Methods to Calibrate Projection Transformation Parameters for See-Through Head-Mounted Displays

1996 ◽  
Vol 5 (1) ◽  
pp. 122-135 ◽  
Author(s):  
Takashi Oishi ◽  
Susumu Tachi
Keyword(s):  
Virtual Environment ◽  
Least Squares Method ◽  
Calibration Method ◽  
The Real ◽  
Virtual Objects ◽  
Real Environment ◽  
Calibration Methods ◽  
Head Mounted Displays ◽  
Transformation Parameters ◽  
Projection Transformation

See-through head-mounted displays (STHMDs), which superimpose the virtual environment generated by computer graphics (CG) on the real world, are expected to be able to vividly display various simulations and designs by using both the real environment and the virtual environment around us. However, we must ensure that the virtual environment is superimposed exactly on the real environment because both environments are visible. Disagreement in matching locations and size between real and virtual objects is likely to occur between the world coordinates of the real environment where the STHMD user actually exists and those of the virtual environment described as parameters of CG. This disagreement directly causes displacement of locations where virtual objects are superimposed. The STHMD must be calibrated so that the virtual environment is superimposed properly. Among the causes of such errors, we focus both on systematic errors of projection transformation parameters caused in manufacturing and differences between actual and supposed location of user's eye on STHMD when in use, and propose a calibration method to eliminate these effects. In the calibration method, the virtual cursor drawn in the virtual environment is directly fitted onto targets in the real environment. Based on the result of fitting, the least-squares method identifies values of the parameters that minimize differences between locations of the virtual cursor in the virtual environment and targets in the real environment. After we describe the calibration methods, we also report the result of this application to the STHMD that we have made. The result is accurate enough to prove the effectiveness of the calibration methods.

scholarly journals Colocation for SLAM-Tracked VR Headsets with Hand Tracking

Computers ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 58
Author(s):  
Dennis Reimer ◽  
Iana Podkosova ◽  
Daniel Scherzer ◽  
Hannes Kaufmann
Keyword(s):  
Virtual Reality ◽  
Fixed Point ◽  
Virtual Environment ◽  
Tracking System ◽  
Calibration Method ◽  
Hand Tracking ◽  
Experimental Procedure ◽  
The Third ◽  
Calibration Methods ◽  
Head Mounted Displays

In colocated multi-user Virtual Reality applications, relative user positions in the virtual environment need to match their relative positions in the physical tracking space. A mismatch between virtual and real relative user positions might lead to harmful events such as physical user collisions. This paper examines three calibration methods that enable colocated Virtual Reality scenarios for SLAM-tracked head-mounted displays without the need for an external tracking system. Two of these methods—fixed-point calibration and marked-based calibration—have been described in previous research; the third method that uses hand tracking capabilities of head-mounted displays is novel. We evaluated the accuracy of these three methods in an experimental procedure with two colocated Oculus Quest devices. The results of the evaluation show that our novel hand tracking-based calibration method provides better accuracy and consistency while at the same time being easy to execute. The paper further discusses the potential of all evaluated calibration methods.

scholarly journals RATIOS OF DIFFERENT TYPES OF ACTIVITY DEPENDING ON THE FREQUENCY OF TRANSFER OF SOCIAL ACTIVITY FROM THE REAL ENVIRONMENT TO THE VIRTUAL ENVIRONMENT AND VICE VERSA

2019 ◽  
Vol 29 (3) ◽  
pp. 286-290
Author(s):  
A.I. Zagranichny
Keyword(s):  
Virtual Environment ◽  
Social Activity ◽  
Educational Activity ◽  
Young Specialist ◽  
Play Activity ◽  
The Real ◽  
Real Environment ◽  
Different Types ◽  
Communicative Activity

