Virtual Reality, Digital Twins, the Metaverse

Topic Information

Dear Colleagues,

With the rapid development of modern society, the demand for practicability and intelligence is increasing day by day, and more application technologies are focusing on the development of digital intelligence in the future. The intelligent development of smart manufacturing, smart industry, smart medical, and other fields is the only way to build a smart city in the future. In the future, it will even go further beyond the level of cities and countries to realize intelligent research on the entire universe and explore the origin and development of the universe from a more intelligent perspective.

Virtual reality (VR) contains a variety of information technologies, among which simulation technology has developed in a more extensive direction in recent years. The demand for virtual reality technology in various industries and fields is increasing, and chasing a more extreme sense of immersion is the mainstream of current development. Interactivity is also an important focus of research and development. In complex practical application scenarios, a stable experience is an important consideration in determining the pros and cons of practical applications. Real-time and effective interaction ideas and methods are important evaluation indicators for virtual reality technology.

Digital twin (DT) provides a broader application space for virtual reality and at the same time puts forward higher requirements for the technological progress of virtual reality. In the future, various objects in the virtual world will have more abundant intelligence, which is a necessary condition for them to be able to evolve independently and to map each other with objects in the real world. For applications that already exist and will be developed in the future, the integration of real-world data into the virtual world is critical to the development of digital twin technology. New sensors play a vital role in this, and this will also be the key to whether the digital twin can better develop in coordination with multiple fields.

The exhibition of a variety of virtual achievements indicates that the development of the metaverse is no longer limited to the conceptual level, and the digital twin provides a fundamentally effective way for it. The development of VR, DT, and the Metaverse promote each other, forming a closed-loop mutual push development method. This Topic involves a wide range of multidisciplinary themes and realizes more systematic intelligent and digital development in multiple fields, such as industry, manufacturing, education, aerospace, medical and health, and urban development.

Dr. Zhihan Lv
Prof. Dr. Kai Xu
Prof. Dr. Zhigeng Pan
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.7	4.5	2011	16.9 Days	CHF 2400
Electronics electronics	2.9	4.7	2012	15.6 Days	CHF 2400
Healthcare healthcare	2.8	2.7	2013	19.5 Days	CHF 2700
Sensors sensors	3.9	6.8	2001	17 Days	CHF 2600
Sustainability sustainability	3.9	5.8	2009	18.8 Days	CHF 2400

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Published Papers (34 papers)

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24 pages, 24412 KiB  

Open AccessArticle

Virtual Reality as a Tool for Sustainable Training and Education of Employees in Industrial Enterprises

by Věroslav Holuša, Michal Vaněk, Filip Beneš, Jiří Švub and Pavel Staša

Sustainability 2023, 15(17), 12886; https://doi.org/10.3390/su151712886 - 25 Aug 2023

Cited by 3 | Viewed by 2845

Abstract

The paper deals with the possibilities of using Virtual Reality in the training and safety of enterprises active in the raw materials industry. It examines the influence and impact on their employees. The main impetus for starting research in this area has been [...] Read more.

The paper deals with the possibilities of using Virtual Reality in the training and safety of enterprises active in the raw materials industry. It examines the influence and impact on their employees. The main impetus for starting research in this area has been a need for more use of the full potential of Virtual Reality in the industrial sector. Virtual Reality (VR) has become a promising education and employee training tool. It provides an immersive and interactive learning environment, allowing users to engage with simulations, scenarios, and simulations in real time. VR can facilitate the acquisition of practical skills, help learners retain information better, and foster the development of soft skills, such as communication, teamwork, and leadership. The paper is divided into the following sections. The first two are devoted to the introduction to the issue and a review of the literature. The materials and methods section describes the possibilities of using photogrammetry to create virtual scenes and 3D models usable in Virtual Reality. This section also describes the research methods used to evaluate the approach for teaching and training employees. The last two sections evaluate and discuss the results achieved. Having regarded the research realized, it was found that our approach to researching the education of employees and the development of their skills brings excellent benefits and, compared to the traditional educational approach, is much more time-efficient so that employees can improve their work habits and behavior in a relatively short period. In employee training, VR can simulate real-life scenarios, providing workers with hands-on experience in a safe, controlled environment. This technology can also help companies save time and resources, eliminating the need for travel and reducing expenditure on expensive equipment. However, despite its many benefits, VR in education and training can be cost-demanding and requires specialized hardware and software, which may limit its widespread adoption. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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20 pages, 2974 KiB  

Open AccessArticle

Environmental Sustainability of Metaverse: Perspectives from Romanian Developers

by Ștefan Vlăduțescu and Georgiana Camelia Stănescu

Sustainability 2023, 15(15), 11704; https://doi.org/10.3390/su151511704 - 28 Jul 2023

Cited by 4 | Viewed by 1389

Abstract

The metaverse is currently in the process of development and has applications in various fields, ranging from the gaming industry to art, communication, education, and fashion. Researchers regard the metaverse as the future of the internet, and, in this context, the impact of [...] Read more.

The metaverse is currently in the process of development and has applications in various fields, ranging from the gaming industry to art, communication, education, and fashion. Researchers regard the metaverse as the future of the internet, and, in this context, the impact of this new universe’s development on the environment needs to be investigated to find viable solutions for its sustainability. We have discussed the economic and social sustainability consequences of the metaverse, and we have largely concentrated on the environmental effects. In conducting this research, we used a quantitative methodology mainly based on a structured questionnaire. We analyzed the impact of the metaverse on the environment from the perspective of professionals in the Romanian software development and programming industries. We selected this sample because the field is newly emerging and because they are experts on how the metaverse functions and evolves. We concluded that IT professionals believe that the new universe could have several negative impacts on the natural environment, such as increased power consumption or increased CO₂. emissions and the negative impact can be mitigated by adopting clear regulations and sustainable policies at the international level. This study aims to contribute to the long-term sustainability of the metaverse ecosystem by facilitating a comprehensive understanding of its functioning and evolution, as well as by addressing potential negative impacts on the natural environment. Additionally, the study seeks to make a scholarly contribution to advancing a sustainable metaverse by fostering informed decision-making processes and encouraging responsible practices within the industry. This research might be useful for technology companies, academics, and policymakers. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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20 pages, 5263 KiB  

Open AccessArticle

Wear Prediction of Curved Switch Rail in High-Speed Turnout and Influence of Wheel and Rail Wear on Vehicle Dynamic Performance

by Shuo Yan, Taotao Jin, He Ma, Jun Zhang and Yi Zhou

Appl. Sci. 2023, 13(14), 8398; https://doi.org/10.3390/app13148398 - 20 Jul 2023

Viewed by 812

Abstract

A wear prediction model is built to research the wear of the curved switch rail in a high-speed turnout. The Archard wear model is used in the wear prediction model to analyze the profile evolution law. The non-Hertzian contact Kik–Piotrowski method based on [...] Read more.

