Fiber-optic-based human-computer interaction device for VR systems

Extended-Reality Technologies: An Overview of Emerging Applications in Medical Education and Clinical Care.

With the rapid development of science and technology, virtual reality (VR) systems have developed rapidly. VR systems can be applied in many fields such as education, medical, military, and probing. According to the survey, the VR system will have a delay in the process of acquisition, transmission and processing, and more than 40% of the human body will have motion sickness after experiencing VR. The cause of motion sickness is delay. Accurate measurement of delays therefore helps to resolve motion sickness in the virtual world and provides guidance for the upgrade of these systems. In response to the existing problems, our research team designed a low-cost, high-performance experimental equipment that uses a single-chip microcomputer and a PIN photodiode as the hardware core of the delay detection device. The light intensity changes are used to determine the start and end of the detection. The algorithm calculates the delay time of the VR device.

Patients undergoing Magnetic Resonance Imaging (MRI) often experience anxiety and sometimes distress prior to and during scanning. Here a full MRI compatible virtual reality (VR) system is described and tested with the aim of creating a radically different experience. Potential benefits could accrue from the strong sense of immersion that can be created with VR, which could create sense experiences designed to avoid the perception of being enclosed and could also provide new modes of diversion and interaction that could make even lengthy MRI examinations much less challenging. Most current VR systems rely on head mounted displays combined with head motion tracking to achieve and maintain a visceral sense of a tangible virtual world, but this technology and approach encourages physical motion, which would be unacceptable and could be physically incompatible for MRI. The proposed VR system uses gaze tracking to control and interact with a virtual world. MRI compatible cameras are used to allow real time eye tracking and robust gaze tracking is achieved through an adaptive calibration strategy in which each successive VR interaction initiated by the subject updates the gaze estimation model. A dedicated VR framework has been developed including a rich virtual world and gaze-controlled game content. To aid in achieving immersive experiences physical sensations, including noise, vibration and proprioception associated with patient table movements, have been made congruent with the presented virtual scene. A live video link allows subject-carer interaction, projecting a supportive presence into the virtual world.

In recent years virtual environments (VEs) have become more and more popular and widespread due to the requirements of numerous application areas in particular in the 3D city visualization domain. Virtual reality (VR) systems, which make use of tracking technologies and stereoscopic projections of three-dimensional synthetic worlds, support better exploration of complex datasets. However, due to the limited interaction space usually provided by the range of the tracking sensors, users can explore only a portion of the virtual environment (VE). Redirected walking allows users to walk through large-scale immersive virtual environments (IVEs) such as virtual city models, while physically remaining in a reasonably small workspace by intentionally injecting scene motion into the IVE. With redirected walking users are guided on physical paths that may differ from the paths they perceive in the virtual world. The authors have conducted experiments in order to quantify how much humans can unknowingly be redirected. In this chapter they present the results of this study and the implications for virtual locomotion user interfaces that allow users to view arbitrary real world locations, before the users actually travel there in a natural environment.

Virtual Reality (VR) systems are used to distract patients from their current condition and immerse them in a virtual world where they are able to do many virtual activities while receiving their treatment. It was observed that VR systems improve the patent state of mind thereby improving their immune system. In this paper we study the role of VR in improving pain threshold for chemotherapy and burn patients. Unfortunately not all patients are able to use VR equipments, for example burn patents are unable to use VR head mounts and gloves. To design a VR software and hardware that could be used for every patent is close to impossible. In this paper we introduce the benefits and challenges of using VR systems as an added therapy to reduce pain sensation; we also give the general technical requirements for such system.

This paper describes a study aimed at developing and applying a method for comparing the user experience (UX) of virtual reality (VR) systems, in order to identify aspects that differentiate VR systems from a user perspective as well as aspects that users consider important when selecting a VR system. A within-subjects study was conducted, in which twelve participants played a VR game using four different VR systems (i.e., VR headsets and hand controllers). The UX was evaluated through semi-structured interviews and questionnaires. Headset comfort, fit, and perceived image quality as well as unrestricted mobility (i.e., untethered headsets) were identified as important aspects for the UX. Hand controllers that allowed more natural interaction were generally preferred. Image sharpness and headset comfort were considered the most important aspects for selecting a VR system. The study demonstrated that the method can be applied and generate insights into the UX of VR systems.

