. Results indicate that topsoil’s movements in the order of a few centimetres, occurring within a few months, can be estimated. Erosion at S2 is precisely delineated by both methods, yielding a mean value of 1.5 cm within four months. At S1, UAV-derived point clouds’ comparison quantifies annual soil erosion more accurately, showing a maximum annual erosion rate of 48 cm. UAV-derived point clouds appear to be more accurate for channel erosion display and measurement, while the slope wash is more precisely estimated using TLS. Analysis of Point Cloud time series is a reliable and fast process for soil erosion assessment, especially in rapidly changing environments with difficult access for direct measurement methods. This study will contribute to proper georesource management by defining the best-suited methodology for soil erosion assessment after a wildfire in Mediterranean environments.


Author(s):  
M. Campi ◽  
A. di Luggo ◽  
S. Scandurra

The object of this paper is one of the most ancient palaces of Naples, Palazzo Penne, a fourteenth-century residential building located on a small high ground which originally was in the outer fringe of the built up area in a privileged position enabling to enjoy the landscape and gulf beauty. This building, which today is in the heart of the historical center, was the subject of an extensive analysis and documentary research, as well as of metric laser scanner survey carried out by the group researchers working at the Interdepartmental Centre of Research Urban Eco of the University of Naples Federico II. <br><br> Starting from <i>scan to bim</i> systems the creation of a parametric model of the current state of the building is completed, by bringing the point cloud elements back to objects to which historical and construction data can be associated. <br><br> Moreover starting from acquired data, the 3D model shows the reconstructive hypothesis of the original structure and the virtual reconstruction of the building based on traces found on-site and on the comparison with coeval creations allowing to properly hypothesize the design of point features.


2021 ◽  
Vol 12 (24) ◽  
pp. 115
Author(s):  
Diego Francisco García-Molina ◽  
Ramón González-Merino ◽  
Jesús Rodero-Pérez ◽  
Bartolomé Carrasco-Hurtado

<p class="VARKeywords">One of the main objectives of heritage management policies is to promote measures aimed at the maintenance, restoration and enhancement of cultural and archaeological assets. To guarantee this, the responsible institutions must promote actions for the dissemination and transference of cultural heritage, as well as promoting actions with the greatest possible rigour, developing scientific and technical studies that support and improve intervention methods. Recent technological advances in fields such as photogrammetry, digital terrestrial scanning and 3D modelling have made a significant contribution to the digital preservation and dissemination of architectural heritage.</p><p class="VARKeywords">European administrations, in their desire of regional development, as well as the central or local governments have notably boosted the recovery of their rich and diverse heritage. A particular case is Priego de Cordoba’s Castle, a stronghold which was one of the most important monumental icons of the Andalusian period.</p><p class="VARKeywords">Currently, this site is the main target of many architectural interventions and a model due to the implementation of last generation techniques in digital preservation. The local archaeological department promotes a large number of interventions and archaeological excavations. This has made a priority to get a qualitative geometrical 3D documentation, and therefore a constantly updated the point cloud (xyzRGB).</p><p class="VARKeywords">This paper is focussed on presenting the results of the digital preservation process through 2D planimetry obtained from photogrammetric technics, 3D models, and geospatial data. These techniques are a previous step to large architectonical intervention planned in Priego de Cordoba’s Castle, in particular, the identified structures as Wall 1 and Tower 1.</p><p class="VARKeywords">Two out of the three studied structures can be found in Wall 1. They correspond to a cobblestone pavement located in the rampart of the Wall 1, which is a post-medieval period; a double-stepped semi-underground path, excavated in the infill of the wall. The third structure studied in this paper consists of a well, which drills vertically the infill of the wall of the Tower 1. This feature is interpreted in the last research as a vertical well to place the weights of the clock sited in this tower until the 19th century.</p><p class="VARKeywords">This work combines two techniques of geometric documentation to obtain a more complete point cloud. The terrestrial laser scanning, and the photogrammetry due to the higher colour performance, along with the completion of the point cloud obtained with the laser scanner. Along with this study, we will analyse the features which will better define the best technique to fit the documentation of the different structures. Their geometric characteristics, the incidence of sunlight or the accessibility will condition the use and choice of the technique.</p><p class="VARKeywords">We have stated that there is software nowadays which makes it easier to access and consult the information through new computing hardware. Besides, we have highlighted the importance of knowledge and synergy from the different stakeholders implied (city council, technological centre and private companies). The final goal consists of making the society aware of the capital importance of digital preservation as well as dissemination of science.</p>


Author(s):  
V. Lambey ◽  
A. D. Prasad

<p><strong>Abstract.</strong> Photogrammetric surveying with the use of Unmanned Aerial Vehicles (UAV) have gained vast popularity in short span. UAV have the potential to provide imagery at an extraordinary spatial and temporal resolution when coupled with remote sensing. Currently, UAV platforms are fastest and easiest source of data for mapping and 3D modelling. It is to be considered as a low-cost substitute to the traditional airborne photogrammetry. In the present study, UAV applications are explored in terms of 3D modelling, visualization and parameter calculations. National Institute of Technology Raipur, Raipur is chosen as study area and high resolution images are acquired from the UAV with 85% overlap. 3D model is processed through the point cloud generated for the UAV images. The results are compared with traditional methods for validation. The average accuracy obtained for elevation points and area is 97.99% and 97.75%. The study proves that UAV based surveying is an economical alternative in terms of money, time and resources, when compared to the classical aerial photogrammetry methods.</p>


2020 ◽  
Vol 50 (10) ◽  
pp. 1012-1024
Author(s):  
Meimei Wang ◽  
Jiayuan Lin

Individual tree height (ITH) is one of the most important vertical structure parameters of a forest. Field measurement and laser scanning are very expensive for large forests. In this paper, we propose a cost-effective method to acquire ITHs in a forest using the optical overlapping images captured by an unmanned aerial vehicle (UAV). The data sets, including a point cloud, a digital surface model (DSM), and a digital orthorectified map (DOM), were produced from the UAV imagery. The canopy height model (CHM) was obtained by subtracting the digital elevation model (DEM) from the DSM removed of low vegetation. Object-based image analysis was used to extract individual tree crowns (ITCs) from the DOM, and ITHs were initially extracted by overlaying ITC outlines on the CHM. As the extracted ITHs were generally slightly shorter than the measured ITHs, a linear relationship was established between them. The final ITHs of the test site were retrieved by inputting extracted ITHs into the linear regression model. As a result, the coefficient of determination (R2), the root mean square error (RMSE), the mean absolute error (MAE), and the mean relative error (MRE) of the retrieved ITHs against the measured ITHs were 0.92, 1.08 m, 0.76 m, and 0.08, respectively.


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