A wear prediction model is built to research the wear of the curved switch rail in a high-speed turnout. The Archard wear model is used in the wear prediction model to analyze the profile evolution law. The non-Hertzian contact Kik–Piotrowski method based on virtual penetration is used as the contact algorithm for the Archard wear model. A dynamic model of the vehicle–curved switch rail system based on the predicted profiles of the curved switch rail and the measured wheel profiles with different stages is established. The effect of the wheel and curved switch rail profiles’ wear on vehicle dynamic performance is analyzed. The results show that the wheel completely transitions from the stock rail to the curved switch rail between 35 and 50 mm head widths. As the head width of the curved switch rail increased, the position of the maximum wear depth gradually moved to the gauge shoulder. When the total passing weight of the train is 50 Mt, the 20 mm head width curved switch rail side wear reaches a maximum of 5.3 mm. The position in which the wheel transitions from the stock rail to the curved switch rail will be further away from the tip of the curved switch rail due to wheel–rail wear. Regarding the derailment coefficient, the wheel–rail vertical force and lateral force are both significantly impacted. However, they have little effect on the vertical and lateral acceleration of the vehicle. The wear of the wheels and rails has a higher impact on vehicle driving safety and a lower impact on vehicle driving stability. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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13 pages, 1313 KiB  

Open AccessArticle

An Exploratory Study about the Effect of COVID-19 on the Intention to Adopt Virtual Reality in the Tourism Sector

by Nuno Sousa, Filipa Jorge, Mário Sérgio Teixeira, Nieves Losada, Miguel Melo and Maximino Bessa

Sustainability 2023, 15(11), 8725; https://doi.org/10.3390/su15118725 - 29 May 2023

Cited by 9 | Viewed by 1548

Abstract

During the health crisis caused by COVID-19, virtual reality (VR) proved to be useful for the tourism industry, allowing this industry to continue working despite the restrictions imposed. However, it remains to be seen if the impact of this sanitary crisis in the [...] Read more.

During the health crisis caused by COVID-19, virtual reality (VR) proved to be useful for the tourism industry, allowing this industry to continue working despite the restrictions imposed. However, it remains to be seen if the impact of this sanitary crisis in the tourism industry influenced managers’ intention to adopt this technology in the post-pandemic period. To fill this gap, a qualitative methodological approach was adopted, using the MAXQDA20 software and interviews with managers of tourism enterprises. The results show that the willingness to invest in technology, the perception of VR as a business strategy, and the perception of the impact of the pandemic are factors that regulate the intention of companies to adopt VR. In addition, prior experience with VR and the perception of technical support are also important for its adoption. Thus, it was concluded that VR can be a valuable sustainable strategy for tourism companies to address the challenges imposed by the pandemic. However, adopting the technology depends on factors such as financial availability, business strategy, and previous experience with VR. Furthermore, tourism companies must also receive adequate technical support to ensure its correct implementation. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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16 pages, 4918 KiB  

Open AccessArticle

Design and Application of Logical Range Framework Based on Digital Twin

by Hao Chen, Zheng Dang, Xinhong Hei and Kai Wang

Appl. Sci. 2023, 13(11), 6589; https://doi.org/10.3390/app13116589 - 29 May 2023

Cited by 1 | Viewed by 1088

Abstract

With the development of the concept of integrated flight testing, joint testing has become a key research trend. The use of a Logical Range can allow one to overcome the shortcomings of traditional test ranges, allowing for full use of the resources of [...] Read more.

With the development of the concept of integrated flight testing, joint testing has become a key research trend. The use of a Logical Range can allow one to overcome the shortcomings of traditional test ranges, allowing for full use of the resources of each range when implementing joint flight testing. However, the Logical Range concept also has problems, such as those relating to the low reusability of test resources and insufficient ability to monitor the resource status in real-time. Considering such problems, a Logical Range framework based on digital twin technology is proposed in this paper. On the basis of this framework, a Logical Range system based on a digital twin for the real-time mapping of real physical behavior is constructed and the three key technologies used in the system are detailed. The feasibility of the framework is successfully verified through a flight test, demonstrating that the proposed framework can provide key support for the application of digital twin technology in the field of flight testing. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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23 pages, 4534 KiB  

Open AccessArticle

VanityX: An Agile 3D Rendering Platform Supporting Mixed Reality

by Ivan Zoraja, Mirjana Bonkovic, Vladan Papic and Vaidy Sunderam

Appl. Sci. 2023, 13(9), 5468; https://doi.org/10.3390/app13095468 - 27 Apr 2023

Viewed by 2329

Abstract

VanityX is a prototype, low-level, real-time 3D rendering and computing platform. Unlike most XR solutions, which integrate several commercial and/or open-source products, such as game engines, XR libraries, runtime, and services, VanityX is a platform ready to adapt to any business domain including [...] Read more.

VanityX is a prototype, low-level, real-time 3D rendering and computing platform. Unlike most XR solutions, which integrate several commercial and/or open-source products, such as game engines, XR libraries, runtime, and services, VanityX is a platform ready to adapt to any business domain including anthropology and medicine. The design, architecture, and implementation are presented, which are based on CPU and GPU asymmetric multiprocessing with explicit synchronization and collaboration of parallel tasks and a predictable transfer of pipeline resources between processors. The VanityX API is based on DirectX 12 and native programming languages C++20 and HLSL 6, which, in conjunction with explicit parallel processing, the asynchronous loading and explicit managing of graphic resources, and effective algorithms, results in great performance and resource utilization close to metal. Surface-based rendering, direct volume rendering (DVR), and mixed reality (MR) on the HoloLens 2 immersive headset are currently supported. Our MR applications are directly compiled and deployed to HoloLens 2 allowing for better programming experiences and software engineering practices such as testing, debugging, and profiling. The VanityX server provides various computational and rendering services to its clients running on HoloLens 2. The use and test cases are in many business domains including anthropology and medicine. Our future research challenges will primarily, via the MetaverseMed project, focus on opening new opportunities for implementing innovative MR-based scenarios in medical procedures, especially in education, diagnostics, and surgical operations. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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20 pages, 15639 KiB  

Open AccessArticle

Viewpoint-Controllable Telepresence: A Robotic-Arm-Based Mixed-Reality Telecollaboration System

by Le Luo, Dongdong Weng, Jie Hao, Ziqi Tu and Haiyan Jiang

Sensors 2023, 23(8), 4113; https://doi.org/10.3390/s23084113 - 19 Apr 2023

Cited by 1 | Viewed by 1724

Abstract

In mixed-reality (MR) telecollaboration, the local environment is remotely presented to a remote user wearing a virtual reality (VR) head-mounted display (HMD) via a video capture device. However, remote users frequently face challenges in naturally and actively manipulating their viewpoints. In this paper, [...] Read more.

In mixed-reality (MR) telecollaboration, the local environment is remotely presented to a remote user wearing a virtual reality (VR) head-mounted display (HMD) via a video capture device. However, remote users frequently face challenges in naturally and actively manipulating their viewpoints. In this paper, we propose a telepresence system with viewpoint control, which involves a robotic arm equipped with a stereo camera in the local environment. This system enables remote users to actively and flexibly observe the local environment by moving their heads to manipulate the robotic arm. Additionally, to solve the problem of the limited field of view of the stereo camera and limited movement range of the robotic arm, we propose a 3D reconstruction method combined with a stereo video field-of-view enhancement technique to guide remote users to move within the movement range of the robotic arm and provide them with a larger range of local environment perception. Finally, a mixed-reality telecollaboration prototype was built, and two user studies were conducted to evaluate the overall system. User study A evaluated the interaction efficiency, system usability, workload, copresence, and user satisfaction of our system from the remote user’s perspective, and the results showed that our system can effectively improve the interaction efficiency while achieving a better user experience than two traditional view-sharing techniques based on 360 video and based on the local user’s first-person view. User study B evaluated our MR telecollaboration system prototype from both the remote-user side and the local-user side as a whole, providing directions and suggestions for the subsequent design and improvement of our mixed-reality telecollaboration system. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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14 pages, 620 KiB  

Open AccessArticle

Effectiveness of the Patient’s Severity Classification Competency Promotion Virtual Reality Program of Nursing Students during the COVID-19 Pandemic Period

by Eunju Lee, Gyuli Baek and Yeonhui Hwang

Healthcare 2023, 11(8), 1122; https://doi.org/10.3390/healthcare11081122 - 13 Apr 2023

Viewed by 1248

Abstract

The purpose of this study was to develop a virtual reality-based nursing education program aimed at improving nursing students’ severity classification competency. Severity classification in the emergency room is key to improving the efficiency of emergency room services worldwide. Prioritizing treatment based on [...] Read more.

