Virtual Modelling of Prehistoric Sites and Artefacts by Automatic Point-Cloud Surveys

2011 ◽  
pp. 201-217
Author(s):  
Mercedes Farjas ◽  
Francisco J. García-Lázaro ◽  
Julio Zancajo ◽  
Teresa Mostaza ◽  
Nieves Quesada
Keyword(s):  
Initial Data ◽  
Research Group ◽  
Point Cloud ◽  
Laser Scanner ◽  
New Method ◽  
Surface Model ◽  
Digital Surface Model ◽  
Automatic Data ◽  
Operational Costs ◽  
New Methodologies

This chapter presents laser scanner systems as a new method of automatic data acquisition for use in archaeological research. The operation of the equipment is briefly described and results are presented from its application in two Spanish archaelogical sites: Abrigo de Buendía (Cuenca), Atapuerca (Burgos). Together with these systems, point cloud measuring photogrammetric methods are revised. Photogrammetry has been widely used in heritage documentation and in no way is to be relegated by the new scanning techniques. Instead, Photogrammetry upgrades its methods by applying digital approaches so that it becomes competitive in both, operational costs and results. Nevertheless, Photogrammetry and laser scanner systems should be regarded as complementary rather than competing techniques. To illustrate photogrammetric methods their application to generate the Digital Surface Model of an epigraph is described. The authors’ research group endeavours to combine teaching and research in its different fields of activity. Initial data are acquired in project-based teaching situations and international seminars or other activities. Students thus have the opportunity to become familiar with new methodologies while collecting material for analytical studies.

Detection of Building in Airborne Laser Scanner Data and Aerial Images

2012 ◽  
Vol 11 ◽  
pp. 7-13
Author(s):  
Dilli Raj Bhandari
Keyword(s):  
Point Cloud ◽  
Laser Scanner ◽  
Aerial Images ◽  
Spectral Information ◽  
Surface Model ◽  
World Population ◽  
Data Sets ◽  
Scanner Data ◽  
Airborne Laser Scanner ◽  
Airborne Laser

The automatic extraction of the objects from airborne laser scanner data and aerial images has been a topic of research for decades. Airborne laser scanner data are very efficient source for the detection of the buildings. Half of the world population lives in urban/suburban areas, so detailed, accurate and up-to-date building information is of great importance to every resident, government agencies, and private companies. The main objective of this paper is to extract the features for the detection of building using airborne laser scanner data and aerial images. To achieve this objective, a method of integration both LiDAR and aerial images has been explored: thus the advantages of both data sets are utilized to derive the buildings with high accuracy. Airborne laser scanner data contains accurate elevation information in high resolution which is very important feature to detect the elevated objects like buildings and the aerial image has spectral information and this spectral information is an appropriate feature to separate buildings from the trees. Planner region growing segmentation of LiDAR point cloud has been performed and normalized digital surface model (nDSM) is obtained by subtracting DTM from the DSM. Integration of the nDSM, aerial images and the segmented polygon features from the LiDAR point cloud has been carried out. The optimal features for the building detection have been extracted from the integration result. Mean height value of the nDSM, Normalized difference vegetation index (NDVI) and the standard deviation of the nDSM are the effective features. The accuracy assessment of the classification results obtained using the calculated attributes was done. Assessment result yielded an accuracy of almost 92 % explaining the features which are extracted by integrating the two data sets was large extent, effective for the automatic detection of the buildings.

scholarly journals POTENTIAL OF FULL WAVEFORM AIRBORNE LASER SCANNING DATA FOR URBAN AREA CLASSIFICATION – TRANSFER OF CLASSIFICATION APPROACHES BETWEEN MISSIONS

2015 ◽  
Vol XL-7/W3 ◽  
pp. 1317-1323 ◽  
Author(s):  
G. Tran ◽  
D. Nguyen ◽  
M. Milenkovic ◽  
N. Pfeifer
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Point Clouds ◽  
Surface Model ◽  
Knowledge Based ◽  
Full Waveform ◽  
Airborne Laser ◽  
Point Density ◽  
Area Classification

