Since the last two decades, the use of laser scanners for generating accurate and dense 3D models has been rapidly growing in multiple disciplines. The reliance on human-expertise to perform an ...efficient scanning in terms of completeness and quality encouraged the researchers to develop strategies for carrying out an optimized and automated scan planning. Nevertheless, due to the predominant use of static terrestrial laser scanners (TLS), the most of developed methods have been focused on scan optimization by fixing standpoints on basis of static scanning. The increasing use of portable mobile laser scanning systems (MLS) enables faster non-stop acquisition which demands the planning of optimal scan trajectories. Therefore, a novel method addressing the absence of dynamic scan planning is proposed considering specific MLS constraints such as maximum acquisition time or closed-loops requirement. First, an initial analysis is carried out to determinate key-positions to reach during data acquisition. From these positions a navigable graph is generated to compute routes satisfying specific MLS constraints by a three-step process. This starts by estimating the number of routes necessary to subsequently carry out a coarse graph partition based on Kmedoids clustering. Next, a balancing algorithm was implemented to compute a balanced graph partition by node exchanging. Finally, partitions are extended by adding key nodes from their adjacent ones in order to provide a desirable overlapping between scans. The method was tested by simulating three laser scanner configurations in four indoor and outdoor real case studies. The acquisition quality of the computed scan planning was evaluated in terms of 3D completeness and point cloud density with the simulator Helios++.
•A scan planning tool including optimal routing for both static and mobile scanning.•A graph-partitioning programming formulation for solving balanced closed loops.•A method for route softening towards 3D data quality simulation based on Helios.
Cultural heritage (CH) documentation tasks usually involve professionals from different knowledge areas, which implies not only a huge amount of information and requirements, but also a very ...heterogeneous set of sources, data structures, content and formats. Geographic information systems (GIS) have been used extensively by cultural heritage specialists, but this is just working around the real problem: there is no specialized software for CH professionals to document their work in 3D. In this paper, we present software named Agata that allows specialists to interact in real time with high resolution polygonal models, and to annotate different raster and vectorial information directly onto them that might be useful for current or future research. Moreover, these annotations can be exported in a standard format that allows researchers from other disciplines that might be interested in the dataset to access such information easily. The system is able to manage and annotate not only on buildings or archaeological sites, but also sculptures or paintings directly into the 3D dataset of any CH physical element.
A 3-year pilot project “Towards the Virtual Museum – 3D-digitalization of A-category objects selected from the collection of Archaeological Museum in Zagreb” has a primary objective to enhance the ...accessibility of museum collection to a bigger audience, both scientific and the general public. The project goal is to research existing tools and methods for 3D digitalization and visualization of archaeological objects different in size and material. Digital models achieved by 3D scanning techniques will be equally used for virtual reconstruction, making replicas, scientific analysis and detailed damage recordings on ob- jects and monuments.
This paper presents an efficient solution, based on a wearable mobile laser system (WMLS), for the digitalization and modelling of a complex cultural heritage building. A procedural pipeline is ...formalized for the data acquisition, processing and generation of cartographic products over a XV century palace located in Segovia, Spain. The complexity, represented by an intricate interior space and by the presence of important structural problems, prevents the use of standard protocols such as those based on terrestrial photogrammetry or terrestrial laser scanning, making the WMLS the most suitable and powerful solution for the design of restoration actions. The results obtained corroborate with the robustness and accuracy of the digitalization strategy, allowing for the generation of 3D models and 2D cartographic products with the required level of quality and time needed to digitalize the area by a terrestrial laser scanner.
Digital 3D models of the environment are needed in rescue and inspection robotics, facility managements and architecture. This paper presents an automatic system for gaging and digitalization of 3D ...indoor environments. It consists of an autonomous mobile robot, a reliable 3D laser range finder and three elaborated software modules. The first module, a fast variant of the Iterative Closest Points algorithm, registers the 3D scans in a common coordinate system and relocalizes the robot. The second module, a next best view planner, computes the next nominal pose based on the acquired 3D data while avoiding complicated obstacles. The third module, a closed-loop and globally stable motor controller, navigates the mobile robot to a nominal pose on the base of odometry and avoids collisions with dynamical obstacles. The 3D laser range finder acquires a 3D scan at this pose. The proposed method allows one to digitalize large indoor environments fast and reliably without any intervention and solves the SLAM problem. The results of two 3D digitalization experiments are presented using a fast octree-based visualization method.