The purpose of this study was to develop a virtual reality-based nursing education program aimed at improving nursing students’ severity classification competency. Severity classification in the emergency room is key to improving the efficiency of emergency room services worldwide. Prioritizing treatment based on correctly identifying the severity of a disease or an injury also ensures patients’ safety. The five actual clinical scenarios in the program helped to promptly classify patients into five clinical situations based on the 2021 Korean Emergency Patient Classification Tool. Seventeen nursing students were in an experimental group that had access to a virtual reality-based simulation combined with clinical practice. Seventeen nursing students were in a control group that only participated in routine clinical practice. The virtual reality-based nursing education program effectively improved students’ severity classification competency, performance confidence, and clinical decision-making ability. Although the pandemic continues, the virtual reality-based nursing education program provides realistic indirect experiences to nursing students in situations where clinical nursing practice is not possible. In particular, it will serve as basic data for the expansion and utilization strategy of virtual reality-based nursing education programs to improve nursing capabilities. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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17 pages, 8396 KiB  

Open AccessArticle

Prediction System for Overhead Cranes Based on Digital Twin Technology

by Pei Gao, Zongyan Wang, Yuting Zhang and Menglong Li

Appl. Sci. 2023, 13(8), 4696; https://doi.org/10.3390/app13084696 - 7 Apr 2023

Cited by 3 | Viewed by 2129

Abstract

To solve the problems of inaccurate quality inspection and poor safety maintenance of traditional overhead cranes, this study has developed a prediction system for overhead cranes based on digital twin technology. First, interworking of the data flow between the control port of the [...] Read more.

To solve the problems of inaccurate quality inspection and poor safety maintenance of traditional overhead cranes, this study has developed a prediction system for overhead cranes based on digital twin technology. First, interworking of the data flow between the control port of the overhead crane and the digital twin system is realized. Then, finite element technology is exploited to calculate the stress of the crane bridge, thereby performing stress rendering of the digital twin system. Next, the life of bridge cranes is predicted by the stress and strain of their main girders. Finally, synchronous overhead-crane communication combines the virtual twin system and the actual control system of the crane. The study results provide a reference for developing crane software based on digital twins. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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26 pages, 12961 KiB  

Open AccessArticle

Multi-Robot Collaborative Flexible Manufacturing and Digital Twin System Design of Circuit Breakers

by Linghao Wang, Liang Shu and Hao Zhou

Appl. Sci. 2023, 13(4), 2721; https://doi.org/10.3390/app13042721 - 20 Feb 2023

Cited by 1 | Viewed by 2620

Abstract

Circuit breakers (CBs) are mainly designed to interrupt current flow when faults are detected and have been widely used in industrial applications. The existing CBs manufacturing method is semi-automatic and requires a lot of labor. To realize flexible manufacturing, a multi-robot cooperative CBs [...] Read more.

Circuit breakers (CBs) are mainly designed to interrupt current flow when faults are detected and have been widely used in industrial applications. The existing CBs manufacturing method is semi-automatic and requires a lot of labor. To realize flexible manufacturing, a multi-robot cooperative CBs flexible manufacturing system (CBFMS) is presented in this study. Aiming at the efficiency of the multi-robot cooperative CBFMS key units, a two-arm cooperation robot approach is proposed. The reinforcement learning algorithm is developed to optimize the manufacturing trajectory of the two-arm cooperation robot. To build and optimize the multi-robot cooperative CBFMS, a digital twin (DT) system describing all physical properties of the physical manufacturing plant is constructed for simulation. In the developed DT system, a kinematic control model of the collaboration robot is established. A real-time display of the robot’s trajectory, manufacturing status, and process manufacturing is provided by the data interaction with the physical cell flow between the units. Following this design, a synchronous mapping between the flexible manufacturing DT system of the CBs and the physical workshop is realized, which enables real-time monitoring and management of the physical production line. The experiments’ results show that the manufacturing efficiency, compared with traditional CBs production, is improved by 22%. Moreover, the multi-robot cooperative CBFMS can make process changes according to the production requirements, which can improve the stability of production. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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13 pages, 757 KiB  

Open AccessArticle

Weight Illusion Caused by Sinusoidal Vibration Correlates with Grip Force Adjustment

by Giryeon Kim, Shogo Okamoto and Hisataka Maruyama

Appl. Sci. 2023, 13(4), 2717; https://doi.org/10.3390/app13042717 - 20 Feb 2023

Viewed by 1387

Abstract

Our research team previously identified a weight illusion in which a lifted object feels heavy when it continuously presents a sinusoidal vibration to the fingertips. However, the mechanism underlying this illusion remains unknown. We thus hypothesized that the autonomous grip force adjustment against [...] Read more.

Our research team previously identified a weight illusion in which a lifted object feels heavy when it continuously presents a sinusoidal vibration to the fingertips. However, the mechanism underlying this illusion remains unknown. We thus hypothesized that the autonomous grip force adjustment against a vibrating object would be one of the factors underlying the weight illusion. The autonomous grip force adjustment increases the motor outputs of a human hand system, subsequently raising the sense of effort to keep holding the lifted object. The grip forces and perceived heaviness were evaluated using vibratory stimuli with five different frequencies (30 Hz, 60 Hz, 100 Hz, 200 Hz, and 300 Hz) and three different amplitudes (156 $\mathsf{\mu }$m, 177 $\mathsf{\mu }$m, and 203 $\mathsf{\mu }$m). The results showed that the stimuli at lower frequencies or large amplitudes increased the grip forces more and felt heavier than the stimuli at higher frequencies or small amplitudes. Specifically, the 30 Hz stimuli felt the heaviest and increased the grip force the most. An increase in the grip force was positively correlated with the perceived heaviness. These results indicate that vibratory stimuli influence both the grip force and weight perception. Our findings can contribute to developing haptic displays to present virtual heaviness. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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28 pages, 2092 KiB  

Open AccessReview

Digital Twins and Enabling Technologies in Museums and Cultural Heritage: An Overview

by Wolfram Luther, Nelson Baloian, Daniel Biella and Daniel Sacher

Sensors 2023, 23(3), 1583; https://doi.org/10.3390/s23031583 - 1 Feb 2023

Cited by 16 | Viewed by 4616

Abstract

This paper presents an overview of various types of virtual museums (ViM) as native artifacts or as digital twins (DT) of physical museums (PM). Depending on their mission and features, we discuss various enabling technologies and sensor equipment with their specific requirements and [...] Read more.

This paper presents an overview of various types of virtual museums (ViM) as native artifacts or as digital twins (DT) of physical museums (PM). Depending on their mission and features, we discuss various enabling technologies and sensor equipment with their specific requirements and complexities, advantages and drawbacks in relation to each other at all stages of a DT’s life cycle. A DT is a virtual construct and embodies innovative concepts based on emerging technologies (ET) using adequate sensor configurations for (meta-)data import and exchange. Our keyword-based search for articles, conference papers, (chapters from) books and reviews yielded 43 contributions and 43 further important references from Industry 4.0, Tourism and Heritage 4.0. After closer examination, a reference corpus of 40 contributions was evaluated in detail and classified along with their variants of DT—content-, communication-, and collaboration-centric and risk-informed ViMs. Their system features correlate with different application areas (AA), new or improved technologies—mostly still under development—and sensors used. Our proposal suggests a template-based, generative approach to DTs using standardized metadata formats, expert/curator software and customers’/visitors’ engagement. It advocates for stakeholders’ collaboration as part of a comprehensive validation and verification assessment (V&VA) throughout the DT’s entire life cycle. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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16 pages, 973 KiB  

Open AccessReview

Study on the Applicability of Digital Twins for Home Remote Motor Rehabilitation

by Piotr Falkowski, Tomasz Osiak, Julia Wilk, Norbert Prokopiuk, Bazyli Leczkowski, Zbigniew Pilat and Cezary Rzymkowski

Sensors 2023, 23(2), 911; https://doi.org/10.3390/s23020911 - 12 Jan 2023

Cited by 6 | Viewed by 2876

Abstract

The COVID-19 pandemic created the need for telerehabilitation development, while Industry 4.0 brought the key technology. As motor therapy often requires the physical support of a patient’s motion, combining robot-aided workouts with remote control is a promising solution. This may be realised with [...] Read more.