The article presents the results of a research of different types of activity depending on the frequency of transfer of social activity from the real environment to the virtual environment and vice versa. In the course of the research the following types of activity were identified: play activity; educational activity; work; communicative activity. 214 respondents from the following cities participated in the research: Balakovo, Saratov, Moscow. They were at the age of 15 to 24 years. 52% of them were women. They had the following social statuses: "pupil", "student", "young specialist". The correlation interrelation between the specified types of activity and the frequency of transfer of social activity from one environment into another has been analyzed and interpreted. In the course of the research the following results were received: the frequency of transfer of social activity from the real environment to the virtual environment has a direct positive link with such types of activity as play activity (r=0.221; p <0.01); educational activity (r=0.228; p <0.01) and communicative activity (r=0.346; p <0.01). The frequency of transfer of social activity from the virtual environment to the real one has a direct positive link only with two types of activity: educational activity (r=0.188; p <0.05) and communicative activity (r=0.331; p <0.01).

scholarly journals Virtual Object Replacement Based on Real Environments: Potential Application in Augmented Reality Systems

2019 ◽  
Vol 9 (9) ◽  
pp. 1797
Author(s):  
Chen ◽  
Lin
Keyword(s):  
Augmented Reality ◽  
Virtual Environments ◽  
Real World ◽  
Point Clouds ◽  
Virtual Object ◽  
Movement Trajectory ◽  
The Real ◽  
Virtual Objects ◽  
Real Environment ◽  
Localization And Mapping

Augmented reality (AR) is an emerging technology that allows users to interact with simulated environments, including those emulating scenes in the real world. Most current AR technologies involve the placement of virtual objects within these scenes. However, difficulties in modeling real-world objects greatly limit the scope of the simulation, and thus the depth of the user experience. In this study, we developed a process by which to realize virtual environments that are based entirely on scenes in the real world. In modeling the real world, the proposed scheme divides scenes into discrete objects, which are then replaced with virtual objects. This enables users to interact in and with virtual environments without limitations. An RGB-D camera is used in conjunction with simultaneous localization and mapping (SLAM) to obtain the movement trajectory of the user and derive information related to the real environment. In modeling the environment, graph-based segmentation is used to segment point clouds and perform object segmentation to enable the subsequent replacement of objects with equivalent virtual entities. Superquadrics are used to derive shape parameters and location information from the segmentation results in order to ensure that the scale of the virtual objects matches the original objects in the real world. Only after the objects have been replaced with their virtual counterparts in the real environment converted into a virtual scene. Experiments involving the emulation of real-world locations demonstrated the feasibility of the proposed rendering scheme. A rock-climbing application scenario is finally presented to illustrate the potential use of the proposed system in AR applications.

Design and control of a haptic interactive motion simulator for virtual entertainment systems

Robotica ◽  
2009 ◽  
Vol 28 (1) ◽  
pp. 47-56 ◽  
Author(s):  
M. Karkoub ◽  
M.-G. Her ◽  
J.-M. Chen
Keyword(s):  
Virtual Reality ◽  
Virtual Environment ◽  
Haptic Feedback ◽  
Environmental Changes ◽  
Bilateral Control ◽  
The Real ◽  
Real Environment ◽  
Control Interface ◽  
Motion Simulator ◽  
Nyquist Stability

SUMMARYIn this paper, an interactive virtual reality motion simulator is designed and analyzed. The main components of the system include a bilateral control interface, networking, a virtual environment, and a motion simulator. The virtual reality entertainment system uses a virtual environment that enables the operator to feel the actual feedback through a haptic interface as well as the distorted motion from the virtual environment just as s/he would in the real environment. The control scheme for the simulator uses the change in velocity and acceleration that the operator imposes on the joystick, the environmental changes imposed on the motion simulator, and the haptic feedback to the operator to maneuver the simulator in the real environment. The stability of the closed-loop system is analyzed based on the Nyquist stability criteria. It is shown that the proposed design for the simulator system works well and the theoretical findings are validated experimentally.