Full-waveform (FWF) LiDAR (Light Detection and Ranging) systems have their advantage in recording the entire backscattered signal of each emitted laser pulse compared to conventional airborne discrete-return laser scanner systems. The FWF systems can provide point clouds which contain extra attributes like amplitude and echo width, etc. In this study, a FWF data collected in 2010 for Eisenstadt, a city in the eastern part of Austria was used to classify four main classes: buildings, trees, waterbody and ground by employing a decision tree. Point density, echo ratio, echo width, normalised digital surface model and point cloud roughness are the main inputs for classification. The accuracy of the final results, correctness and completeness measures, were assessed by comparison of the classified output to a knowledge-based labelling of the points. Completeness and correctness between 90% and 97% was reached, depending on the class. While such results and methods were presented before, we are investigating additionally the transferability of the classification method (features, thresholds …) to another urban FWF lidar point cloud. Our conclusions are that from the features used, only echo width requires new thresholds. A data-driven adaptation of thresholds is suggested.

scholarly journals Pemanfaatan Teknologi Terestrial Laser Scanner Untuk Perekaman Data dan Pendokumentasian Tiga Dimensi (3D) Lukisan Cadas Pada Gua-Gua Prasejarah di Indonesia

2016 ◽  
Vol 10 (1) ◽  
pp. 28-38
Author(s):  
Brahmantara Brahmantara
Keyword(s):  
Rock Art ◽  
Laser Scanner ◽  
Surface Model ◽  
Digital Surface Model ◽  
Model Data ◽  
Virtual Tour

Perkembangan teknologi perekaman data cagar budaya khususnya luksian Cadas (Rock Art) telah berkembang dengan pesat seiring dengan perkembangan teknologi digital. Teknik dan metode perekaman data cagar budaya berkembang dari teknik sederhana sampai dengan teknologi mutakhir berbasis digital dengan format tiga dimensi (3D). Teknologi Terestrial Laser Scanner merupakan perangkat digital dengan sasaran perekaman tiga dimensi (3D). Dalam penelitian ini penerapan Teknologi Terestrial Laser Scanner digunakan untuk merekam data geometri gua dan detail lukisan cadas (Rock Art) pada kawasan Karst Sangkulirang Mangkalihat Kutim Kalimantan Timur. Proses registrasi dari masing masing posisi pemindaian (scan world) menghasilkan tingkat akurasi data yang sangat tinggi dengan rata-rata eror dibawah 2mm. Dari hasil pengolahan data didapatkan beberapa output dan beberapa produk akhir yang sangat signifikan seperti gambar 2D, citra 3D, DS0 (digital surface model), data kontur dengan interval sampai 2 cm, animasi dalam format avi dan informasi publikasi dalam bentuk virtual tour 360�. Dari hasil analisa data tingkat akurasi, jumlah output yang dihasilkan dan alokasi waktu yang dibutuhkan untuk proses perekaman data metode perekaman data dengan Teknologi Terestrial Laser Scanner ini sangat efektif untuk digunakan dalam perekaman data dan pendokumentasian cagar budaya khususnya lukisan cadas (rock art).

Digital Surface Model Accuracy Improvement Based on Edge Line Automatic Extraction of Building Laser Point Cloud

2018 ◽  
Vol 55 (1) ◽  
pp. 012803
Author(s):  
苗松 Miao Song ◽  
王建军 Wang Jianjun ◽  
李云龙 Li Yunlong ◽  
范媛媛 Fan Yuanyuan
Keyword(s):  
Point Cloud ◽  
Surface Model ◽  
Automatic Extraction ◽  
Digital Surface Model ◽  
Model Accuracy ◽  
Accuracy Improvement

Research on Reverse Engineering for Blades of Axial Compressors with Laser Scanner

2013 ◽  
Vol 774-776 ◽  
pp. 185-189
Author(s):  
Wei Song ◽  
Xi De Lai ◽  
Guang Fu Li ◽  
Wei Zhang ◽  
Xiao Ming Chen ◽  
...  
Keyword(s):  
Reverse Engineering ◽  
Point Cloud ◽  
Optimization Design ◽  
Laser Scanner ◽  
Axial Compressor ◽  
Surface Model ◽  
Point Cloud Data ◽  
Aerodynamic Optimization ◽  
Cloud Data ◽  
Axial Compressors

To acquire the digital model of axial compressors on the actual projects, a Reverse Engineering procedure of the blade was developed based on point cloud data acquired with the handy laser scanner. For meeting the requirements of geometric characteristics and aerodynamic optimization design and improving acquiring efficiency of point cloud data, the laser triangulation was employed and auxiliary plane and mark points were put on the inlet, outlet and tip of the blade. For solving the problem of low accuracy of fitting surface on the blade, an interactive dividing method of surface slices which based on the streamline, meridian line, contour and its extension line, was presented, it showed that reconstructed surface model can meet the actual projects needs. A completed set of RE technology for axial compressor blades has been developed, and it has been used in actual project combing with the maintenance of a large axial compressor blade.