The COVID-19 pandemic created the need for telerehabilitation development, while Industry 4.0 brought the key technology. As motor therapy often requires the physical support of a patient’s motion, combining robot-aided workouts with remote control is a promising solution. This may be realised with the use of the device’s digital twin, so as to give it an immersive operation. This paper presents an extensive overview of this technology’s applications within the fields of industry and health. It is followed by the in-depth analysis of needs in rehabilitation based on questionnaire research and bibliography review. As a result of these sections, the original concept of controlling a rehabilitation exoskeleton via its digital twin in the virtual reality is presented. The idea is assessed in terms of benefits and significant challenges regarding its application in real life. The presented aspects prove that it may be potentially used for manual remote kinesiotherapy, combined with the safety systems predicting potentially harmful situations. The concept is universally applicable to rehabilitation robots. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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13 pages, 2577 KiB  

Open AccessStudy Protocol

A Study Protocol to Evaluate the Effects of Vestibular Training on the Postural Control of Healthy Adults Using Virtual Reality

by Kwadwo O. Appiah-Kubi, Evan Laing and Masudul H. Imtiaz

Appl. Sci. 2022, 12(23), 11937; https://doi.org/10.3390/app122311937 - 23 Nov 2022

Viewed by 1386

Abstract

Postural instability is a common symptom of vestibular dysfunction due to an insult to the vestibular system. Vestibular rehabilitation is effective in decreasing dizziness and visual symptoms, and improving postural control through several mechanisms, including sensory reweighting. As part of the sensory reweighting [...] Read more.

Postural instability is a common symptom of vestibular dysfunction due to an insult to the vestibular system. Vestibular rehabilitation is effective in decreasing dizziness and visual symptoms, and improving postural control through several mechanisms, including sensory reweighting. As part of the sensory reweighting mechanisms, vestibular activation training with headshake activities influences vestibular reflexes. However, combining challenging vestibular and postural tasks to facilitate more effective rehabilitation outcomes is underutilized. Our research goal is to develop a virtual reality vestibular rehabilitation method for vestibular-postural control in neurological populations with vestibular and/or sensorimotor control impairment. The NeuroCom^® SMART Balance Master (Natus Medical Inc., Pleasanton, CA, USA), which was used in a prior study, is expensive and bulky. Hence, a novel study protocol is established in this paper with the detailed objectives and pre-/post-intervention data analysis pipeline (ANOVA, t-test, post hoc analysis, etc.) involving modern off-the-shelf sensors and custom instrumentation (electromyography, electrooculography, video head impulse testing, force plates, and virtual reality headsets). It is expected that the training will significantly decrease vestibuloocular reflex gains and eye movement variability, as well as reweight the somatosensory ratio, finetune postural muscle activation, and consequently improve postural flexibility and produce a faster automatic postural response. The findings may have implications for the future development of vestibular rehabilitation protocols. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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22 pages, 6698 KiB  

Open AccessArticle

User Performance in Virtual Reality Environments: The Capability of Immersive Virtual Reality Systems in Enhancing User Spatial Awareness and Producing Consistent Design Results

by Sahand Azarby and Arthur Rice

Sustainability 2022, 14(21), 14129; https://doi.org/10.3390/su142114129 - 29 Oct 2022

Cited by 4 | Viewed by 2338

Abstract

Spatial decision-making in different virtual environments may vary based on the levels of spatial awareness experienced within Virtual Reality (VR) systems. Features and characteristics of VR systems may act as facilitators or distractors of spatial awareness, which can result in extreme variations in [...] Read more.

Spatial decision-making in different virtual environments may vary based on the levels of spatial awareness experienced within Virtual Reality (VR) systems. Features and characteristics of VR systems may act as facilitators or distractors of spatial awareness, which can result in extreme variations in user spatial decisions. This research explored the capability of an Immersive Virtual Reality Interactive Environment (IVRIE) and a desktop-based VR (DT system) in reducing extreme variations in spatial decisions and inconsistent design results. Users’ spatial decisions, performance, and design results in both systems were studied regarding the impact of these two systems’ features on users, including the sense of immersion, types of interaction, and usage of eye-level view in spatial designs. The design results produced in both systems were compared considering the types of enclosure, surface texture, scale, and spatial function. Descriptive and inferential statistical comparisons and testing using quantitative and qualitative data were applied to determine participants’ performance regarding the production of spatial outliers in each system. The results showed that IVRIE was more effective than the DT system fostering a consistency of space sizes and reducing outliers. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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12 pages, 9054 KiB  

Open AccessArticle

Real-Time Foreign Object and Production Status Detection of Tobacco Cabinets Based on Deep Learning

by Chengyuan Wang, Junli Zhao, Zengchen Yu, Shuxuan Xie, Xiaofei Ji and Zhibo Wan

Appl. Sci. 2022, 12(20), 10347; https://doi.org/10.3390/app122010347 - 14 Oct 2022

Cited by 2 | Viewed by 1344

Abstract

Visual inspection plays an important role in industrial production and can detect product defects at the production stage to avoid major economic losses. Most factories mainly rely on manual inspection, resulting in low inspection efficiency, high costs, and potential safety hazards. A real-time [...] Read more.

Visual inspection plays an important role in industrial production and can detect product defects at the production stage to avoid major economic losses. Most factories mainly rely on manual inspection, resulting in low inspection efficiency, high costs, and potential safety hazards. A real-time production status and foreign object detection framework for smoke cabinets based on deep learning is proposed in this paper. Firstly, the tobacco cabinet is tested for foreign objects based on the YOLOX, and if there is a foreign object, all production activities will be immediately stopped to avoid safety and quality problems. Secondly, the production status of tobacco cabinet is judged to determine whether it is in the feeding state by the YOLOX position locating method and canny threshold method. If it is not in the feeding state, then the three states of empty, full, and material status of the tobacco cabinet conveyor belt are judged based on the ResNet-18 image classification network. Ultilizing our proposed method, the accuracy of foreign object detection, feeding state detection and the conveyor belt of tobacco cabinet state detection are 99.13%, 96.36% and 95.30%, respectively. The overall detection time was less than 1 s. The experimental results show the effectiveness of our method. It has important practical significance for the safety, well-being and efficient production of cigarette factories. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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16 pages, 4569 KiB  

Open AccessArticle

Septoplasty Effect on the Enhancement of Airflow Distribution and Particle Deposition in Nasal Cavity: A Numerical Study

by Feng Tao, Yu Feng, Baobin Sun, Jianwei Wang, Xiaole Chen and Jiarui Gong

Healthcare 2022, 10(9), 1702; https://doi.org/10.3390/healthcare10091702 - 5 Sep 2022

Cited by 4 | Viewed by 3554

Abstract

The surgery outcomes after fixing nasal airway obstruction (NAO) are sometimes not satisfactory in improving ventilations of airflow. A case study is presented in this paper with computational fluid dynamics applied to determine the key factors for successful septoplasty plans for a patient [...] Read more.