scholarly journals Augmented Reality Research and Applications in Education

2021 ◽  
Author(s):  
Ezgi Pelin Yildiz
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Real Time ◽  
Virtual Environment ◽  
Real World ◽  
The Real ◽  
Virtual Objects ◽  
Physical Environments ◽  
Real Objects ◽  
As If

Augmented reality is defined as the technology in which virtual objects are blended with the real world and also interact with each other. Although augmented reality applications are used in many areas, the most important of these areas is the field of education. AR technology allows the combination of real objects and virtual information in order to increase students’ interaction with physical environments and facilitate their learning. Developing technology enables students to learn complex topics in a fun and easy way through virtual reality devices. Students interact with objects in the virtual environment and can learn more about it. For example; by organizing digital tours to a museum or zoo in a completely different country, lessons can be taught in the company of a teacher as if they were there at that moment. In the light of all these, this study is a compilation study. In this context, augmented reality technologies were introduced and attention was drawn to their use in different fields of education with their examples. As a suggestion at the end of the study, it was emphasized that the prepared sections should be carefully read by the educators and put into practice in their lessons. In addition it was also pointed out that it should be preferred in order to communicate effectively with students by interacting in real time, especially during the pandemic process.

scholarly journals Mixed Reality Enhanced User Interactive Path Planning for Omnidirectional Mobile Robot

2020 ◽  
Vol 10 (3) ◽  
pp. 1135 ◽  
Author(s):  
Mulun Wu ◽  
Shi-Lu Dai ◽  
Chenguang Yang
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Mixed Reality ◽  
Avoidance Performance ◽  
Motion Path ◽  
The Real ◽  
Virtual Objects ◽  
Omnidirectional Mobile Robot ◽  
Real Environment ◽  
Control Command

This paper proposes a novel control system for the path planning of an omnidirectional mobile robot based on mixed reality. Most research on mobile robots is carried out in a completely real environment or a completely virtual environment. However, a real environment containing virtual objects has important actual applications. The proposed system can control the movement of the mobile robot in the real environment, as well as the interaction between the mobile robot’s motion and virtual objects which can be added to a real environment. First, an interactive interface is presented in the mixed reality device HoloLens. The interface can display the map, path, control command, and other information related to the mobile robot, and it can add virtual objects to the real map to realize a real-time interaction between the mobile robot and the virtual objects. Then, the original path planning algorithm, vector field histogram* (VFH*), is modified in the aspects of the threshold, candidate direction selection, and cost function, to make it more suitable for the scene with virtual objects, reduce the number of calculations required, and improve the security. Experimental results demonstrated that this proposed method can generate the motion path of the mobile robot according to the specific requirements of the operator, and achieve a good obstacle avoidance performance.

Stationary walking performance of post-stroke patients and healthy individuals in real and virtual non-immersive environments

2021 ◽  
pp. 1-7
Author(s):  
Ailton Barbosa da Silva Júnior ◽  
Beatriz Cristina Medeiros de Lucena ◽  
Edson Meneses Silva-Filho ◽  
Aline Braga Galvão Silveira Fernandes
Keyword(s):  
Range Of Motion ◽  
Virtual Environment ◽  
Lower Limb ◽  
Healthy Individuals ◽  
Stroke Patients ◽  
Immersive Environments ◽  
The Real ◽  
Post Stroke ◽  
Real Environment ◽  
Immersive Virtual Environment

BACKGROUND: Several therapies are being used for the rehabilitation of stroke patients, such as Virtual Reality (VR) which has emerged as an interactive intervention to motivate and rehabilitate post-stroke patients. However, data comparison between the virtual and real environments is inconclusive. Thus, this study aimed to compare the kinematics and performance of the affected lower limb of post-stroke patients and healthy individuals during stationary walking activity between the real and virtual non-immersive environments. METHODS: A cross-sectional study was conducted with 10 stroke patients and 10 healthy individuals, matched for gender and age. The participants performed stationary walking in a real and non-immersive virtual environment (Wii Fit Plus® –Running mode) for 3 minutes in random order. The performance was measured in both environments using the number of steps, while the kinematics was assessed by calculating the mean maximum flexion and extension of each joint (hip, knee, and ankle) of the affected lower limb. RESULTS: Post-stroke patients performed a higher total number of steps (p = 0.042), mainly in the third minute (p = 0.011), less knee flexion (p = 0.001) and total knee range of motion (p = 0.001) in the virtual compared with the real environment. CONCLUSIONS: Post-stroke patients performed more steps, with a faster cadence and smaller knee range of motion on the affected side in non-immersive virtual environment compared with the real environment.