Background and Purpose: Repetitive practice improves function and facilitates cortical plasticity after stroke. Virtual reality (VR) systems have the potential to provide motivating and safe repetitive practice with minimal supervision. The purpose of this case study is to look at the effect of a VR system, activated by surface electromyography of dorsiflexors and plantarflexors, on gait velocity, function, and kinematics. Method: The first person randomized to the treatment group of a larger study was chosen for this case. She was 51 years old and 9 months poststroke. She received treatment 3 times per week for 8 weeks. Each 60-minute session consisted of both structured lower extremity exercise and VR ankle activities. Results: After intervention, the subject demonstrated increased gait speed and decreased time to perform the modified Emory Functional Ambulation Profile. Gait kinematics demonstrated improved ankle motion and plantarflexion moments at push off. Discussion: The improved gait speed, possibly due to increased ankle plantarflexion motion and moments, resulted in a more normalized trailing limb posture. This case study suggests that ankle to computer VR systems may help stroke patients improve gait function. This VR system has potential as an adjunctive therapy or home program requiring minimal supervision.

Digital restoration of fragmentary human skeletal remains: Testing the feasibility of virtual reality

The Reality of Virtual Reality in Echocardiography Education?

In order to improve the efficiency of information acquisition and task selection in Virtual Reality (VR) systems, enhance the interactive experience, and reduce cognitive load for users, it is crucial to effectively organize and leverage user cognitive psychology and design elements during the VR scene design phase. This paper focuses on analyzing the low cognitive load requirements of users and the need for a satisfactory user perceptual experience based on the cognitive resource theory. We propose a method for optimizing the design of VR system scenario tasks under low cognitive load requirements. By utilizing human-computer hybrid intelligent assistance for predicting user cognitive load and incorporating intelligent optimization genetic algorithms into the optimization of VR system design elements, we aim to minimize cognitive load as the objective function based on the principle of low cognitive load. Important knowledge granularity nodes are used as fitness functions in the optimization process of VR system design resource elements. An application study is conducted, combining the multi-channel cognition in a smart city VR system task information interface, to optimize the system resource features. The study validates and compares the solutions obtained through traditional design processes and the solutions optimized by the method proposed in this paper, using virtual reality eye-tracking experiments for the same design task requirements in VR systems. The results demonstrate that users experience lower cognitive load and better task operation experience when interacting with the optimized solutions proposed in this paper. Therefore, the optimization method studied in this paper can serve as a reference for the construction of virtual reality systems.

In this tutorial we will present the infrastructure required, both software and hardware, to create the Virtual Reality (VR) illusion. The history and the application areas of VR will be presented. From the software required to the image generator to the different display systems -- both head based and projection based -- all components of a VR system as well as practical deployment issues will be investigated. The stereo depth principle will be explained along with the different stereo methodologies available today. Aspects of a VR experience like immersion and collaboration will be explored. Other topics include the physical interface and interaction devices and the methods of manipulating a Virtual Environment by tracking users and devices.An attempt will be made to differentiate VR from pre-rendered Computer Graphics by presenting the issues concerning Real Time graphics. Finally possible future developments in the areas of Virtual Reality technology and Virtual Environments will be presented.

The evolution of Virtual Reality (VR) technology has contributed in all fields, including psychology. This evolution involves improvements in hardware and software allowing more immersive experiences. In a VR environment users can perceive the sensation of presence and feel immersed. These sensations are possible using VR devices as HMDs. Nowadays, the development of the HMDs has focused on improving their technical features to offer full immersion. In psychology, VR environments are research tools because they allow the use of new paradigms that are not possible to employ in a real environment. There are some applications for assessing spatial memory that use basic methods of HCI. However, VR systems that incorporate stereoscopy and physical movement have not yet been exploited in psychology. In this thesis, a novel VR system combining immersive, interactive and motion features was developed. This system was used for the assessment of the spatial memory and the evaluation of depth perception. For this system, a virtual maze task was designed and implemented. In this system, two different types of interaction were integrated: a locomotion-based interaction pedaling a fixed bicycle (condition1), and a stationary interaction using a gamepad (condition2). This system integrated two types of display systems: 1) The Oculus Rift; 2) A large stereo screen. Two studies were designed to determine the efficacy of the VR system using physical movement and immersion. The first study (N=89) assessed the spatial short term memory using the Oculus Rift and the two types of interaction The results showed that there were statistically significant differences between both conditions. The participants who performed the condition2 got better performance than participants who performed the condition1. However, there were no statistically significant differences in satisfaction and interaction scores between both conditions. The performance on the task correlated with the performance on other classical neuropsychological tests, revealing a verisimilitude between them. The second study (N=59) involved participants who had and who had not stereopsis. This study assessed the depth perception by comparing the two display systems. The participants performed the task using the condition2. The results showed that the different features of the display system did not influence the performance on the task between the participants with and without stereopsis. Statistically significant differences were found in favor of the HMD between the two conditions and between the two groups of participants regard to depth perception. The participants who did not have stereopsis and could not perceive the depth when they used other display systems (e.g. CAVE); however, they had the illusion of depth perception when they used the Oculus Rift. The study suggests that for the people who did not have stereopsis, the head tracking largely influences the 3D experience. The statistical results of both studies have proven that the VR system developed for this research is an appropriate tool to assess the spatial short-term memory and the depth perception. Therefore, the VR systems that combine full immersion, interaction and movement can be a helpful tool for the assessment of human cognitive processes as the memory. General conclusions from these studies are: 1) The VR technology and immersion provided by current HMDs are appropriate tools for psychological applications, in particular, the assessment of spatial short-term memory; 2) A VR system like the one presented in this thesis could be used as a tool to assess or train adults in skills related to spatial short-term memory; 3) The two types of interaction (condition1 and condition2) used for navigation within the virtual maze could be helpful to use with different collectives; 4) The Oculus Rift allows that the users without stereopsis can perceive the depth perception of 3D objects and have rich 3D experiences.