The surgery outcomes after fixing nasal airway obstruction (NAO) are sometimes not satisfactory in improving ventilations of airflow. A case study is presented in this paper with computational fluid dynamics applied to determine the key factors for successful septoplasty plans for a patient with a deviated nasal septum. Specifically, airflow, as well as particle transport and deposition were predicted in a pre-surgery nasal cavity model reconstructed from patient-specific Computer Tomography (CT) images and two post-surgery nasal cavity models (i.e., VS1 and VS2) with different virtual surgery plans A and B. Plan A corrected the deviated septal cartilage, the perpendicular plate of the ethmoid bone, vomer, and nasal crest of the maxilla. Plan B further corrected the obstruction in the nasal vestibule and caudal nasal septal deviation based on Plan A. Simulations were performed in the three nose-to-throat airway models to compare the airflow velocity distributions and local particle depositions. Numerical results indicate that the VS2 model has a better improvement in airflow allocation between the two sides than the VS1 model. In addition, the deposition fractions in the VS2 model are lower than that in both the original and VS1 models, up to 25.32%. The better surgical plan (i.e., Plan B) reduces the particle deposition on the convex side, but slightly increases the deposition on the concave side. However, the overall deposition in the nasal cavity is reduced. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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25 pages, 8862 KiB  

Open AccessArticle

Design of a Digital Twin Training Centre for an Industrial Robot Arm

by Timotei István Erdei, Rudolf Krakó and Géza Husi

Appl. Sci. 2022, 12(17), 8862; https://doi.org/10.3390/app12178862 - 3 Sep 2022

Cited by 12 | Viewed by 4268

Abstract

The Cyber-Physical and Intelligent Robotics Laboratory has been digitally recreated, and it includes all the key elements that allow 6-axis industrial robots to perform PTP, LIN, and CIRC motions. Furthermore, the user can create a program with these motion types. The human–machine interface [...] Read more.

The Cyber-Physical and Intelligent Robotics Laboratory has been digitally recreated, and it includes all the key elements that allow 6-axis industrial robots to perform PTP, LIN, and CIRC motions. Furthermore, the user can create a program with these motion types. The human–machine interface is also integrated into our system. It can also assist SMEs in developing their in-house training. After all, training on an industrial robot unit does not entail installation costs within the facility. Nor are there any maintenance and servicing costs. Since the lab is digital, additional robot units can be added or removed. Thus, areas for training or production can be pre-configured within each facility. Because of the customizability and virtual education format, there is no room capacity problem, and trainees can participate in the exercises in parallel. Exercises were also conducted to evaluate the program’s impact on teaching, and the results showed that using machine units can improve teaching. Even today’s digital labs cannot physically convey the sense of space or the relative weights of different elements in virtual space. Even with these features, individuals can operate a machine more effectively than relying solely on traditional, non-interactive demonstration materials. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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15 pages, 4148 KiB  

Open AccessArticle

Adaptive Points Sampling for Implicit Field Reconstruction of Industrial Digital Twin

by Jiongchao Jin, Huanqiang Xu and Biao Leng

Sensors 2022, 22(17), 6630; https://doi.org/10.3390/s22176630 - 2 Sep 2022

Cited by 9 | Viewed by 1744

Abstract

Nowadays, the digital twin (DT) plays an important role in Industry 4.0. It aims to model reality in the digital space for further industrial maintenance, management, and optimization. Previously, many AI technologies have been applied in this field and provide strong tools to [...] Read more.

Nowadays, the digital twin (DT) plays an important role in Industry 4.0. It aims to model reality in the digital space for further industrial maintenance, management, and optimization. Previously, many AI technologies have been applied in this field and provide strong tools to connect physical and virtual spaces. However, we found that single-view 3D reconstruction (SVR) for DT has not been thoroughly studied. SVR can generate 3D digital models of real industrial products from just a single image. The application of SVR technology would bring convenience, cheapness, and robustness to modeling physical objects in digital space. However, the existing SVR methods cannot perform well in the reconstruction of details, which is indispensable and challenging in industrial products. In this paper, we propose a new detail-aware feature extraction network based on a feature pyramid network (FPN) for better detail reconstruction. Then, an extra network is designed to combine convolutional feature maps from different levels. Moreover, we also propose a novel adaptive points-sampling strategy to adaptively change the learning difficulty according to the training status. This can accelerate the training process and improve the fine-tuned network performance as well. Finally, we conduct comprehensive experiments on both the general objects dataset ShapeNet and a collected industrial dataset to prove the effectiveness of our methods and the practicability of the SVR technology for DT. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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24 pages, 10220 KiB  

Open AccessArticle

WUAD (Wheelchair User Assisted Design): A VR-Based Strategy to Make Buildings More Accessible

by Emiliano Pérez, Alejandro Espacio, Santiago Salamanca and Pilar Merchán

Appl. Sci. 2022, 12(17), 8486; https://doi.org/10.3390/app12178486 - 25 Aug 2022

Cited by 1 | Viewed by 1898

Abstract

Accessibility regulations towards building design and public places are more restrictive than in past years. Along with energy efficiency, accessibility is one of the pillars of an optimal building design. However, even buildings adapted for actual regulations are not always optimal, and there [...] Read more.

Accessibility regulations towards building design and public places are more restrictive than in past years. Along with energy efficiency, accessibility is one of the pillars of an optimal building design. However, even buildings adapted for actual regulations are not always optimal, and there is still much to do to avoid adding more difficulties for people with disabilities. We proposed a wheelchair-user-assisted design methodology based on iterative bidirectional communication between a wheelchair simulator user and the building designer to reach the optimum specifications for an accessibility-friendly design. First-hand experience may be crucial to detect obstacles hardly noticeable to people with no impairments. To this end, VR technology was employed along with the mentioned wheelchair simulator to show the advantages of this kind of device when working on real-life experiences. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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24 pages, 1922 KiB  

Open AccessArticle

Understanding the Effects of Virtual Reality System Usage on Spatial Perception: The Potential Impacts of Immersive Virtual Reality on Spatial Design Decisions

by Sahand Azarby and Arthur Rice

Sustainability 2022, 14(16), 10326; https://doi.org/10.3390/su141610326 - 19 Aug 2022

Cited by 17 | Viewed by 5682

Abstract

The main component of any Virtual Reality (VR) system is the human user. The ways in which a VR system shapes human experience can affect design outcomes. This research explores the differences in spatial perception between an immersive Virtual Reality Interactive Environment (IVRIE) [...] Read more.

The main component of any Virtual Reality (VR) system is the human user. The ways in which a VR system shapes human experience can affect design outcomes. This research explores the differences in spatial perception between an immersive Virtual Reality Interactive Environment (IVRIE) and traditional Virtual Reality (also known as a desktop-based Virtual Reality system, abbreviated herein as the DT system). Spatial perception and the cognition of the spatial factors of virtual spaces were studied based on different features of the two systems, including the sense of immersion, forms of interaction, experience of human scale, and movement through virtual spaces. This study focused on determining how users’ spatial decision making and performance were affected by differences in spatial perception created by the IVRIE and DT systems. Factors examined included the differences between and within the two virtual systems, based on differences in texture, system usage sequence, and the complexity of the experiential/spatial guidelines. Descriptive and inferential statistical testing using quantitative and qualitative data were used to find differences in spatial perception and decision making. The results showed significant space size variations produced by participants between and within the two different VR systems. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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18 pages, 4044 KiB  

Open AccessArticle

Effect of Visually Induced Motion Sickness from Head-Mounted Display on Cardiac Activity

by Sangin Park, Jihyeon Ha and Laehyun Kim

Sensors 2022, 22(16), 6213; https://doi.org/10.3390/s22166213 - 18 Aug 2022

Cited by 4 | Viewed by 2390

Abstract

Head-mounted display (HMD) virtual reality devices can facilitate positive experiences such as co-presence and deep immersion; however, motion sickness (MS) due to these experiences hinders the development of the VR industry. This paper proposes a method for assessing MS caused by watching VR [...] Read more.

