A neuro-fuzzy warning system for combating cybersickness in the elderly caused by the virtual environment on a TFT-LCD

Only a few studies in the literature have focused on the effects of age on virtual environment (VE) sickness susceptibility and even less research was carried out focusing on the elderly. In general, the elderly usually browse VEs on a thin film transistor liquid crystal display (TFT-LCD) at home or somewhere, not a head-mounted display (HMD). While the TFT-LCD is used to present VEs, this set-up does not physically enclose the user. Therefore, this study investigated the factors that contribute to cybersickness among the elderly when immersed into a VE on TFT-LCD, including exposure durations, navigation rotating speeds and angle of inclination. Participants were elderly, with an average age of 69.5 years. The results of the first experiment showed that the rate of simulator sickness questionnaire (SSQ) scores increases significantly with navigational rotating speed and duration of exposure. However, the experimental data also showed that the rate of SSQ scores does not increase with the increase in angle of inclination. In applying these findings, the neuro-fuzzy technology was used to develop a neuro-fuzzy cybersickness-warning system integrating fuzzy logic reasoning and neural network learning. The contributing factors were navigational rotating speed and duration of exposure. The results of the second experiment showed that the proposed system can efficiently determine the level of cybersickness based on the associated subjective sickness estimates and combat cybersickness due to long exposure to a VE.     

The use of virtual environments based on a modification of the computer game Quake III Arena in psychological experimenting

We investigated whether newly developed virtual 3D environments (VEs) based on a modification of the computer game Quake III Arena^® are suitable for psychological experimenting. Internal validity of data collected in VEs may be threatened due to a priori individual differences in general performance in VE navigation and in susceptibility to cybersickness. The main question was whether individual differences in performance can be diminished by means of training. Additionally, the susceptibility of different subsamples to cybersickness when moving within VEs was examined. 85 participants took part in an experiment where they had to fulfill simple tasks in three VEs. Navigation performance was measured as the time participants needed to make their way through the VEs. Differences in navigation performance between different levels of experience were diminished by training, indicating that internal validity can be obtained. A classification tree reveals that game-inexperienced female participants aged over 31 years have the highest risk of experiencing cybersickness. VEs based on modifications of computer games seem to be an extremely promising and inexpensive possibility for the administration of psychological experiments.     

Cybersickness in the presence of scene rotational movements along different axes

Compelling scene movements in a virtual reality (VR) system can cause symptoms of motion sickness (i.e., cybersickness). A within-subject experiment has been conducted to investigate the effects of scene oscillations along different axes on the level of cybersickness. Sixteen male participants were exposed to four 20-min VR simulation sessions. The four sessions used the same virtual environment but with scene oscillations along different axes, i.e., pitch, yaw, roll, or no oscillation (speed: 30 degrees/s, range: +/- 60 degrees). Verbal ratings of the level of nausea were taken at 5-min intervals during the sessions and sickness symptoms were also measured before and after the sessions using the Simulator Sickness Questionnaire (SSQ). In the presence of scene oscillation, both nausea ratings and SSQ scores increased at significantly higher rates than with no oscillation. While individual participants exhibited different susceptibilities to nausea associated with VR simulation containing scene oscillations along different rotational axes, the overall effects of axis among our group of 16 randomly selected participants were not significant. The main effects of, and interactions among, scene oscillation, duration, and participants are discussed in the paper.     

A study of cybersickness and sensory conflict theory using a motion-coupled virtual reality system

Sensory conflict theory explains that motion sickness in virtual reality (VR) systems can be caused due to the mismatch between visual and vestibular senses. This study examines whether coupling physical motions to visual stimuli in VR could reduce this discomfort. A motion-coupled VR system developed on a motion platform, providing vestibular cues to supplement visual roll from a head-mounted display (HMD), was used. Three conditions were tested: visual rotation only (stationary), visual-physical motion synchronised (synchronous), and vestibular motion with a self-referenced visual environment. Results show that when users are placed under a visual-vestibular synchronised condition, their subjective miserable score of cybersickness decreased while their comfort level of the overall experience increased. This indicates that a motion-coupled system, if integrated seamlessly in VR, could mitigate cybersickness symptoms.     