scholarly journals Large Relics Scenario-Based Visualization Using Head-Mounted Displays

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Hui Xu ◽  
Jiawan Zhang
Keyword(s):  
Virtual Reality ◽  
Strong Interaction ◽  
Sense Organ ◽  
Research Issue ◽  
Information Display ◽  
The Real ◽  
Ancient Civilization ◽  
Real Environment ◽  
Head Mounted Displays ◽  
Virtual Exhibition

Most visitors come to visit museums; in reality, few immersive solutions support the senses experience. Virtual reality (VR) technology attaches the virtual information from the real environment. Applying the VR technology in the 3D relic information display and visualization in the museum field is a hot research issue. However, most current solutions of relics are one-sided, only focusing on the virtual exhibition, lack of associations with actual function, and senses experience, especially the large artistic cultural relics. The scenario-based virtual exhibition solution is an available approach to allow visitors to imitate ancient artist and provide relatively experience in the form of content and sense organ of ancient art. It converts large relics into “digital large relics” and enables experiencing performance of ancient civilization in person. The solution presents relics to the visitors in a more direct and vivid manner and with innovative forms, strong interaction, and intelligence, thereby improving the interests and satisfaction among visitors in this type of relic exhibition. Besides, it also provides visitors with a convenient way to experience and learn ritual and culture. Evaluation and conclusion can be drawn that most participants appreciated this solution in clear interface and completion aspects.

scholarly journals Aplikasi Simulasi Public Speaking Berbasis Android Dengan Unity 3D

Repositor ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 215
Author(s):  
Alfian Hanafi ◽  
Lailatul Husniah ◽  
Ali Sofyan Kholimi
Keyword(s):  
Virtual Reality ◽  
Success Rate ◽  
Virtual Environment ◽  
Scoring System ◽  
Public Speaking ◽  
The Real ◽  
Real Environment ◽  
Control Factors ◽  
Unity 3D ◽  
Test Application

