scholarly journals LASER AND MULTI-IMAGE REVERSE ENGINEERING SYSTEMS FOR ACCURATE 3D MODELLING OF COMPLEX CULTURAL ARTEFACTS

Author(s):  
C. Ioannidis ◽  
G. Piniotis ◽  
S. Soile ◽  
F. Bourexis ◽  
A.-M. Boutsi ◽  
...  

<p><strong>Abstract.</strong> The recent scientific and technical developments of reverse engineering methods and tools have broadened the possibilities of applications in the field of cultural heritage conservation. In this paper, two different non-contact reverse engineering systems were utilized for 3D data acquisition of a cultural heritage artefact. The object of interest is a 17th century wooden engraved ecclesiastical sanctuary ciborium. The requirement of the 3D model is to aid the art conservators for the preservation of the wooden material and the restoration of small damages and cracks in the engraved parts, thus requiring accuracy of the model in the order of sub-millimetre. In this work, a Faro Vantage laser tracker was employed along with the FARO Edge Arm. In addition, image-based modelling was also implemented with a large number of overlapping images acquired with a Canon EOS 6D camera and processed using the well-known Structure from Motion (SfM) method with an auto-calibration procedure. The digital data acquisition and processing procedures of the scanned geometry are described and compared to evaluate the performance of both systems in terms of data acquisition time, processing time, reconstruction precision and final model quality. Whilst models produced with laser scanning and image-based techniques is not a novel approach, the combination of laser tracking and photogrammetric data still presents limited documentation in the field of cultural artefact documentation mainly due to the extremely high cost of the laser tracking systems.</p>

2019 ◽  
Vol 8 (6) ◽  
pp. 285 ◽  
Author(s):  
Balletti ◽  
Ballarin

In recent decades, 3D acquisition by laser scanning or digital photogrammetry has become one of the standard methods of documenting cultural heritage, because it permits one to analyze the shape, geometry, and location of any artefact without necessarily coming into contact with it. The recording of three-dimensional metrical data of an asset allows one to preserve and monitor, but also to understand and explain the history and cultural heritage shared. In essence, it constitutes a digital archive of the state of an artefact, which can be used for various purposes, be remodeled, or kept safely stored. With the introduction of 3D printing, digital data can once again take on material form and become physical objects from the corresponding mathematical models in a relatively short time and often at low cost. This possibility has led to a different consideration of the concept of virtual data, no longer necessarily linked to simple visual fruition. The importance of creating high-resolution physical copies has been reassessed in light of different types of events that increasingly threaten the protection of cultural heritage. The aim of this research is to analyze the critical issues in the production process of the replicas, focusing on potential problems in data acquisition and processing and on the accuracy of the resulting 3D printing. The metric precision of the printed model with 3D technology are fundamental for everything concerning geomatics and must be related to the same characteristics of the digital model obtained through the survey analysis.


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):  
A. Denby ◽  
J. F. Poliakoff ◽  
C. Langensiepen ◽  
N. Sherkat

In CAD/CAM, reverse engineering involves obtaining a CAD model from an object that already exists. An exact replica can then be produced, or modifications can be made before manufacture. Single-perspective triangulation sensors provide an inexpensive method for data acquisition. However, such sensors are subject to localised distortions caused by secondary reflections or occlusion of the returning beam, depending on the orientation of the sensor relative to the object. This chapter describes an investigation into integrating optical camera data to improve the scanning process and reduce such effects, and intelligent algorithms, based on image analysis, which identify the problem regions, so that the sensor path and orientation can be planned before the scan, thereby reducing distortions.


2021 ◽  
Vol 13 (16) ◽  
pp. 3129
Author(s):  
Christoph Gollob ◽  
Tim Ritter ◽  
Ralf Kraßnitzer ◽  
Andreas Tockner ◽  
Arne Nothdurft

The estimation of single tree and complete stand information is one of the central tasks of forest inventory. In recent years, automatic algorithms have been successfully developed for the detection and measurement of trees with laser scanning technology. Nevertheless, most of the forest inventories are nowadays carried out with manual tree measurements using traditional instruments. This is due to the high investment costs for modern laser scanner equipment and, in particular, the time-consuming and incomplete nature of data acquisition with stationary terrestrial laser scanners. Traditionally, forest inventory data are collected through manual surveys with calipers or tapes. Practically, this is both labor and time-consuming. In 2020, Apple implemented a Light Detection and Ranging (LiDAR) sensor in the new Apple iPad Pro (4th Gen) and iPhone Pro 12. Since then, access to LiDAR-generated 3D point clouds has become possible with consumer-level devices. In this study, an Apple iPad Pro was tested to produce 3D point clouds, and its performance was compared with a personal laser scanning (PLS) approach to estimate individual tree parameters in different forest types and structures. Reference data were obtained by traditional measurements on 21 circular forest inventory sample plots with a 7 m radius. The tree mapping with the iPad showed a detection rate of 97.3% compared to 99.5% with the PLS scans for trees with a lower diameter at a breast height (dbh) threshold of 10 cm. The root mean square error (RMSE) of the best dbh measurement out of five different dbh modeling approaches was 3.13 cm with the iPad and 1.59 cm with PLS. The data acquisition time with the iPad was approximately 7.51 min per sample plot; this is twice as long as that with PLS but 2.5 times shorter than that with traditional forest inventory equipment. In conclusion, the proposed forest inventory with the iPad is generally feasible and achieves accurate and precise stem counts and dbh measurements with efficient labor effort compared to traditional approaches. Along with future technological developments, it is expected that other consumer-level handheld devices with integrated laser scanners will also be developed beyond the iPad, which will serve as an accurate and cost-efficient alternative solution to the approved but relatively expensive TLS and PLS systems. Such a development would be mandatory to broadly establish digital technology and fully automated routines in forest inventory practice. Finally, high-level progress is generally expected for the broader scientific community in forest ecosystem monitoring, as the collection of highly precise 3D point cloud data is no longer hindered by financial burdens.


