3DMADMAC|AUTOMATED: synergistic hardware and software solution for automated 3D digitization of cultural heritage objects

In this article a fully automated 3D shape measurement system and data processing algorithms are presented. Main purpose of this system is to automatically (without any user intervention) and rapidly (at least ten times faster than manual measurement) digitize whole object’s surface with some limitations to its properties: maximum measurement volume is described as a cylinder with 2,8m height and 0,6m radius, maximum object's weight is 2 tons.  Measurement head is automatically calibrated by the system for chosen working volume (from 120mm x 80mm x 60mm and ends up to 1,2m x 0,8m x 0,6m). Positioning of measurement head in relation to measured object is realized by computer-controlled manipulator. The system is equipped with two independent collision detection modules to prevent damaging measured object with moving sensor’s head. Measurement process is divided into three steps. First step is used for locating any part of object’s surface in assumed measurement volume. Second step is related to calculation of "next best view" position of measurement head on the base of existing 3D scans. Finally small holes in measured 3D surface are detected and measured. All 3D data processing (filtering, ICP based fitting and final views integration) is performed automatically. Final 3D model is created on the base of user specified parameters like accuracy of surface representation and/or density of surface sampling. In the last section of the paper, exemplary measurement result of two objects: biscuit (from the collection of Museum Palace at Wilanów) and Roman votive altar (Lower Moesia, II-III AD) are presented

Digitalización masiva en 3D: un hito para la documentación arqueológica

[EN] In the heritage field, the demand for fast and efficient 3D digitization technologies for historic remains is increasing. Besides, 3D digitization has proved to be a promising approach to enable precise reconstructions of objects. Yet, unlike the digital acquisition of cultural goods in 2D widely used today, 3D digitization often still requires a significant investment of time and money. To make it more widely available to heritage institutions, the Competence Center for Cultural Heritage Digitization at the Fraunhofer Institute for Computer Graphics Research IGD has developed CultLab3D, the world’s first 3D mass digitization facility for collections of three-dimensional objects. CultLab3D is specifically designed to automate the entire 3D digitization process thus allowing to scan and archive objects on a large-scale. Moreover, scanning and lighting technologies are combined to capture the exact geometry, texture, and optical material properties of artefacts to produce highly accurate photo-realistic representations. The unique setup allows to shorten the time needed for digitization to several minutes per artefact instead of hours, as required by conventional 3D scanning methods.[ES] La demanda de tecnologías rápidas y eficientes en el área de digitalización en tercera dimensión para el legado cultural, se encuentra en constante crecimiento. La digitalización en tercera dimensión ha mostrado ser una aproximación prometedora que garantiza una precisa reconstrucción de objetos. Sin embargo, en comparación con la adquisición de objetos culturales en 2D, ampliamente utilizados en la actualidad, la digitalización en tercera dimensión aún requiere de una inversión significativa de tiempo y dinero. Para facilitar su acceso a instituciones enfocadas a salvaguardar el legado cultural, el Centro de Competencia para la Digitalización del Legado Cultural (Competence Center for Cultural Heritage Digitization) del Instituto Fraunhofer, Computer Graphics Research IGD, desarrolló CultLab3D. CultLab3D es la primerainstancia a nivel mundial que cuenta con un sistema totalmente automatizado para la digitalización masiva de colecciones de objetos tridimensionales. CultLab3D se diseñó específicamente para automatizar los procesos de digitalización en tercera dimension, permitendo escanear y archivar objetos a larga escala. Además, tecnologías de escaneado e iluminación han sido igualmente combinadas para la captura de geometrías exactas, textura y propiedades ópticas del material que constituyen los artefactos en cuestión, con el objetivo de producir representaciones foto-realísticas altamente precisas. Esta construcción única permite la reducción del tiempo requerido por métodos convencionales para la digitalización en tercera dimensión, siendo necesario solamente algunos minutos en lugar de varias horas.CultLab3D was funded by the German Federal Ministry for Economic Affairs and Energy under grant agreement 01MT12022E and Fraunhofer strategic funds.Santos, P.; Ritz, M.; Fuhrmann, C.; Fellner, D. (2017). 3D mass digitization: a milestone for archeological documentation. Virtual Archaeology Review. 8(16):1-11. https://doi.org/10.4995/var.2017.6321SWORD11181

Development of a Robotic Positioning and Tracking System for a Research Laboratory