Effects of speed,complexity and stereoscopic VR cues on cybersickness examined via EEG and self-reported measures

This study evaluated the interplay between environmental cues in virtual reality (VR) and cybersickness as experienced by users of head-mounted displays (HMDs). Utilizing electroencephalogram (EEG) data and self-reported discomfort measures, the effects of three major VR cues – speed, scene complexity, and stereoscopic rendering – on cybersickness were examined, with the latter being of particular interest as it had not previously been studied explicitly in the context of VR-HMDs. Self-reported discomfort was assessed through in-VR single-item queries and post-VR simulator sickness questionnaires, accounting for both immediate and persistent cybersickness, respectively, and over three experiment sessions, accounting for the effects of accumulation. Analysis revealed connections that indicate a relationship between EEG data and the presence of cybersickness for all three cue types. Significant differences were observed in EEG relative power changes between the trials where cybersickness was and was not reported. EEG relative power changes were also linked to both immediate and persistent cybersickness, especially in the theta and gamma frequency bands. The increase in immediate discomfort with the stereoscopic rendering cues over successive sessions suggests a decrease in tolerance to these effects over time.     

Quantifying VR cybersickness using EEG

Virtual Reality - Current techniques for characterizing cybersickness (visually induced motion sickness) in virtual environments rely on qualitative questionnaires. For interactive graphics to...     

Postural stability predicts the likelihood of cybersickness in active HMD-based virtual reality

Cybersickness is common during virtual reality experiences with head-mounted displays (HMDs). Previously it has been shown that individual differences in postural activity can predict which people are more likely to experience visually-induced motion sickness. This study examined whether such predictions also generalise to the cybersickness experienced during active HMD-based virtual reality. Multisensory stimulation was generated by having participants continuously turn their heads from left to right while viewing the self-motion simulations. Real-time head tracking was then used to create ecological (‘compensated’) and non-ecological (‘inversely compensated’) head-and-display motion conditions. Ten (out of 20) participants reported feeling sick after being exposed to these self-motion simulations. Cybersickness did not differ significantly between the two compensation conditions. However, individual differences in spontaneous postural instability when standing quietly were found to predict the likelihood of subsequently experiencing cybersickness. These findings support recent proposals that postural measures can help diagnose who will benefit the most/least from HMD-based virtual reality.     

Task performance in a head-mounted display: The impacts of varying latency

The purpose of this study was to determine how latency in a head-mounted display (HMD) affects human performance. Virtual environments (VEs) are used frequently for training. However, VEs can cause simulator sickness. Prior work in our laboratory has examined the role of varying latency in simulator sickness. However, the effect of varying latency on task performance has not been examined. Subjects participated in a repeated measures study where they were exposed to two different latency conditions in an HMD: constant (70 ms) and varying (70–270 ms). During each HMD exposure, subjects used a laser pointer to repeatedly “shoot” at laser targets while accuracy and time-to-hit were recorded. Subjects scored fewer hits and took longer to hit targets in the varying latency condition. These findings indicate that individuals exposed to varying latency perform worse than individuals exposed to a lower constant latency.     

Review on cybersickness in applications and visual displays

Cybersickness is an affliction common to users of virtual environments. Similar in symptoms to motion sickness, cybersickness can result in nausea, headaches, and dizziness. With these systems becoming readily available to the general public, reports of cybersickness have increased and there is a growing concern about the safety of these systems. This review presents the current state of research methods, theories, and known aspects associated with cybersickness. Current measurements of incidence of cybersickness are questionnaires, postural sway, and physiological state. Varying effects due to display and rendering modes, such as visual display type and stereoscopic or monoscopic rendering, are compared. The known and suspected application aspects that induce cybersickness are discussed. There are numerous potential contributing application design aspects, many of which have had limited study, but field of view and navigation are strongly correlated with cybersickness. The effect of visual displays is not well understood, and application design may be of greater importance.     

Effects of dynamic field-of-view restriction on cybersickness and presence in HMD-based virtual reality

The phenomenon of cybersickness is currently hindering the mass market adoption of head-mounted display (HMD) virtual reality (VR) technologies. This study examined the effects of dynamic field-of-view (FOV) restriction on the cybersickness generated by ecological HMD-based gameplay. Forty participants were exposed to a commercially available HMD game (Marvel Powers United VR) under both unrestricted FOV and dynamic FOV restriction conditions across three sessions. Participants had their spontaneous postural instability measured before entering VR. Then, during/following each of these 10-min exposures to HMD VR, they rated their cybersickness, vection (illusory self-motion), and feelings of presence. Individual differences in spontaneous postural instability were found to predict cybersickness during HMD VR gameplay. Cybersickness severity increased steadily over the course of each VR exposure and was significantly reduced by dynamic FOV restriction. Presence also increased steadily over the course of each VR exposure and was positively correlated with vection. We conclude that: (1) postural instability can identify people who are more susceptible to cybersickness, (2) vection can increase an HMD user’s feelings of presence, and (3) dynamic FOV restriction can serve as a viable countermeasure to cybersickness.