Head-mounted display (HMD) virtual reality devices can facilitate positive experiences such as co-presence and deep immersion; however, motion sickness (MS) due to these experiences hinders the development of the VR industry. This paper proposes a method for assessing MS caused by watching VR content on an HMD using cardiac features. Twenty-eight undergraduate volunteers participated in the experiment by watching VR content on a 2D screen and HMD for 12 min each, and their electrocardiogram signals were measured. Cardiac features were statistically analyzed using analysis of covariance (ANCOVA). The proposed model for classifying MS was implemented in various classifiers using significant cardiac features. The results of ANCOVA reveal a significant difference between 2D and VR viewing conditions, and the correlation coefficients between the subjective ratings and cardiac features have significant results in the range of −0.377 to −0.711 (for SDNN, pNN50, and ln HF) and 0.653 to 0.677 (for ln VLF and ln VLF/ln HF ratio). Among the MS classification models, the linear support vector machine achieves the highest average accuracy of 91.1% (10-fold cross validation) and has a significant permutation test outcome. The proposed method can contribute to quantifying MS and establishing viewer-friendly VR by determining its qualities. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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16 pages, 765 KiB  

Open AccessReview

Therapeutic Use of VR Serious Games in the Treatment of Negative Schizophrenia Symptoms: A Systematic Review

by Beatriz Miranda, Pedro Miguel Moreira, Luís Romero and Paula Alexandra Rego

Healthcare 2022, 10(8), 1497; https://doi.org/10.3390/healthcare10081497 - 9 Aug 2022

Cited by 3 | Viewed by 1961

Abstract

Schizophrenia is a chronic brain disorder that affects 1 in every 300 people worldwide. This study intended to perform a systematic review to describe the state-of-the-art of interventions involving patients with negative symptoms of schizophrenia that use Virtual Reality (VR) games as a [...] Read more.

Schizophrenia is a chronic brain disorder that affects 1 in every 300 people worldwide. This study intended to perform a systematic review to describe the state-of-the-art of interventions involving patients with negative symptoms of schizophrenia that use Virtual Reality (VR) games as a complement to therapy, and to analyze the key features of such games. Literature research was conducted in three databases, namely, the Institute of Electrical and Electronics Engineers (IEEE), Scopus, and PubMed, to identify relevant publications dated from 2010 to 2021. Of the initial 74 publications found, only 11 satisfied the eligibility requirements and were included in this study. The results were then organized and displayed in a flow diagram. Overall, the results from the studies suggest that the use of VR in therapies enables an increase in social skills and a decrease in anxiety symptoms. The use of such technology in therapy has proven to be effective, although it still lacks features to provide better long-term results. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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20 pages, 6822 KiB  

Open AccessArticle

Building Korean DMZ Metaverse Using a Web-Based Metaverse Platform

by Sangsu Choi, Kajoong Yoon, Miae Kim, Jintak Yoo, Bonghyeon Lee, Inho Song and Jungyub Woo

Appl. Sci. 2022, 12(15), 7908; https://doi.org/10.3390/app12157908 - 7 Aug 2022

Cited by 14 | Viewed by 4237

Abstract

Metaverse is a compound word of “Meta” and “Universe”, meaning a world that transcends reality, a new virtual world. Due to the COVID-19 pandemic, non-face-to-face further accelerated the activation of the Metaverse. The Metaverse has the attractiveness of arousing user interest, high service [...] Read more.

Metaverse is a compound word of “Meta” and “Universe”, meaning a world that transcends reality, a new virtual world. Due to the COVID-19 pandemic, non-face-to-face further accelerated the activation of the Metaverse. The Metaverse has the attractiveness of arousing user interest, high service scalability, and the potential to combine multiple revenue models. Therefore, many industries are adopting the Metaverse. The Republic of Korea has been on a ceasefire, since 1953, after the Korean War. After the war, the DMZ was decided in an area of 2 km from north to south (total of 4 km), centered on the Military Demarcation Line (MDL). The DMZ area is the largest nature conservation area in Asia and a military area where public access is strictly restricted. The Ministry of Unification is trying to reduce tensions and establish peace in the DMZ area by raising the interest of Korean people, as well as people around the world, through the DMZ Metaverse application. The Korean government has its own e-Government framework and cloud operating environments. In order to adopt the Metaverse to Korean government agencies and operate them sustainably, it is essential to support the e-Government framework and the cloud environments. In this paper, the design features, architecture, models, and functions of OnTwins, a Metaverse platform serviceable in the Korean government IT operating environment, are elaborated in detail. The DMZ Metaverse public service built on the platform will also be introduced. Finally, after comparing it with other Metaverse platforms, future research directions are discussed. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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37 pages, 9164 KiB  

Open AccessArticle

Data Collection Framework for Context-Aware Virtual Reality Application Development in Unity: Case of Avatar Embodiment

by Jiyoung Moon, Minho Jeong, Sangmin Oh, Teemu H. Laine and Jungryul Seo

Sensors 2022, 22(12), 4623; https://doi.org/10.3390/s22124623 - 19 Jun 2022

Cited by 9 | Viewed by 3152

Abstract

Virtual Reality (VR) has been adopted as a leading technology for the metaverse, yet most previous VR systems provide one-size-fits-all experiences to users. Context-awareness in VR enables personalized experiences in the metaverse, such as improved embodiment and deeper integration of the real world [...] Read more.

Virtual Reality (VR) has been adopted as a leading technology for the metaverse, yet most previous VR systems provide one-size-fits-all experiences to users. Context-awareness in VR enables personalized experiences in the metaverse, such as improved embodiment and deeper integration of the real world and virtual worlds. Personalization requires context data from diverse sources. We proposed a reusable and extensible context data collection framework, ManySense VR, which unifies data collection from diverse sources for VR applications. ManySense VR was implemented in Unity based on extensible context data managers collecting data from data sources such as an eye tracker, electroencephalogram, pulse, respiration, galvanic skin response, facial tracker, and Open Weather Map. We used ManySense VR to build a context-aware embodiment VR scene where the user’s avatar is synchronized with their bodily actions. The performance evaluation of ManySense VR showed good performance in processor usage, frame rate, and memory footprint. Additionally, we conducted a qualitative formative evaluation by interviewing five developers (two males and three females; mean age: 22) after they used and extended ManySense VR. The participants expressed advantages (e.g., ease-of-use, learnability, familiarity, quickness, and extensibility), disadvantages (e.g., inconvenient/error-prone data query method and lack of diversity in callback methods), future application ideas, and improvement suggestions that indicate potential and can guide future development. In conclusion, ManySense VR is an efficient tool for researchers and developers to easily integrate context data into their Unity-based VR applications for the metaverse. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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15 pages, 2073 KiB  

Open AccessReview

Ship’s Digital Twin—A Review of Modelling Challenges and Applications

by Nur Assani, Petar Matić and Marko Katalinić

Appl. Sci. 2022, 12(12), 6039; https://doi.org/10.3390/app12126039 - 14 Jun 2022

Cited by 15 | Viewed by 3608

Abstract

The Ship’s Digital Twin (SDT) is a digital record of a ship’s behaviour or a software clone, which can be used to simulate scenarios that are expensive or hardly feasible to perform on a real object and especially in real time. The purpose [...] Read more.

