scholarly journals 3D Scanning of Semitransparent Amber with and without Inclusions

2021 ◽  
Author(s):  
Adam L. Kaczmarek ◽  
Jacek Lebiedź ◽  
Jakub Jaroszewicz ◽  
Wojciech Świeszkowski
Keyword(s):  
Virtual Reality ◽  
Structured Light ◽  
3D Structure ◽  
Laser Scanner ◽  
3D Scanning ◽  
Stereo Camera ◽  
Camera Array ◽  
Semitransparent Material ◽  
Structured Light Scanner ◽  
3D Scans

This paper is concerned with making 3D scans of semitransparent ambers with and without inclusions. The paper presents results of using a variety of devices applied for this purpose. Equipment used in the experiments includes a 3D laser scanner, a structured light scanner, a stereo camera, a camera array and a tomograph. The main object used in the experiment was an amber with a fossil of a lizard. The paper shows possibilities of acquiring the 3D structure of fossils embedded in semitransparent material which interfere with the measurement performed by 3D scanning equipment. Moreover, the paper shows the application of results of 3D scanning as the 3D scan of a lizard was reconstructed in a virtual reality cave making it possible to visualize in detail its shape and texture

scholarly journals Co-registration Comparison of On-Scalp Magnetoencephalography and Magnetic Resonance Imaging

2021 ◽  
Vol 15 ◽  
Author(s):  
Fuzhi Cao ◽  
Nan An ◽  
Weinan Xu ◽  
Wenli Wang ◽  
Yanfei Yang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Source Localization ◽  
Structured Light ◽  
Laser Scanner ◽  
High Signal ◽  
Resonance Imaging ◽  
Registration Error ◽  
Structured Light Scanner ◽  
Reference Phantom

Magnetoencephalography (MEG) can non-invasively measure the electromagnetic activity of the brain. A new type of MEG, on-scalp MEG, has attracted the attention of researchers recently. Compared to the conventional SQUID-MEG, on-scalp MEG constructed with optically pumped magnetometers is wearable and has a high signal-to-noise ratio. While the co-registration between MEG and magnetic resonance imaging (MRI) significantly influences the source localization accuracy, co-registration error requires assessment, and quantification. Recent studies have evaluated the co-registration error of on-scalp MEG mainly based on the surface fit error or the repeatability error of different measurements, which do not reflect the true co-registration error. In this study, a three-dimensional-printed reference phantom was constructed to provide the ground truth of MEG sensor locations and orientations relative to MRI. The co-registration performances of commonly used three devices—electromagnetic digitization system, structured-light scanner, and laser scanner—were compared and quantified by the indices of final co-registration errors in the reference phantom and human experiments. Furthermore, the influence of the co-registration error on the performance of source localization was analyzed via simulations. The laser scanner had the best co-registration accuracy (rotation error of 0.23° and translation error of 0.76 mm based on the phantom experiment), whereas the structured-light scanner had the best cost performance. The results of this study provide recommendations and precautions for researchers regarding selecting and using an appropriate device for the co-registration of on-scalp MEG and MRI.

Comparative Analysis Between the Main 3D Scanning Techniques: Photogrammetry, Terrestrial Laser Scanner, and Structured Light Scanner in Religious Imagery: The Case of The Holy Christ of the Blood

2022 ◽  
Vol 15 (1) ◽  
pp. 1-23
Author(s):  
Rafael Melendreras Ruiz ◽  
Ma Teresa Marín Torres ◽  
Paloma Sánchez Allegue
Keyword(s):  
Comparative Analysis ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Main Tool ◽  
3D Scanning ◽  
Advantages And Disadvantages ◽  
Digital Format ◽  
Structured Light Scanner ◽  
Religious Imagery