scholarly journals Automatic Point-Cloud Registration for Quality Control in Building Works

2021 ◽  
Vol 11 (4) ◽  
pp. 1465
Author(s):  
Rocio Mora ◽  
Jose Antonio Martín-Jiménez ◽  
Susana Lagüela ◽  
Diego González-Aguilera
Keyword(s):  
Quality Control ◽  
Coordinate System ◽  
Point Cloud ◽  
Laser Scanner ◽  
Point Clouds ◽  
Automatic Data ◽  
Building Maintenance ◽  
Post Process ◽  
Indoor Scenes ◽  
Construction Tasks

Total and automatic digitalization of indoor spaces in 3D implies a great advance in building maintenance and construction tasks, which currently require visits and manual works. Terrestrial laser scanners (TLS) have been widely used for these tasks, although the acquisition methodology with TLS systems is time consuming, and each point cloud is acquired in a different coordinate system, so the user has to post-process the data to clean and get a unique point cloud of the whole scenario. This paper presents a solution for the automatic data acquisition and registration of point clouds from indoor scenes, designed for point clouds acquired with a terrestrial laser scanner (TLS) mounted on an unmanned ground vehicle (UGV). The methodology developed allows the generation of one complete dense 3D point cloud consisting of the acquired point clouds registered in the same coordinate system, reaching an accuracy below 1 cm in section dimensions and below 1.5 cm in walls thickness, which makes it valid for quality control in building works. Two different study cases corresponding to building works were chosen for the validation of the method, showing the applicability of the methodology developed for tasks related to the control of the evolution of the construction.

scholarly journals Accuracy Evaluation of 3D Geometry from Low-Attitude UAV collections A case at Zijin Mine

2014 ◽  
Vol XL-4 ◽  
pp. 297-300 ◽  
Author(s):  
Q. Wang ◽  
L. Wu ◽  
S. Chen ◽  
D. Shu ◽  
Z. Xu ◽  
...  
Keyword(s):  
Point Cloud ◽  
Laser Scanner ◽  
Experimental Result ◽  
Surface Model ◽  
Accuracy Evaluation ◽  
3D Point Cloud ◽  
Ground Control Points ◽  
Aerial Vehicle ◽  
Modelling Techniques ◽  
Image Modelling

This study investigates the usability of low-attitude unmanned aerial vehicle (UAV) acquiring high resolution images for the geometry reconstruction of opencast mine. Image modelling techniques like Structure from Motion (SfM) and Patch-based Multiview Stereo (PMVS) algorithms are used to generate dense 3D point cloud from UAV collections. Then, precision of 3D point cloud will be first evaluated based on Real-time Kinematic (RTK) ground control points (GCPs) at point level. The experimental result shows that the mean square error of the UAV point cloud is 0.11 m. Digital surface model (DSM) of the study area is generated from UAV point cloud, and compared with that from the Terrestrial Laser Scanner (TLS) data for further comparison at the surface level. Discrepancy map of 3D distances based on DSMs shows that most deviation is less than ±0.4 m and the relative error of the volume is 1.55 %.

scholarly journals Terrestrial Laser Scanner for the Formal Assessment of a Roman-Medieval Structure—The Cloister of the Cathedral of Tarragona (Spain)

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 427
Author(s):  
Felipe Buill ◽  
M. Amparo Núñez-Andrés ◽  
Agustí Costa-Jover ◽  
David Moreno ◽  
Josep M. Puche ◽  
...  
Keyword(s):  
Point Cloud ◽  
Good Condition ◽  
Laser Scanner ◽  
3D Analysis ◽  
Terrestrial Laser Scanner ◽  
Analysis Methodology ◽  
General Terms ◽  
12Th Century ◽  
New Methodologies ◽  
Capture Techniques