The Ship’s Digital Twin (SDT) is a digital record of a ship’s behaviour or a software clone, which can be used to simulate scenarios that are expensive or hardly feasible to perform on a real object and especially in real time. The purpose of the SDT is to achieve cost reduction, obtain timely warnings of irregularities, and optimise individual ship system performances or the operation of the whole ship and to assist ship management. The aim of this paper is to describe the concept of the SDT and clarify some perplexities that may occur from initial introduction to concept. To that end, the paper identifies the steps in the SDT formulation process and methods used in each step of the process. Furthermore, a four-step iterative procedure for the SDT development is proposed. The applications of the concept are numerous, and some of them are presented in a review analysis in this paper. The presented analysis leads to a conclusion that should give some direction to future research in this area. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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28 pages, 2428 KiB  

Open AccessReview

Applications of Digital Twin across Industries: A Review

by Maulshree Singh, Rupal Srivastava, Evert Fuenmayor, Vladimir Kuts, Yuansong Qiao, Niall Murray and Declan Devine

Appl. Sci. 2022, 12(11), 5727; https://doi.org/10.3390/app12115727 - 4 Jun 2022

Cited by 73 | Viewed by 13703

Abstract

One of the most promising technologies that is driving digitalization in several industries is Digital Twin (DT). DT refers to the digital replica or model of any physical object (physical twin). What differentiates DT from simulation and other digital or CAD models is [...] Read more.

One of the most promising technologies that is driving digitalization in several industries is Digital Twin (DT). DT refers to the digital replica or model of any physical object (physical twin). What differentiates DT from simulation and other digital or CAD models is the automatic bidirectional exchange of data between digital and physical twins in real-time. The benefits of implementing DT in any sector include reduced operational costs and time, increased productivity, better decision making, improved predictive/preventive maintenance, etc. As a result, its implementation is expected to grow exponentially in the coming decades as, with the advent of Industry 4.0, products and systems have become more intelligent, relaying on collection and storing incremental amounts of data. Connecting that data effectively to DTs can open up many new opportunities and this paper explores different industrial sectors where the implementation of DT is taking advantage of these opportunities and how these opportunities are taking the industry forward. The paper covers the applications of DT in 13 different industries including the manufacturing, agriculture, education, construction, medicine, and retail, along with the industrial use case in these industries. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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19 pages, 10791 KiB  

Open AccessArticle

Home Environment Augmented Reality System Based on 3D Reconstruction of a Single Furniture Picture

by Hongtao Wei, Lei Tang, Wenshuo Wang and Jiaming Zhang

Sensors 2022, 22(11), 4020; https://doi.org/10.3390/s22114020 - 26 May 2022

Cited by 2 | Viewed by 2379

Abstract

With the popularization of the concept of “metaverse”, Augmented Reality (AR) technology is slowly being applied to people’s daily life as its underlying technology support. In recent years, rapid 3D reconstruction of interior furniture to meet AR shopping needs has become a new [...] Read more.

With the popularization of the concept of “metaverse”, Augmented Reality (AR) technology is slowly being applied to people’s daily life as its underlying technology support. In recent years, rapid 3D reconstruction of interior furniture to meet AR shopping needs has become a new method. In this paper, a virtual home environment system is designed and the related core technologies in the system are studied. Background removal and instance segmentation are performed for furniture images containing complex backgrounds, and a Bayesian Classifier and GrabCut (BCGC) algorithm is proposed to improve on the traditional foreground background separation technique. The reconstruction part takes the classical occupancy network reconstruction algorithm as the network basis and proposes a precise occupancy network (PONet) algorithm, which can reconstruct the structural details of furniture images, and the model accuracy is improved. Because the traditional 3D registration model is prone to the problems of model position shift and inaccurate matching with the scene, the AKAZE-based tracking registration algorithm is improved, and a Multiple Filtering-AKAZE (MF-AKAZE) based on AKAZE is proposed to remove the matching points. The matching accuracy is increased by improving the RANSAC filtering mis-matching algorithm based on further screening of the matching results. Finally, the system is verified to realize the function of the AR visualization furniture model, which can better complete the reconstruction as well as registration effect. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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17 pages, 2775 KiB  

Open AccessArticle

Mixed-Reality-Enhanced Human–Robot Interaction with an Imitation-Based Mapping Approach for Intuitive Teleoperation of a Robotic Arm-Hand System

by Yun-Peng Su, Xiao-Qi Chen, Tony Zhou, Christopher Pretty and Geoffrey Chase

Appl. Sci. 2022, 12(9), 4740; https://doi.org/10.3390/app12094740 - 8 May 2022

Cited by 17 | Viewed by 5931

Abstract

This paper presents an integrated mapping of motion and visualization scheme based on a Mixed Reality (MR) subspace approach for the intuitive and immersive telemanipulation of robotic arm-hand systems. The effectiveness of different control-feedback methods for the teleoperation system is validated and compared. [...] Read more.

This paper presents an integrated mapping of motion and visualization scheme based on a Mixed Reality (MR) subspace approach for the intuitive and immersive telemanipulation of robotic arm-hand systems. The effectiveness of different control-feedback methods for the teleoperation system is validated and compared. The robotic arm-hand system consists of a 6 Degrees-of-Freedom (DOF) industrial manipulator and a low-cost 2-finger gripper, which can be manipulated in a natural manner by novice users physically distant from the working site. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time 3D visual feedback from the robot working site. Imitation-based velocity-centric motion mapping is implemented via the MR subspace to accurately track operator hand movements for robot motion control and enables spatial velocity-based control of the robot Tool Center Point (TCP). The user control space and robot working space are overlaid through the MR subspace, and the local user and a digital twin of the remote robot share the same environment in the MR subspace. The MR-based motion and visualization mapping scheme for telerobotics is compared to conventional 2D Baseline and MR tele-control paradigms over two tabletop object manipulation experiments. A user survey of 24 participants was conducted to demonstrate the effectiveness and performance enhancements enabled by the proposed system. The MR-subspace-integrated 3D mapping of motion and visualization scheme reduced the aggregate task completion time by 48% compared to the 2D Baseline module and 29%, compared to the MR SpaceMouse module. The perceived workload decreased by 32% and 22%, compared to the 2D Baseline and MR SpaceMouse approaches. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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19 pages, 8347 KiB  

Open AccessArticle

‘Sustainable’ Recording and Preservation of Zangniang Stupa and Sangzhou Lamasery in Qinghai, China with Heritage Building Information Model

by Chaoran Xu, Yi Zhao and Cong Wu

Sustainability 2022, 14(8), 4549; https://doi.org/10.3390/su14084549 - 11 Apr 2022

Cited by 1 | Viewed by 1565

Abstract

This paper research and discusses the ‘sustainable’ workflow and heritage recording method of historic building information modelling (HBIM) for Chinese Tibetan architecture and pagodas and explains the vital role of recording heritage information to protect cultural relics. Considering the Tibetan Buddhist Pagoda in [...] Read more.