2021 ◽  
Vol 4 (2) ◽  
pp. 13-20
Author(s):  
Mehmood Ahmad ◽  
Sheharyar Nasir ◽  
Zia Ur Rahman ◽  
Shuaib Salamat ◽  
Umar Sajjad ◽  
...  

A rapidly advancing lean production industry demands quick manufacturing solutions with greater precision and accuracy. This paper proposes a framework for the accurate quantification of a die-casted wing using laser scanning and reverse engineering technique. In this technique, the wing upper and lower surfaces are scanned using a Coordinate Measuring Machine (CMM). This scanned data is then imported into CAD software to generate the surface using Free Form Reverse Engineering (FFRE). The model fitness test patronizes the curve fitting used for the surface generation. The generated surface and the original 3D CAD model are investigated using deviation analysis for inaccuracies originating due to manufacturing and data acquisition. The wing is further analyzed by the point data to 3D CAD model deviation analysis. The methodology adopted significantly minimizes the data acquisition and data processing error allowing deviation to be solely traced back to the manufacturing technique.


2020 ◽  
Vol 12 (19) ◽  
pp. 8108
Author(s):  
Namhyuk Ham ◽  
Baek-Il Bae ◽  
Ok-Kyung Yuh

This study proposed a phased reverse engineering framework to construct cultural heritage archives using laser scanning and a building information model (BIM). This framework includes acquisition of point cloud data through laser scanning. Unlike previous studies, in this study, a standard for authoring BIM data was established through comparative analysis of existing archives and point cloud data, and a method of building valuable BIM data as an information model was proposed. From a short-term perspective, additional archives such as member lists and drawings can be extracted from BIM data built as an information model. In addition, from a long-term perspective, a scenario for using the cultural heritage archive consisting of historical records, point cloud data, and BIM data was presented. These scenarios were verified through a case study. In particular, through the BIM data building and management method, relatively very light BIM data (499 MB) could be built based on point cloud data (more than 917 MB), which is a large amount of data.


Author(s):  
Joel V. Silva ◽  
Sérgio L. Costa ◽  
Hélder Puga ◽  
Nuno Peixinho ◽  
João P. Mendonça

One main objective of the technique of reverse engineering is focused on development of new products based on the improvement of existing products. The present work aims to demonstrate a sustainable methodology exploring the capabilities of reverse engineering, applied to produce brand new geometric solutions for safety metallic components incorporated in footwear. The data acquisition is done using different techniques, contact methods (CMM – Measuring Coordinate Machine) and non-contact methods (Laser Scanning). Those measuring techniques for data acquisition are the key entry for the 3D shape recovery, boosting the development of new components based on the improvement of existing products. Despite these techniques being widely explored in multiple engineering sectors, author’s contribute was focused on the proposal and validation of a sustainable methodology based on an algorithm in MATLAB that performs the surface generation under user control. Such methodology has been tested through a real model of a toecap component used in safety footwear.


Author(s):  
S. Gagliolo ◽  
E. Ausonio ◽  
B. Federici ◽  
I. Ferrando ◽  
D. Passoni ◽  
...  

The conservation of Cultural Heritage depends on the availability of means and resources and, consequently, on the possibility to make effective operations of data acquisition. In facts, on the one hand the creation of data repositories allows the description of the present state-of-art, in order to preserve the testimonial value and to permit the fruition. On the other hand, data acquisition grants a metrical knowledge, which is particularly useful for a direct restoration of the surveyed objects, through the analysis of their 3D digital models. In the last decades, the continuous increase and improvement of 3D survey techniques and of tools for the geometric and digital data management have represented a great support to the development of documentary activities. In particular, Photogrammetry is a survey technique highly appropriate in the creation of data repositories in the field of Cultural Heritage, thanks to its advantages of cheapness, flexibility, speed, and the opportunity to ensure the operators’ safety in hazardous areas too. In order to obtain a complete documentation, the high precision of the on-site operations must be coupled with an effective post-processing phase. Hence, a comparison among some of the photogrammetric software currently available was performed by the authors, with a particular attention to the workflow completeness and the final products quality.


Author(s):  
A. Cardaci ◽  
A. Versaci

<p><strong>Abstract.</strong> In our time, new technologies are progressively more and more approaching the cultural heritage's world. The opportunity to obtain – quickly and in a non-invasive way – virtual models of ancient sites, monuments and objects, using data taken by photo-modelling, digital photogrammetry or laser scanning techniques, offers new possibilities for their proper documentation, monitoring, physical conservation, restoration, archiving and valorization. Moreover, reverse engineering techniques allow a deeper understanding of architectural artefacts and collections by increasing their communication, display and interpretation. By showing a number of experiences related to the rich and famous archaeological heritage of Sicily Island, this paper intends to highlight how the use of new digital equipment and methodologies can be of great benefit for its safeguarding, representation, promotion and enjoyment.</p>


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