     

Effects of navigation speed on motion sickness caused by an immersive virtual environment

This study investigated the effects of navigation speed on the level of motion sickness during and after a 30-min head-steered virtual environment. Root-mean-squares for 8 speeds in the fore-and-aft axis were 3, 4, 6, 8, 10, 24, 30, and 59 m/s. Participants were 96 Chinese men. Both the nausea and vection ratings increased significantly with speeds increasing from 3 m/s to 10 m/s. At speeds exceeding 10 m/s, the ratings stabilized. Navigation speeds were found to significantly affect the onset times of vection and nausea but did not affect their rates of increase with duration of exposure. For the various Simulator Sickness Questionnaire scores, navigation speed had a significant influence on only the oculomotor subscore. Actual or potential applications of this research include the prediction of sickness associated with simulation tours in a virtual environment at different navigation speeds.     

一个基于Web的网络虚拟现实系统的设计与实现

虚拟现实技术发展很快,有广泛的工业和商业应用。网络虚拟现实技术已越来越为工业制造业所关注,虚拟制造环境(VME)的一个主要用途是在线可视化和对3D信息的协作控制,这需要实时数据传输的支持。为了满足基于Internet的VE通信需求,特别是为满足虚拟制造和协作设计和控制,该文设计并实现了一个支持网络虚拟设计和制造的网络虚拟现实系统,此系统用MMS协议实现VE通信,并将工业控制服务集成于基于Internet的虚拟环境中。     

Effects of virtual environment platforms on emotional responses

The goal of the current study was to investigate the effects of different virtual environment (VE) technologies (i.e., desktop, head mounted display, or fully immersive platforms) on emotional arousal and task performance. Fifty-three participants were recruited from a college population. Reactivity to stressful VEs was examined in three VE systems from desktop to high-end fully immersive systems. The experiment was a 3 (desktop system, head mounted display, and six wall system) × 2 (high- and low-stressful VE) within subject design, with self-reported emotional arousal and valence, skin conductance, task performance, presence, and simulator sickness examined as dependent variables. Replicating previous studies, the fully immersive system induced the highest sense of presence and the head mounted display system elicited the highest amount of simulator sickness. Extending previous studies, the results demonstrated that VE platforms were associated with different patterns in emotional responses and task performance. Our findings suggest that different VE systems may be appropriate for different scientific purposes when studying stress reactivity using emotionally evocative tasks.     

基于场景语义的3D交互体系结构

借鉴真实世界的认知心理学原理,将虚拟场景的可视表达和语义信息结合起来共同服务于用户的交互过程,多种3D交互技术被融合在一个统一的交互框架内,使复杂虚拟环境中的3D用户界面更容易被用户理解和使用.通过增强场景图的语义处理能力,建立支持高层语义的3D用户界面体系结构,3D交互系统不仅在几何层上而且还能在语义层上支持交互任务的执行.最后介绍了一个应用实例.     

Cybersickness during VR gaming undermines game enjoyment: A mediation model

Recent advances in virtual reality (VR) technology have ushered in a new era of VR gaming. While VR gaming experience represents a burgeoning area of research within human-computer interaction circles, the role of cybersickness, physiological repercussions of VR exposure to users characterized by a multitude of symptoms, such as nausea, lightheadedness, and dizziness, in the effect of VR gaming on game enjoyment remains understudied. In two experiments, the current study proposed and tested a causal mediation model in which the effect of VR gaming on game enjoyment was mediated by the level of cybersickness experienced during the gameplay. Results from both experiments supported the proposed model and showed that increased cybersickness levels during VR gaming led to decreases in game enjoyment, indicating that cybersickness experienced during VR gaming undermines the enjoyment of the gaming experience. Results also revealed that compared to traditional desktop gaming, VR gaming invoked greater levels of cybersickness, but VR gaming did not lead to greater levels of game enjoyment. When the effect of cybersickness on game enjoyment was statistically removed, however, VR gaming was found to be more enjoyable. The current experiments provide preliminary evidence that cybersickness may hinder the enjoyment of VR gaming experience.     