In recent years, three-dimensional (3D) scanning has become the main tool for recording, documenting, and preserving cultural heritage in the long term. It has become the “document” most in demand today by historians, curators, and art restorers to carry out their work based on a “digital twin,” that is, a totally reliable and accurate model of the object in question. Thanks to 3D scanning, we can preserve reliable models in digital format of the real state of our heritage, some of which are currently destroyed. The first step is to digitize our heritage with the highest possible quality and precision. To do this, it will be necessary to identify the most appropriate technique. In this article, we will show some of the main digitization techniques currently used in sculpture heritage and the workflows associated with them to obtain high-quality models. Finally, a complete comparative analysis will be made to show their main advantages and disadvantages.

scholarly journals Structured-light 3D scanning of exhibited historical clothing—a first-ever methodical trial and its results

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jerzy Montusiewicz ◽  
Marek Miłosz ◽  
Jacek Kęsik ◽  
Kamil Żyła
Keyword(s):  
Cultural Heritage ◽  
Information Technologies ◽  
Structured Light ◽  
Three Dimensional ◽  
3D Models ◽  
3D Scanning ◽  
Dimensional Representation ◽  
3D Scanner ◽  
Three Dimensional Representation ◽  
3D Scanners

AbstractHistorical costumes are part of cultural heritage. Unlike architectural monuments, they are very fragile, which exacerbates the problems of their protection and popularisation. A big help in this can be the digitisation of their appearance, preferably using modern techniques of three-dimensional representation (3D). The article presents the results of the search for examples and methodologies of implementing 3D scanning of exhibited historical clothes as well as the attendant problems. From a review of scientific literature it turns out that so far practically no one in the world has made any methodical attempts at scanning historical clothes using structured-light 3D scanners (SLS) and developing an appropriate methodology. The vast majority of methods for creating 3D models of clothes used photogrammetry and 3D modelling software. Therefore, an innovative approach was proposed to the problem of creating 3D models of exhibited historical clothes through their digitalisation by means of a 3D scanner using structural light technology. A proposal for the methodology of this process and concrete examples of its implementation and results are presented. The problems related to the scanning of 3D historical clothes are also described, as well as a proposal how to solve them or minimise their impact. The implementation of the methodology is presented on the example of scanning elements of the Emir of Bukhara's costume (Uzbekistan) from the end of the nineteenth century, consisting of the gown, turban and shoes. Moreover, the way of using 3D models and information technologies to popularise cultural heritage in the space of digital resources is also discussed.

Virtual skeletons: using a structured light scanner to create a 3D faunal comparative collection

2009 ◽  
Vol 36 (9) ◽  
pp. 2018-2023 ◽  
Author(s):  
Laura Niven ◽  
Teresa E. Steele ◽  
Hannes Finke ◽  
Tim Gernat ◽  
Jean-Jacques Hublin
Keyword(s):  
Structured Light ◽  
Structured Light Scanner

scholarly journals Between Hemse and Mästermyr

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Gunnar Almevik ◽  
Bertil Pärmsten ◽  
Magnus Sjöholm
Keyword(s):  
3D Printing ◽  
Structured Light ◽  
3D Scanning ◽  
Wooden Floor ◽  
Oak Wood ◽  
Research Article ◽  
Forensic Examination ◽  
Mode Of Operation ◽  
Hypothetical Question

The distance between Hemse church and the fields of Mästermyr on the Swedish Island of Gotland is about eight kilometers. The distance or rather the proximity between these two places is given importance in this filmed research article. In the 1930s, a farmer found a wooden chest in Mästermyr containing hundreds of forged tools and other artefacts. During a restoration of the Romanesque Hemse church in the 1890s, reused parts of a stave church were discovered in the wooden floor. The hypothetical question that is investigated in this study is whether the tools from Mästermyr were used in the construction of Hemse stave church in the early 1100’s? This filmed article analyzes and compares the traces of toolmarks in Hemse stave church and the woodworking tools from the Märstermyr finding. Through a forensic examination involving 3D scanning with structured light, 3D printing and reconstruction of tools and woodworking procedures, it is revealed that several toolmarks in the stave church correspond to the characteristics of woodworking tools in the Mästermyr find. The tool's shape, dimensions and mode of operation are traced in its negative imprint in the stave church’s oak wood.