Measurement of residual stress using neutron or synchrotron diffraction relies on the accurate alignment of the sample in relation to the gauge volume of the instrument. Automatic sample alignment can be achieved using kinematic models of the positioning system provided the relevant kinematic parameters are known, or can be determined, to a suitable accuracy. The main problem addressed in this thesis is improving the repeatability and accuracy of the sample positioning for the strain scanning, through the use of techniques from robotic calibration theory to generate kinematic models of both off-the-shelf and custom-built positioning systems. The approach is illustrated using a positioning system in use on the ENGIN-X instrument at the UK’s ISIS pulsed neutron source comprising a traditional XYZΩ table augmented with a triple axis manipulator. Accuracies better than 100microns were achieved for this compound system. Although discussed here in terms of sample positioning systems these methods are entirely applicable to other moving instrument components such as beam shaping jaws and detectors. Several factors could lead to inaccurate positioning on a neutron or synchrotron diffractometer. It is therefore essential to validate the accuracy of positioning especially during experiments which require a high level of accuracy. In this thesis, a stereo camera system is developed to monitor the sample and other moving parts of the diffractometer. The camera metrology system is designed to measure the positions of retroreflective markers attached to any object that is being monitored. A fully automated camera calibration procedure is developed with an emphasis on accuracy. The potential accuracy of this system is demonstrated and problems that limit accuracy are discussed. It is anticipated that the camera system would be used to correct the positioning system when the error is minimal or notify the user of the error when it is significant

Development and optimization of the control software for a mobile computed tomography system for cultural heritage.

In quest’elaborato sono descritti l’ottimizzazione e lo sviluppo del software di controllo di un apparato tomografico con sorgente di raggi X per analisi nel campo di Beni Artistici e Culturali. In particolare, il lavoro è stato effettuato sul software preesistente di un sistema mobile in uso presso il Dipartimento di Fisica e Astronomia per indagini tomografiche. Il sistema, sviluppato nell’arco di più anni, consiste di un tubo a raggi X, un detector flat-panel e una tavola rotativa per la tomografia. Tre assi traslazionali consentono il movimento di detector e sorgente, ottenendo un'area scansionabile di 1,5×1,5 m². Il software di controllo si occupa dell’intero processo di acquisizione: gestisce il movimento degli assi, effettua la rotazione della tavola che sostiene l’oggetto durante la tomografia e controlla la scheda di acquisizione in comunicazione con il detector per la cattura delle immagini. Con l’upgrade sviluppato in questo lavoro vengono introdotte diverse routine automatizzate e una più comoda gestione delle regioni di interesse per la scansione radio-tomografica, con lo scopo di alleggerire il carico dell’operatore e ridurre i tempi di acquisizione. Il lavoro di tesi si conclude con un’indagine presso Palazzo Vecchio a Firenze in cui sono state effettuate analisi radiografiche e tomografiche di una serie di dipinti su tavola attribuiti in buona parte al Pontormo. In quest’occasione il software aggiornato è stato testato sul campo per verificarne la praticità e l’efficienza delle nuove funzioni. L’esperienza ha messo in evidenza alcuni problemi e carenze del software e del sistema stesso che suggeriscono l’opportunità di un certo numero di aggiornamenti e di una eventuale riscrittura del codice. Nonostante ciò, l’automatizzazione delle operazioni di acquisizione radiografica e tomografica si è rivelata efficace, riducendo il numero di interventi manuali richiesti e con essi il tempo necessario per l’analisi stessa

Laser Scanner Technology

Laser scanning technology plays an important role in the science and engineering arena. The aim of the scanning is usually to create a digital version of the object surface. Multiple scanning is sometimes performed via multiple cameras to obtain all slides of the scene under study. Usually, optical tests are used to elucidate the power of laser scanning technology in the modern industry and in the research laboratories. This book describes the recent contributions reported by laser scanning technology in different areas around the world. The main topics of laser scanning described in this volume include full body scanning, traffic management, 3D survey process, bridge monitoring, tracking of scanning, human sensing, three-dimensional modelling, glacier monitoring and digitizing heritage monuments

Integration of Terrestrial Laser Scanning and UAS Photogrammetry in Geological Studies: Examples from Croatia

Terrestrial laser scanning (TLS) in combination with Unmanned Aircraft System (UAS) and modern computer based photogrammetry is currently the best approach for the acquisition of high-resolution 3D spatial information. Highly realistic 3D spatial data sets are becoming the basis for detailed geological studies, providing a multidisciplinary approach in the study and research of both underground and above ground sites. To emphasize the variety of possible implementations of these state-of-the-art methodologies, four characteristic and yet quite different case studies are presented where such geodetic techniques are successfully employed. The presented case studies demonstrate that TLS and UAS photogrammetry, as non-contact surveying methods, are able to reduce survey time and total project costs. As added value, they provide high-resolution data that can be analyzed in a virtual environment from a sedimentological or structural aspect. Stored digital documentation also allows future multi-temporal spatial data comparison at any timeframe and scale, thus enhancing any target geological data gathering and analyses at the studied sites