Introduction and aim: In recent decades, the whole field of medicine has been undergoing a digital revolution. This phenomenon is making its way into dental fields as well, including orthodontics, ...and gradually more and more workflow procedures are being digitalized. The digital models of dental arches can be obtained with the help of an intraoral scanner, and afterwards, using a 3D printer, they can be transformed into physical models. In the field of orthodontics, dental models are needed as study models for diagnostic analysis and determining the therapeutical plan. Dental models at the end of orthodontic therapy are very important as working models for the production of retention devices. The thermoplastic retention plates are very frequently given to patients as retention apparatus and are very popular among them. They are being manufactured at high temperatures in a vacuum machine in a process also known as vacuuming. Conventionally this manufacturing tends to be performed on classic gypsum models. With the growing popularity of digital dental models and their subsequent 3D printing, it is important to know whether dental models made in this way are also suitable for the production of thermoplastic retention plates. Currently, the most widely used method for 3D printing is called Fused Deposition Modeling, using molten plastics as a material for the printing.The aim of this research was to evaluate 3 thermoplastic materials - ABS, ASA, and Z-Ultrat and to measure their dimensional stability while being exposed to the conditions of vacuuming during the production of the thermoplastic plates. It was important to determine whichof them would retain its dimensional stability under given conditions in the best way.Methods: To obtain the necessary data, we first made intraoral scans of the upper dental arch of two patients using an iTero intraoral scanner. With the use of Zortrax M200 3D printer, these scans were then used to produce physical 3D models. The following parameters were setfor the 3D printing: layer thickness - 0.09 mm, density of the infill - 70%, and orientation of the model in the Z axis - 45°. The physical 3D models were then digitized again with GOM ATOS TripleScan extraoral 3D scanner, placed in a vacuum machine, and then scanned again. GOM Inspectsoftware was used to evaluate the dimensional accuracy of manufactured parts. The maximum clinically acceptable deviation between the first 3D scan and the scan of the physical model after vacuuming was determined by the authors to be +/- 0.50 mm.Results: Dental models from all 3 examined thermoplastic materials have shown a statistically significant change in their dimensions. However, the magnitude of these deviations is acceptable for clinical practice. All models printed from ABS and Z-Ultrat met the maximum clinically permissible deviation of +/- 0.50 mm.Conclusions: Certified material Z-Ultrat, having a chemical composition of PC-ABS, showed the best dimensional stability. Based on the obtained data, it can be concluded that the models of dental arches printed by the FDM method can be used in practice as working models for the production of thermoplastic retention plates.
Additive technologies in construction and architecture are becoming more and more popular. Due to their advantages, concrete extrusion technologies have great potential for the future. One of the ...important parameters is the quality and precision achieved in the entire building process. This study investigates the search for a methodology to verify the quality of three-dimensional (3D) printing from concrete mixtures not just as an indication of the resulting accuracy of the process but to monitor the behavior of the printed object in the period immediately after the printing for a period of 28 days. Research has confirmed, among other things, that one of the main causes of dimensional changes over time is shrinkage, which occurs primarily in the length and height directions of the object. The drying behavior of the material also depends on the thickness of the wall, with the thicker parts of the element shrinking more slowly than the thin and peripheral parts. The research also confirmed the hypothesis that digitization using 3D optical scanning could be used for complex three-dimensional analysis of the dimensional accuracy and dimensional stability of concrete elements produced by 3D printing. However, due to the surface structure of printed objects, specific inspection procedures need to be chosen, which are analyzed and described in this paper.
Digital close-range photogrammetry allows us to acquire high-fidelity tridimensional models useful to document cultural heritage objects with an impressive level of detail. In addition, this ...technique carries a strong analytical potentiality, able to gain improved knowledge of cultural objects and their preservation conditions. This project is focused on a comprehensive diagnostic survey using 3D multispectral modeling, high-resolution digital radiography, pulsed thermography, XRF, FT-IR, and FORS spectroscopies to document and characterize from a conservative point of view the poly-material objects that belong to the “Garnier Valletti” pomological collection—a unique collection from both scientific and artistic points of view. The analytical integration of imaging techniques, 3D modeling, and spectroscopic techniques provides information from the surface, sub-surface, and innermost layers of the object, respectively, capturing both accurate morphometric, spectral, and compositional data. The article presents the results obtained on typical poly-material and multilayered objects of this collection for which the combination of the considered techniques provided important data to the technical knowledge of the realization highlighting a particular predictive ability from a conservative point of view.
Plant shape, and thereby plant architecture, is a major component of the visual quality of ornamental plants. We have been developing a new method for analyzing the entire plant architecture by 3D ...digitalization that allows an almost exhaustive description of rose bush architecture and generates a large number of variables, many of them inaccessible manually. We carried out a QTL analysis using this original phenotyping method. In order to evaluate a broader allelic variability as well as the effect of the genetic background on QTL detection, we used two connected, segregating, recurrent blooming populations. The number of QTLs per variable varied from three for the number of determined axes (NbDetA) to seven for the branching angle of order 2 long axes (AngLA2), the two populations taken together. Five new QTLs, located on the linkage groups (LGs) 2, 6, and 7, were detected for the branching angle of axes, and the QTL located on LG7 co-localized with
RhBRC1
, a branching repressor. Branching and stem elongation QTLs also co-located with
RhBRC1
, suggesting its pleiotropic nature. Year-specific QTLs were also revealed, that explained the genotype × year interactions observed for the number of order 3 short axes (NbSA3) and AngLA2 from a genetic point of view. We also evidenced an effect of the genetic background on QTL detection. This new knowledge should help to better reason the genetic improvement programs for rose bush architecture and, therefore, rose bush shape.
The modern 3D digitalization techniques open new scenarios on how to transmit to the next generations the state of health of Cultural Heritage (CH) buildings, paintings, frescos or statues. The final ...goal of the 3D digitalization is an exact replica of the acquired target, but a standard and unique technique able to digitalize artworks of different size and in different ambient light conditions is still far from being successfully ready for the CH field. Even if both laser scanning and photogrammetry can be considered mature techniques, applied with success in most of the Cultural Heritage study cases, they are limited in terms of colour digitalization and image quality in all the cases where ambient light and big sensor-target distances are crucial factors: differently to standard laser scanners, which collect colour information by the use of a coaxial camera and the distance by an IR laser source, the RGB-ITR (Red, Green and Blue Imaging Topological Radar) scanner, developed in ENEA, is equipped with three different laser sources for the simultaneous colour and distance estimation. The present work shows the results obtained applying the above-mentioned multi-wavelengths laser scanner for collecting a complete high-quality 3D colour model of “The Triumph of Divine Providence” vault, painted by Pietro da Cortona on the ceiling of the noble hall inside Palazzo Barberini in Rome.
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