This paper research and discusses the ‘sustainable’ workflow and heritage recording method of historic building information modelling (HBIM) for Chinese Tibetan architecture and pagodas and explains the vital role of recording heritage information to protect cultural relics. Considering the Tibetan Buddhist Pagoda in Yushu, Qinghai, China, this paper explores the collaborative modelling mechanism and ideas between heritage surveying and scanning information and software, and the problems of these two methods. Through research, we have obtained successful cases of HBIM based on field scanning and mapping, online software collaborative modelling (Rhino, Bentley, Autodesk Computer-Aided Design), sustainable management, and display. It is an information model constructed according to construction logic and accurate information and one that realises sustainable and full-cycle recording functions by continuous recording, updating, and iterating. This method removes a limitation of HBIM in that it considers one-time information construction and delivery mode but does not consider and explore sustainable recording work. It will significantly promote more records on the heritage information of Tibetan architecture. The results will also directly serve the protection of architectural heritage in Qinghai Province, China and the ‘Silk Road (South Asia Section) Transnational Serial Application for World Heritage’ work. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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15 pages, 15217 KiB  

Open AccessArticle

Generating the Regular Axis from Irregular Column Grids through Genetic Algorithm

by Xi Wang, Cong Wu and Chengjun Bai

Appl. Sci. 2022, 12(4), 2109; https://doi.org/10.3390/app12042109 - 17 Feb 2022

Cited by 6 | Viewed by 1781

Abstract

Historic building information modeling (HBIM) provides an index frame for digital documentation of the cultural heritage, as a continuous process of reverse engineering. The index frame should be a regular model, with a clear comprehension of each component; consequently, associated knowledge could be [...] Read more.

Historic building information modeling (HBIM) provides an index frame for digital documentation of the cultural heritage, as a continuous process of reverse engineering. The index frame should be a regular model, with a clear comprehension of each component; consequently, associated knowledge could be live-updated with the investigation progress. Therefore, the method of data registration stresses its importance. The axis is fundamental for Chinese traditional architecture as the basis for positioning all components in wooden structures. However, displacement often happens. To correct the displacement while modeling, the hypothetical axis should be determined first. This paper thus proposes a method of generating the regular axis from irregular column grids and aims to develop an automatic solution that is repeatable and transplantable. The finite element modeling (FEM) abstracts the actual problem to enable numerical calculation. Starting from a candidate solution, the genetic algorithm calculates a solution closest to the expectation from the possible solutions in several minutes. The standard deviation is used to measure the amount of displacement based on the hypothetical axis, which is expected to be minimum. This method is compatible with most kinds of input data, e.g., point cloud, excel data, 2D drawing, mesh model, etc., and applied to a World Heritage Site in Qufu (Shandong, China). The results show the displacement of columns with visual expression and numerical analysis and prove that the proposed method is repeatable and traceable and can easily be applied to different projects by changing input parameters. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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10 pages, 4219 KiB  

Open AccessCase Report

Subcutaneous Emphysema Related to Dental Treatment: A Case Series

by Rieko Shimizu, Shintaro Sukegawa, Yuka Sukegawa, Kazuaki Hasegawa, Sawako Ono, Ai Fujimura, Izumi Yamamoto, Soichiro Ibaragi, Akira Sasaki and Yoshihiko Furuki

Healthcare 2022, 10(2), 290; https://doi.org/10.3390/healthcare10020290 - 1 Feb 2022

Cited by 3 | Viewed by 2997

Abstract

Cervicofacial subcutaneous emphysema (SE) is primarily caused by dental treatment introducing gas into the subcutaneous tissue. Air rapidly dissects into the subcutaneous tissue with face and neck swelling, leading to respiratory distress, patient discomfort, and chest pain. Computed tomography (CT) can detect spreading [...] Read more.

Cervicofacial subcutaneous emphysema (SE) is primarily caused by dental treatment introducing gas into the subcutaneous tissue. Air rapidly dissects into the subcutaneous tissue with face and neck swelling, leading to respiratory distress, patient discomfort, and chest pain. Computed tomography (CT) can detect spreading SE patterns. However, the true volume of SE and the degree of air changes in the body over time remain unknown. We evaluated the healing process of SE and the temporal changes in the volume of emphysema in three cases detected using our hospital’s electronic health record systems based on inclusion and exclusion criteria over the past 10 years, with CT and three-dimensional (3D) images. The first case was a 46-year-old woman who presented with complaints of swelling from her right eyelid to the neck and clavicles, pain on swallowing, respiratory distress, and hoarseness. The second case was a 35-year-old man who presented with complaints of swelling over the face. The third case was a 36-year-old man who presented with complaints of swelling from the left cheek to the neck. CT revealed SE and pneumomediastinum in all cases. All the patients were administered an antibacterial drug. The CT and 3D images showed an improvement in emphysema 3 days after the onset, with more than half of the volume reduction in emphysema. This made it possible to evaluate the changes in the air content of SE. Observation with CT until the healing process of SE is completed is crucial, and 3D images also help evaluate changes over time. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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14 pages, 5269 KiB  

Open AccessArticle

3D Static Point Cloud Registration by Estimating Temporal Human Pose at Multiview

by Byung-Seo Park, Woosuk Kim, Jin-Kyum Kim, Eui Seok Hwang, Dong-Wook Kim and Young-Ho Seo

Sensors 2022, 22(3), 1097; https://doi.org/10.3390/s22031097 - 31 Jan 2022

Cited by 1 | Viewed by 2741

Abstract

This paper proposes a new technique for performing 3D static-point cloud registration after calibrating a multi-view RGB-D camera using a 3D (dimensional) joint set. Consistent feature points are required to calibrate a multi-view camera, and accurate feature points are necessary to obtain high-accuracy [...] Read more.

This paper proposes a new technique for performing 3D static-point cloud registration after calibrating a multi-view RGB-D camera using a 3D (dimensional) joint set. Consistent feature points are required to calibrate a multi-view camera, and accurate feature points are necessary to obtain high-accuracy calibration results. In general, a special tool, such as a chessboard, is used to calibrate a multi-view camera. However, this paper uses joints on a human skeleton as feature points for calibrating a multi-view camera to perform calibration efficiently without special tools. We propose an RGB-D-based calibration algorithm that uses the joint coordinates of the 3D joint set obtained through pose estimation as feature points. Since human body information captured by the multi-view camera may be incomplete, a joint set predicted based on image information obtained through this may be incomplete. After efficiently integrating a plurality of incomplete joint sets into one joint set, multi-view cameras can be calibrated by using the combined joint set to obtain extrinsic matrices. To increase the accuracy of calibration, multiple joint sets are used for optimization through temporal iteration. We prove through experiments that it is possible to calibrate a multi-view camera using a large number of incomplete joint sets. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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30 pages, 3176 KiB  

Open AccessArticle

Eye-Tracking in Interactive Virtual Environments: Implementation and Evaluation

by Pavel Ugwitz, Ondřej Kvarda, Zuzana Juříková, Čeněk Šašinka and Sascha Tamm

Appl. Sci. 2022, 12(3), 1027; https://doi.org/10.3390/app12031027 - 19 Jan 2022

Cited by 16 | Viewed by 16556

Abstract

Not all eye-tracking methodology and data processing are equal. While the use of eye-tracking is intricate because of its grounding in visual physiology, traditional 2D eye-tracking methods are supported by software, tools, and reference studies. This is not so true for eye-tracking methods [...] Read more.

Not all eye-tracking methodology and data processing are equal. While the use of eye-tracking is intricate because of its grounding in visual physiology, traditional 2D eye-tracking methods are supported by software, tools, and reference studies. This is not so true for eye-tracking methods applied in virtual reality (imaginary 3D environments). Previous research regarded the domain of eye-tracking in 3D virtual reality as an untamed realm with unaddressed issues. The present paper explores these issues, discusses possible solutions at a theoretical level, and offers example implementations. The paper also proposes a workflow and software architecture that encompasses an entire experimental scenario, including virtual scene preparation and operationalization of visual stimuli, experimental data collection and considerations for ambiguous visual stimuli, post-hoc data correction, data aggregation, and visualization. The paper is accompanied by examples of eye-tracking data collection and evaluation based on ongoing research of indoor evacuation behavior. Full article

(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)

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