The use of massive data capture techniques in architectural heritage has enhanced the development of new methodologies that have an important impact on their conservation and understanding. The research proposes the study of formal anomalies in the cloister of the Cathedral of Tarragona (c. 12th century). It is a relevant Gothic construction in Catalonia, with the special singularity that part of its structure is raised over an important pre-existing Roman wall. The investigation is based on a point cloud obtained with a terrestrial laser scanner (TLS) and the systematization of the 3D analysis methodology of the point cloud through different reference shapes. In general terms, the construction is in good condition, so the discrepancies between real construction and the shapes of reference are small, with some exceptions. Nevertheless, the different approximations used allowed us to identify some relevant features, such as the variability of the form of rib vaults, and the influence of the criteria used in the definition and location of reference forms.

scholarly journals Ekstraksi Digital Surface Model (DSM) dari Data Unmanned Aerial Vehicle (UAV) Berbasis Point Cloud

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Indra Laksana ◽  
R Suharyadi ◽  
M. Pramono Hadi
Keyword(s):  
Data Acquisition ◽  
Point Cloud ◽  
Unmanned Aircraft ◽  
Surface Model ◽  
Digital Surface Model ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Key Points ◽  
Elevation Data ◽  
Data Point

<div class="WordSection1"><p><strong>Abstr</strong><strong>ak. </strong>Akuisisi data dengan menggunakan pesawat tanpa awak semakin sering dilakukan. Penelitian ini memodelkan data elevasi dari pengukuran lapangan dengan menggunakan pesawat tanpa awak. Tujuan dari penelitian ini :(1) untuk menguji kemampuan pesawat tanpa awak dalam mengakuisisi data elevasi, dan (2) untuk membandingkan data elevasi jika ditambahkan data point cloud dan data pengukuran batimetri. Metode pengolahan dengan menggunakan data point cloud dilakukan dengan pertama-tama mencocokkan titik kunci. Pencocokan titik kunci mengkaitkan seluruh hasil foto udara hingga membentuk satu kesatuan area yang telah difoto. Selanjutnya dilakukan penampalan titik ikat pada area yang telah terbentuk dari pencocokan titik kunci. Titik ikat berfungsi sebagai koreksi data pada saat pesawat tanpa awak melakukan pengambilan data. Foto udara yang telah dikoreksi kemudian diolah untuk mendapatkan data <em>point cloud</em>. <em>Point cloud</em> berguna sebagai data penyusun ortofoto dan data <em>Digital Surface Model</em> (DSM). Pengolahan data point cloud hingga menghasilkan DSM dilakukan dengan menggunakan software Pix4D dan Agisoft photoscan. Hasil yang diperoleh menunjukkan bahwa terjadi peningkatan kemampuan DSM ketika data pointcloud ditambahkan data titik ikat dan data pengukuran batimetri. Sehingga dapat disimpulkan bahwa akuisisi data menggunakan pesawat tanpa awak mampu menghasilkan data yang dapat dipercaya. Selain dapat dipercaya akuisisi data dengan pesawat tanpa awak lebih murah jika dibandingkan dengan akuisisi data dengan foto udara.</p><p>Keywords:  digital surface model, pesawat tanpa awak, titik ikat</p><p><strong> </strong></p><p><strong>Abstract. </strong><em>Data acquisition using unmanned aircraft is increasingly being done. This study models elevation data from field measurements using unmanned aircraft. The purpose of this study: (1) to test the ability of unmanned aircraft to acquire elevation data, and (2) to compare elevation data if added point cloud data and bathymetry measurement data. The processing method using point cloud data is done by first matching key points. Matching key points links all aerial photography results to forming a single unit area that has been photographed.</em><em> </em><em>Next, a tie point is carried out in the area formed from matching key points. Tie points function as data correction when unmanned aircraft take data. Corrected aerial photos are then processed to obtain point cloud data.</em><em> </em><em>Point cloud is useful as orthophoto compiler data and Digital Surface Model (DSM) data.</em><em> </em><em>Point cloud data processing to produce DSM is done using Pix4D and Agisoft photoscan software.</em><em>The results obtained showed that there was an increase in DSM capabilities when point cloud data was added to the tie point data and bathymetry measurement data. So, it can be concluded that data acquisition using unmanned aircraft is able to produce reliable data. Besides being reliable, data acquisition with unmanned aircraft is cheaper compared to data acquisition with aerial photography.</em></p></div><strong><em>Keywords:</em> </strong>u<em>nmanned aerial vehicle, ground c point, Digital surface model</em><p class="MsoNormal" style="margin-bottom: .0001pt; text-align: justify; text-justify: inter-ideograph;"> </p>

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