scholarly journals DENSE 3D OBJECT RECONSTRUCTION USING STRUCTURED-LIGHT SCANNER AND DEEP LEARNING

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 777-783
Author(s):  
V. V. Kniaz ◽  
V. A. Mizginov ◽  
L. V. Grodzitkiy ◽  
N. A. Fomin ◽  
V. A. Knyaz
Keyword(s):  
Optical Flow ◽  
3D Model ◽  
Stereo Matching ◽  
Structured Light ◽  
Primary Source ◽  
Ground Truth ◽  
Complex Surface ◽  
Systems Model ◽  
Structured Light Scanner ◽  
Starting Point

Abstract. Structured light scanners are intensively exploited in various applications such as non-destructive quality control at an assembly line, optical metrology, and cultural heritage documentation. While more than 20 companies develop commercially available structured light scanners, structured light technology accuracy has limitations for fast systems. Model surface discrepancies often present if the texture of the object has severe changes in brightness or reflective properties of its texture. The primary source of such discrepancies is errors in the stereo matching caused by complex surface texture. These errors result in ridge-like structures on the surface of the reconstructed 3D model. This paper is focused on the development of a deep neural network LineMatchGAN for error reduction in 3D models produced by a structured light scanner. We use the pix2pix model as a starting point for our research. The aim of our LineMatchGAN is a refinement of the rough optical flow A and generation of an error-free optical flow B̂. We collected a dataset (which we term ZebraScan) consisting of 500 samples to train our LineMatchGAN model. Each sample includes image sequences (Sl, Sr), ground-truth optical flow B and a ground-truth 3D model. We evaluate our LineMatchGAN on a test split of our ZebraScan dataset that includes 50 samples. The evaluation proves that our LineMatchGAN improves the stereo matching accuracy (optical flow end point error, EPE) from 0.05 pixels to 0.01 pixels.

scholarly journals Comparisons of Electromagnetic Scattering Properties of Real Hailstones and Spheroids

2019 ◽  
Vol 58 (1) ◽  
pp. 93-112 ◽  
Author(s):  
Zhiyuan Jiang ◽  
Matthew R. Kumjian ◽  
Robert S. Schrom ◽  
Ian Giammanco ◽  
Tanya Brown-Giammanco ◽  
...  
Keyword(s):  
Electromagnetic Scattering ◽  
3D Structure ◽  
Laser Scanner ◽  
The United States ◽  
Dipole Approximation ◽  
Horizontal Polarization ◽  
Differential Phase ◽  
Irregular Shapes ◽  
Linear Depolarization Ratio ◽  
Differential Reflectivity

AbstractSevere (>2.5 cm) hail causes >$5 billion in damage annually in the United States. However, radar sizing of hail remains challenging. Typically, spheroids are used to represent hailstones in radar forward operators and to inform radar hail-sizing algorithms. However, natural hailstones can have irregular shapes and lobes; these details significantly influence the hailstone’s scattering properties. The high-resolution 3D structure of real hailstones was obtained using a laser scanner for hail collected during the 2016–17 Insurance Institute for Business and Home Safety (IBHS) Hail Field Study. Plaster casts of several record hailstones (e.g., Vivian, South Dakota, 2010) were also scanned. The S-band scattering properties of these hailstones were calculated with the discrete dipole approximation (DDA). For comparison, scattering properties of spheroidal approximations of each hailstone (with identical maximum and minimum dimensions and mass) were calculated with the T matrix. The polarimetric radar variables have errors when using spheroids, even for small hail. Spheroids generally have smaller variations in the polarimetric variables than the real hailstones. This increased variability is one reason why the correlation coefficient tends to be lower in observations than in forward-simulated cases using spheroids. Backscatter differential phase δ also is found to have large variance, particularly for large hailstones. Irregular hailstones with a thin liquid layer produce enhanced and more variable values for reflectivity factor at horizontal polarization ZHH, differential reflectivity ZDR, specific differential phase KDP, linear depolarization ratio (LDR), and δ compared with dry hailstones; is also significantly reduced.

Sign in / Sign up

Export Citation Format

Share Document