scholarly journals Visible Light Communications through Diffusive Illumination of Sculptures in a Real Museum

2021 ◽  
Vol 10 (3) ◽  
pp. 45
Author(s):  
Marco Meucci ◽  
Marco Seminara ◽  
Fabio Tarani ◽  
Cristiano Riminesi ◽  
Jacopo Catani

The recent, massive diffusion of LED-based illumination devices makes Visible Light Communications (VLC) a widely recognised wireless communication technology with large potential impact in many indoor and outdoor applications. In the indoor scenario, one of the most promising VLC implementations is foreseen in museums, exhibitions and cultural heritage sites. In this context, digital data can be transmitted by the specific lighting system of each artwork and received by the nearby standing visitors, allowing a complete set of dedicated services such as augmented reality (AR) and real-time indoor positioning, exploiting the directionality of the optical channel. In this work, we achieve, for the first time, VLC transmission through diffusive LED illumination of three-dimensional artworks (wooden and marble sculptures) in a real museum, exploiting the available LED illumination system, demonstrating the feasibility of VLC technology also when complex three-dimensional artworks, such as sculptures or bas-reliefs, are involved. In our experimental campaign, performed inside the Basilica of Santa Maria Novella in Florence, we perform extensive Packet Error Rate (PER) and Signal-to-Noise Ratio (SNR) tests on two important wooden and marble sculptures (Crucifix by Brunelleschi and the Holy Water Font by Bordoni, respectively), for different distances, view angles and configurations, in order to mimic a wide set of situations that visitors may encounter in a realistic scenario. We achieve successful VLC transmission for distances up to 8 m from artworks, at baud rate of 28 kBaud. We also provide detailed results on the characterization of the transmission Field of View (FoV) for our prototype, as well as the effect of side shifts of the observer’s position on the quality of VLC transmission, providing essential information for future implementations of positioning protocols and dedicated services in realistic, indoor scenarios. Our work represents an important step forward towards the deployment of VLC technology in museums and, more in general, it opens for far-reaching developments in a wide set of real indoor environments, including the cultural heritage sector, where diffusive VLC links exploiting illumination of three-dimensional objects could represent a ground-breaking innovation.

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.


2019 ◽  
Vol 2 (2) ◽  
pp. 150-165
Author(s):  
Damien Vurpillot ◽  
Quentin Verriez ◽  
Matthieu Thivet

High density remote survey technologies have become widespread practices. In recent years, we have seen a tenfold increase in volume of digital data acquired. Beyond this sheer amount of data, multimodal three-dimensional data exploitation has become another common challenge for specialists. The Aspectus project aims to ease the access to complex three-dimensional data and to promote collaborative work and remote expert assessment. Thus, we can get past the problem of distance and availability of the “object of expertise”, ranging from cultural heritage sites to artefacts. By extension, it enables us to circumvent the ever-present problem of destruction. Aspectus takes advantage of available open source solutions to produce a flexible web-based visualization and collaboration tool. After an overview of the theoretical framework and its technical implementation, we will discuss a practical application as part of the “Bibracte Numérique” project.


Author(s):  
Nefeli Tentoma ◽  
Andreas Georgopoulos ◽  
Gracia Tucci

The significance of preservation of cultural heritage is undeniable, which is why both their geometric documentation and the creation of their digital “twins”, i.e. reconstructions and replicas at any scale, are essential procedures. A special category of cultural heritage is sacred sites which combine historical, spiritual and religious values. The most sacred monument of Christianity is the Holy Aedicule covering the Tomb of Christ in the Church of the Holy Sepulchre in Jerusalem. This paper aims to investigate and compare the various three-dimensional representations of the Holy Aedicule of the Tomb of Christ, which exist both in physical and in digital form. Initially, the main structural phases of the Aedicule are presented, including its destructions and restorations. Moreover, the different categories of the three-dimensional representations of the monument are defined.  With reference to the replicas, both the reasons of their construction and their list in the form of a dataset table are presented. More specifically, in the context of this research, the three-dimensional representations of the Aedicule are divided into two major categories: the replicas constructed worldwide and the geometric documentations of the monument's condition through the years. Regarding the replicas, a list of the discovered representations is created and this database is visualized and depicted in an online web map along with essential information with the use of an open-source Geographic Information System (GIS). Based on this visualization an online web map has been created. Furthermore, the previous geometric documentations and surveys of the Holy Aedicule of the Tomb of Christ are presented. A comparison is conducted between the 3D models of the Aedicule, which were created by the University of Florence in 2007-8 and the National Technical University of Athens in 2015-17. The impact of the Holy Aedicule across the world is examined through statistics based on the type, date of construction and location of the replicas. The possible deformations of the monument's structure are detected from the assessment of the results from both the processing and the comparison of the 3D models. In conclusion, future works are suggested focusing on the discovery of the total number of replicas worldwide and the monitoring of the condition of the Aedicule.  Cultural


Author(s):  
Trio Adiono ◽  
Syifaul Fuada ◽  
Rosmianto Aji Saputro

<p class="0abstract">Visible Light Communication (VLC) is an emerging optical communication technology with rapid development nowadays. VLC is considered as a compliment and successor of radio-frequency (RF) wireless communication. There are various typical implementations of VLC in which one of them is for exchanging data TCP/IP packets, thus the user can browse the internet as in established Wireless fidelity (Wi-Fi) technology. Briefly, we can call it by Light fidelity (Li-Fi). This paper described the design and implementation of System-on-Chip (SoC) subsystem for Li-Fi application where the implemented SoC consists of hardware (H/W) and software (S/W). In the H/W aspect, Physical Layer (PHY) is made by using UART communication with Ethernet connection to communicate with Host/Device personal-computer (PC). In the S/W aspect, Xillinux operating system (OS) is used. The H/W- as well as S/W-SoC, are realized in FPGA Zybo Zynq-7000 EPP development board. The functional test result shows (without optical channel or Zybo-to-Zybo only) that the implemented SoC is working as expected. It is able to exchange TCP/IP packets between two PCs. Moreover, Ethernet connection has bandwidth up to 83.6 Mbps and PHY layer <em>baud rate</em> has bandwidth up to 921600 bps.</p>


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.


RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20446-20456
Author(s):  
Xi Ma ◽  
Ziwei Wang ◽  
Haoguo Yang ◽  
Yiqiu Zhang ◽  
Zizhong Zhang ◽  
...  

Compared with traditional layered graphene, graphene hydrogels have been used to construct highly efficient visible light-excited photocatalysts due to their particular three-dimensional network structure and efficient electron transport capacity.


Author(s):  
Elizabeth Eso ◽  
Petr Pesek ◽  
Petr Chvojka ◽  
Zabih Ghassemlooy ◽  
Stanislav Zvanovec ◽  
...  

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