ABSTRAKPublic Speaking merupakan suatu kegiatan dimana pembicara atau penyaji akan menyajikan suatu orasi kepada audien secara langsung. Public Speaking memiliki fungsi sebagai media untuk memberi informasi kepada audien, mengajak atau membujuk audien untuk melakukan, mempercayai sesuatu yang diinginkan pembicara dan memberi hiburan kepada audien. Kegiatan Public Speaking dalam masyarakat memiliki peran penting karena mampu meningkatkan keberanian seseorang untuk bicara di depan umum, selain itu Public Speaking dapat meningkatkan rasa kepemimpinan seseorang. Namun, dalam praktiknya banyak orang yang masih merasa gugup, tidak siap, bahkan tidak berani melakukan Public Speaking. Alasan itulah yang melandasi dibuatnya aplikasi simulasi pelatihan Public Speaking dengan memanfaatkan teknologi Virtual Reality (VR) yang berbasis android.VR sendiri merupakan teknologi yang memungkinkan penggunannya untuk melakukan simulasi di dunia maya secara berkelanjutan tanpa mengeluarkan biaya yang banyak. Hal ini dikarenakan VR mampu mensimulasikan lingkungan virtual dengan baik, yang tentunya akan membuat penggunanya merasa seperti di lingkungan nyata. Dalam aplikasi ini sendiri menyediakan lingkungan virtual yang bisa digunakan pengguna untuk melakukan simulasi Public Speaking, dalam menentukan tingkat keberhasilan aplikasi, maka digunakanlah sistem penilaian yang akan mengukur tingkat keberhasilan aplikasi dalam membantu melatih pengguna melakukan Public Speaking.  Terdapat 4 (empat) faktor sebagai acuan penilaian aplikasi yaitu: Control Factors, Sensory Factors, Distraction Factors, Realism Factors. Dalam hasil pengujian yang dilakukan didapatkan hasil bahwa aplikasi mampu membantu pengguna melakukan simulasi Public Speaking.ABSTRACT Public Speaking is an activity where the speaker or presenter will present an oration to the audience directly. Public Speaking has a function as a medium to inform the audience, invite or persuade audiences to perform, to believe in something the speaker wants and to entertain the audience. Public Speaking activities in the society have an important role because it can increase someone courage to speak in public, in addition Public Speaking can increase someone sense of leadership. However, in practice many people are still feeling nervous, unprepared, not even daring to do Public Speaking. The reason that underlies the creation of simulation applications Public Speaking training by utilizing technology Virtual Reality (VR) based on android.VR itself is a technology that allows it’s users to perform simulations in virtual environment on a sustainable basis without spending a lot money. This is because the VR is able to simulate a virtual environment really well, which of course will make users feel like in the real environment. In this application it’s provides a virtual environment that can be used by users to perform Public Speaking simulations, in determining the success rate of the application, then used a scoring system that will measure the success rate of the application in helping train users perform Public Speaking. There are 4 (four) factors as the appraisal that is: Control Factors, Sensory Factors, Distraction Factors, Realism Factors. In the results of test, application itself obtain the results that it is able to help users to simulate Public Speaking. 

scholarly journals Pemodelan Lingkungan Virtual untuk Interaksi Avatar Berbasis Context Pada Proyek Digital Life at Campus (DiL@C)

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Haruno Sajati ◽  
Lukito Edi Nugroho ◽  
Ridi Ferdiana
Keyword(s):  
Information Technology ◽  
Virtual Environment ◽  
System Architecture ◽  
Communication System ◽  
Virtual World ◽  
Access To Information ◽  
The Real ◽  
Virtual Objects ◽  
Campus Activities

Abstract. Campus activities that use information technology increasing rapidly, these activities e.g. studying activity, access to information and so on. The increased activities forces instance has an "assistants" who can help the real user to complete their works and responsibilities. Virtual world allows the user to be in a different context so that it can follow a different activity at one time. Avatar requires a virtual Environment for the activity. This research build a model in virtual world (VES) that would bring together between avatars, virtual objects and context to work in a scenario in Digital Life at Campus (Dil@C). Design written in this paper to formulate a model of Context based communication, system architecture and implementation that can be applied in the virtual world.Keywords: DiL@C, avatar, context, Virtual Environment System (VES). Abstrak. Aktifitas kampus yang memanfaatkan teknologi informasi semakin banyak, Aktifitas ini contohnya perkuliahan, akses informasi dan lain-lain. Peningkatan aktifitas ini memaksa instance di dalam kampus memiliki ”asisten” yang dapat membantu real user untuk menyelesaikan pekerjaan dan tanggung jawabnya. Dunia virtual memungkinkan user dapat berada pada konteks yang berbeda sehingga dapat mengikuti aktifitas yang berbeda pada satu waktu. Pengembangan model avatar yang merepresentasikan user dalam dunia maya membutuhkan lingkungan virtual untuk beraktifitas. Penelitian ini memodelkan sebuah dunia virtual (VES) yang dapat mempertemukan antara avatar, obyek-obyek virtual dan konteks untuk bekerja dalam sebuah skenario dalam Digital Life at Campus (DiL@C). Perancangan yang ditulis dalam paper ini merumuskan model komunikasi berbasis konteks, arsitektur sistem dan implementasi yang bisa diterapkan dalam dunia virtual.Kata Kunci: DiL@C, avatar, konteks, Virtual Environment System (VES).

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