Virtual reality (VR) technology has become a growing force in entertainment, education, science, and manufacturing due to the capability of providing users with immersive experiences and natural interaction. Although common input devices such as controllers, gamepads, and trackpads have been integrated into mainstream VR systems for user-content interaction, they cannot provide users with realistic haptic feedback. Some prior work tracks and maps the physical objects into the virtual space to allow users to interact with these objects directly, which improves users’ sense of reality in the virtual environment. However, most of them use additional hardware sensors, which inevitably increases the cost. In this research, a lightweight approach is proposed to synchronize the positions and motions between physical and digital objects without any extra costs. We use the real-time captured video data from in-built cameras on a VR headset and employ feature points based algorithms to generate projections of the physical objects in the virtual world. Our approach does not rely on additional sensors but just uses components available in a VR headset. Our approach allows users to interact with target objects with their hands directly without the need for specially designed trackers, markers, and other hardware devices as used in previous work. With our approach, users can get more realistic operational feedback when interacting with corresponding virtual objects.

A virtual reality (VR) system tracks one or more objects to generate the depiction of a virtual environment from the user's vantage point. No system achieves this instantaneously: changes in the depicted virtual environment are delayed from changes in the position of the objects being tracked. In this paper, a method is proposed to quantify this time difference, the end-to-end delay of the VR system. Two light-sensing devices and two luminance gradients are used to simultaneously encode the position of one tracked object and its virtual counterpart. One light-sensing device is attached to the tracked object and it captures light from the gradient in the physical environment. The other device captures light from the gradient in the virtual environment. A measurement is obtained by moving the tracked object repetitively (by hand) across the gradient. The end-to-end delay is the asynchrony between the signals generated by the two light-sensing devices. The results collected with oscillatory movements performed at different frequencies indicate that for some VR systems, the end-to-end delay might not be constant but could vary as a function of the oscillation frequency.

Generally, a virtual reality (VR) system cannot provide the realistic sound formed by the multi-channel audio signals to a user with the stereo headphone environment. In addition, the VR system has a gap between the visual scene and the sound because it supplies the audio signal having only a constant sound scene without respect to the change of the user's position. To solve these problems, we introduce the sound scene control of binaural sound. Binaural sound is a stereo realistic sound that can be generated by convolving a 10.1 channel audio signal with a head related transfer function (HRTF) coefficients which features all the paths from the multi-channel speaker layout to the ears in free space. However, since a binaural sound is generated using a fixed multi-channel layout and HRTF coefficients, the binaural sound has a constant sound scene and cannot reflect the user's movements. So, we apply the sound scene control scheme that modifies the binaural sound to allow the user's movement in the VR system. Initially, a multichannel layout is re-created according to the user's azimuth change and the original multi-channel signal is mapped to a new ultra multi-channel layout using a constant power panning law. Secondly, the sound level of the new multichannel audio signal is controlled by the user's distance change, using the characteristics of the sound level inversely proportional to distance. Finally, the final multi-channel audio signal is convolved with the HRTF coefficients to produce a binaural sound with the controlled sound scene. As a result, the proposed realistic audio sound generation method allows the current VR system to provide true VR service without distinction between the visual scenes and sounds.