Modeling and Simulation in Engineering

This book provides an open platform to establish and share knowledge developed by scholars, scientists, and engineers from all over the world, about various applications of the modeling and simulation in the design process of products, in various engineering fields. The book consists of 12 chapters arranged in two sections (3D Modeling and Virtual Prototyping), reflecting the multidimensionality of applications related to modeling and simulation. Some of the most recent modeling and simulation techniques, as well as some of the most accurate and sophisticated software in treating complex systems, are applied. All the original contributions in this book are jointed by the basic principle of a successful modeling and simulation process: as complex as necessary, and as simple as possible. The idea is to manipulate the simplifying assumptions in a way that reduces the complexity of the model (in order to make a real-time simulation), but without altering the precision of the results

Spatial Centering of a Quadcopter in an Underground Coal Mine

The recent proliferation of smaller and more affordable sensing and computing has contributed to an increased availability of unmanned aerial vehicles, UAV\u27s. Specifically, quadrotor platforms have become popular due to their low cost, versatility, and relative ease of operation. There are a variety of applications for this type of aerial vehicle, ranging from hobbyist photography to search and rescue operations. This thesis documents the feasibility of using a quadrotor UAV within the confined space of an underground coal mine during an emergency. Additionally, this paper notes in the Appendix an experiment to remotely operate a quadcopter that is located underground. This work specifies the equipment used to operate down an eight inch borehole in terms of radios, fiber optic cables, and video hardware. The operator and quadcopter were located 50 feet apart in the experiment.;One of the most significant challenges of operating a quadcopter in an underground coal mine is collision avoidance. The automation of basic spatial centering in the underground coal mine would lessen the burden on the operator and help prevent collisions. Many spatially aware quadcopter systems already exist, but widely rely on GPS signals as a way to determine position. GPS signals are very weak radio signals that cannot penetrate into the earth. The below-ground nature of an underground coal mine precludes the use of GPS for positioning the craft. Due to this limitation, it became necessary to explore unique sensing solutions that would allow for the spatial centering of the quadcopter while operating in an underground environment.;The ability for the craft to maintain a distance from its surroundings through the use of a light-based sensor was analyzed. Sensors were placed on the bottom and side of the quadcopter, and the performance of the control system was observed. Altitude was maintained with a steady state error of 4%, and the response to a step change in ground height resulted in a 10% lower overshoot than simulation. Simultaneously, distance was maintained from the side with a steady state error of 7.8%. The work presented in this document serves as validation for the basic spatial awareness and crash avoidance capability of a quadcopter operating without GPS in an underground coal mine while controlled remotely down an eight inch borehole

Automatic segmentation and reconstruction of traffic accident scenarios from mobile laser scanning data

Virtual reconstruction of historic sites, planning of restorations and attachments of new building parts, as well as forest inventory are few examples of fields that benefit from the application of 3D surveying data. Originally using 2D photo based documentation and manual distance measurements, the 3D information obtained from multi camera and laser scanning systems realizes a noticeable improvement regarding the surveying times and the amount of generated 3D information. The 3D data allows a detailed post processing and better visualization of all relevant spatial information. Yet, for the extraction of the required information from the raw scan data and for the generation of useable visual output, time-consuming, complex user-based data processing is still required, using the commercially available 3D software tools. In this context, the automatic object recognition from 3D point cloud and depth data has been discussed in many different works. The developed tools and methods however, usually only focus on a certain kind of object or the detection of learned invariant surface shapes. Although the resulting methods are applicable for certain practices of data segmentation, they are not necessarily suitable for arbitrary tasks due to the varying requirements of the different fields of research. This thesis presents a more widespread solution for automatic scene reconstruction from 3D point clouds, targeting street scenarios, specifically for the task of traffic accident scene analysis and documentation. The data, obtained by sampling the scene using a mobile scanning system is evaluated, segmented, and finally used to generate detailed 3D information of the scanned environment. To realize this aim, this work adapts and validates various existing approaches on laser scan segmentation regarding the application on accident relevant scene information, including road surfaces and markings, vehicles, walls, trees and other salient objects. The approaches are therefore evaluated regarding their suitability and limitations for the given tasks, as well as for possibilities concerning the combined application together with other procedures. The obtained knowledge is used for the development of new algorithms and procedures to allow a satisfying segmentation and reconstruction of the scene, corresponding to the available sampling densities and precisions. Besides the segmentation of the point cloud data, this thesis presents different visualization and reconstruction methods to achieve a wider range of possible applications of the developed system for data export and utilization in different third party software tools