Ndebele painting in VR

The Ndebele tribe of southern Africa consists of four subtribes. The Ndzundza is the only Ndebele group practising the decorative arts of painting and beadwork. The craft of producing striking, colourful and geometrical artwork has become their most distinctive feature. The Ndebele wall painting's work and richness provided the inspiration for our project. We created a virtual environment (VE) and an interaction method that facilitates the creation, painting and mapping of these paintings on different 2D and 3D surfaces. Designing tools for painting in VEs presents many challenges. We must support design without restricting the artist's creative process. Commercially available tools mainly work in a 2D environment and use specialized interaction devices. Design tools in VEs use a mixture of 2D and 3D interaction devices and metaphors and mainly target 3D modeling for a variety of application areas. In our project-a research interface for Ndebele wall painting in a VE-we focus on the specific process of wall painting and keep our interaction metaphors as close as possible to the real wall-painting process, At the same time, the project takes advantage of the many possibilities that a VE can offer in terms of production speed and mapping on to different surfaces, among others     

Effects of postural stability,active control,exposure duration and repeated exposures on HMD induced cybersickness

Cybersickness is common during head-mounted display (HMD) based virtual reality. This study examined whether it is possible to: (1) identify people who are more susceptible to this cybersickness; and (2) find general ways to reduce its occurrence and severity. Our participants were exposed to HMD-based virtual reality four times over two different days (using “Freedom Locomotion VR”). During these 10-min trials, participants were either free-standing or posturally restrained as they actively controlled or passively viewed their locomotion through the virtual environment. Cybersickness was found to increase steadily over time during each exposure. While this cybersickness was markedly reduced on day 2 (compared to day 1), it was not significantly altered by either the use of postural restraints or active locomotion control. However, the sick and well participants in our study were found to differ in terms of their spontaneous postural activity (before they entered virtual reality). We found that the participants who experienced stronger vection also tended to report more severe cybersickness in this study. These findings suggest that we should be able to identify people who are more susceptible to cybersickness and help them become more resistant to it (via repeated exposures to HMD-based virtual reality).     

Spatial and attentional aftereffects of virtual reality and relations to cybersickness

Virtual Reality - Cybersickness describes the nausea and discomfort that frequently emerges upon exposure to a virtual reality (VR) environment. The extent to which cybersickness leads to temporary...     

Exploiting perceptual limitations and illusions to support walking through virtual environments in confined physical spaces

Head-mounted displays (HMDs) allow users to immerse in a virtual environment (VE) in which the user’s viewpoint can be changed according to the tracked movements in real space. Because the size of the virtual world often differs from the size of the tracked lab space, a straightforward implementation of omni-directional and unlimited walking is not generally possible. In this article we review and discuss a set of techniques that use known perceptual limitations and illusions to support seemingly natural walking through a large virtual environment in a confined lab space. The concept behind these techniques is called redirected walking. With redirected walking, users are guided unnoticeably on a physical path that differs from the path the user perceives in the virtual world by manipulating the transformations from real to virtual movements. For example, virtually rotating the view in the HMD to one side with every step causes the user to unknowingly compensate by walking a circular arc in the opposite direction, while having the illusion of walking on a straight trajectory. We describe a number of perceptual illusions that exploit perceptual limitations of motion detectors to manipulate the user’s perception of the speed and direction of his motion. We describe how gains of locomotor speed, rotation, and curvature can gradually alter the physical trajectory without the users observing any discrepancy, and discuss studies that investigated perceptual thresholds for these manipulations. We discuss the potential of self-motion illusions to shift or widen the applicable ranges for gain manipulations and to compensate for over- or underestimations of speed or travel distance in VEs. Finally, we identify a number of key issues for future research on this topic.     

Realization of reconfigurable virtual environments for virtual testing

1 Introduction The scalability of virtual environments (VEs) that allow users to change and modify their contents and context depending on application requirements has been a de facto feature of virtual reality technology. Engineering uses such as virtual testing and exper- imenting applications demand VEs to be highly or fully reconfigurable. In reality, however, satisfactory reconfiguration of a virtual environment is yet to be achieved, due to the high accuracy of spatial data in- put and…