Monte-Carlo Redirected Walking: Gain Selection Through Simulated Walks.

We present Monte-Carlo Redirected Walking (MCRDW), a gain selection algorithm for redirected walking. MCRDW applies the Monte-Carlo method to redirected walking by simulating a large number of simple virtual walks, then inversely applying redirection to the virtual paths. Different gain levels and directions are applied, producing differing physical paths. Each physical path is scored and the results used to select the best gain level and direction. We provide a simple example implementation and a simulation-based study for validation. In our study, when compared with the next best technique, MCRDW reduced incidence of boundary collisions by over 50% while reducing total rotation and position gain.

Metameric Inpainting for Image Warping.

Image-warping, a per-pixel deformation of one image into another, is an essential component in immersive visual experiences such as virtual reality or augmented reality. The primary issue with image warping is disocclusions, where occluded (and hence unknown) parts of the input image would be required to compose the output image. We introduce a new image warping method, Metameric image inpainting - an approach for hole-filling in real-time with foundations in human visual perception. Our method estimates image feature statistics of disoccluded regions from their neighbours. These statistics are inpainted and used to synthesise visuals in real-time that are less noticeable to study participants, particularly in peripheral vision. Our method offers speed improvements over the standard structured image inpainting methods while improving realism over colour-based inpainting such as push-pull. Hence, our work paves the way towards future applications such as depth image-based rendering, 6-DoF 360 rendering, and remote render-streaming.

SafeSpace: what is the feasibility and acceptability of a codesigned virtual reality intervention, incorporating compassionate mind training, to support people undergoing cancer treatment in a clinical setting?

OBJECTIVES: The SafeSpace study codesigned and tested a virtual reality (VR) intervention, incorporating relaxation and compassionate mind training to determine acceptability/feasibility in an oncology setting and evaluate impact on physical/psychological well-being and quality of life. DESIGN: A two-phase study. Phase I determined key characteristics using an experienced-based codesign approach. Phase II evaluated the intervention using various measures and qualitative interviews in a mixed methods approach. Descriptive statistics were used to analyse measures data and framework analysis to analyse interviews. SETTING: A specialist cancer centre, UK. PARTICIPANTS: 11 in phase I and 21 in phase II. Participants were in cancer treatment, recovery or palliative care. PRIMARY AND SECONDARY OUTCOME: Primary outcome: acceptability of the intervention, assessed by >60% uptake of three sessions. SECONDARY OUTCOMES: impact on psychological well-being using EQ-5D/QLQ-C30, Profile of Mood Scale, Warwick and Edinburgh Mental Well-being Scale, Depression and Anxiety Severity Scale 21, Self-Compassion Scale, Acceptance and Action Questionnaire and a locally developed questionnaire to capture self-compassion post use. Physiological impact was assessed by change in heart rate (HR)/HR variability and electrodermal activity (EDA). RESULTS: Twenty participants (mean age=48.7 years; SD=16.87); 65% (n=13) completed three sessions. Mental well-being improved following each use and from baseline to after session 3 (VR 1-z=2.846, p≤0.01; VR 2-z=2.501, p≤0.01; VR 3-z=2.492, p≤0.01). There was statistically significant difference in mean scores for EDA at mid-session and post session compared with pre session (F (1.658, 4.973)=13.364, p<0.05). There was statistically significant reduction in stress levels from baseline to post session 3. Participants found the intervention acceptable and highlighted areas for development. CONCLUSION: The intervention is acceptable and feasible and has shown positive effects on mental well-being/stress in the oncology setting. Larger studies are needed to confirm findings.

Teaching Social Virtual Reality With Ubiq.

We share our experiences of teaching virtual reality with Ubiq, an open-source system for building social virtual reality (VR). VR as a subject touches on many areas, including perception, human-computer interaction, and psychology. In our VE module, we consider all aspects of VR. In recent years, networked VR, and in particular social VR, has become increasingly relevant, at the same time as demand for online and hybrid teaching has increased. Commercial social virtual reality systems have proliferated, but for a number of reasons, this has not resulted in systems any more suitable for research and teaching. As a result we created Ubiq, a system for building social VR applications designed first for research and teaching. In this article, we describe how Ubiq came to be, and our experiences of using it in our virtual environments module over the last two years.

Consensus Based Networking of Distributed Virtual Environments.

Distributed virtual environments (DVEs) are challenging to create as the goals of consistency and responsiveness become contradictory under increasing latency. DVEs have been considered as both distributed transactional databases and force-reflection systems. Both are good approaches, but they do have drawbacks. Transactional systems do not support Level 3 (L3) collaboration: manipulating the same degree-of-freedom at the same time. Force-reflection requires a client-server architecture and stabilisation techniques. With Consensus Based Networking (CBN), we suggest DVEs be considered as a distributed data-fusion problem. Many simulations run in parallel and exchange their states, with remote states integrated with continous authority. Over time the exchanges average out local differences, performing a distribued-average of a consistent, shared state. CBN aims to build simulations that are highly responsive, but consistent enough for use cases such as the piano-movers problem. CBN's support for heterogeneous nodes can transparently couple different input methods, avoid the requirement of determinism, and provide more options for personal control over the shared experience. Our work is early, however we demonstrate many successes, including L3 collaboration in room-scale VR, 1000's of interacting objects, complex configurations such as stacking, and transparent coupling of haptic devices. These have been shown before, but each with a different technique; CBN supports them all within a single, unified system.

A mechatronic shape display based on auxetic materials.

Shape displays enable people to touch simulated surfaces. A common architecture of such devices uses a mechatronic pin-matrix. Besides their complexity and high cost, these matrix displays suffer from sharp edges due to the discreet representation which reduces their ability to render a large continuous surface when sliding the hand. We propose using an engineered auxetic material actuated by a smaller number of motors. The material bends in multiple directions, feeling smooth and rigid to touch. A prototype implementation uses nine actuators on a 220 mm square section of material. It can display a range of surface curvatures under the palm of a user without aliased edges. In this work we use an auxetic skeleton to provide rigidity on a soft material and demonstrate the potential of this class of surface through user experiments.

Directions for 3D User Interface Research from Consumer VR Games.

With the continuing development of affordable immersive virtual reality (VR) systems, there is now a growing market for consumer content. The current form of consumer systems is not dissimilar to the lab-based VR systems of the past 30 years: the primary input mechanism is a head-tracked display and one or two tracked hands with buttons and joysticks on hand-held controllers. Over those 30 years, a very diverse academic literature has emerged that covers design and ergonomics of 3D user interfaces (3DUIs). However, the growing consumer market has engaged a very broad range of creatives that have built a very diverse set of designs. Sometimes these designs adopt findings from the academic literature, but other times they experiment with completely novel or counter-intuitive mechanisms. In this paper and its online adjunct, we report on novel 3DUI design patterns that are interesting from both design and research perspectives: they are highly novel, potentially broadly re-usable and/or suggest interesting avenues for evaluation. The supplemental material, which is a living document, is a crowd-sourced repository of interesting patterns. This paper is a curated snapshot of those patterns that were considered to be the most fruitful for further elaboration.

Quality of Service Impact on Edge Physics Simulations for VR.

Mobile HMDs must sacrifice compute performance to achieve ergonomic and power requirements for extended use. Consequently, applications must either reduce rendering and simulation complexity - along with the richness of the experience - or offload complexity to a server. Within the context of edge-computing, a popular way to do this is through render streaming. Render streaming has been demonstrated for desktops and consoles. It has also been explored for HMDs. However, the latency requirements of head tracking make this application much more challenging. While mobile GPUs are not yet as capable as their desktop counterparts, we note that they are becoming more powerful and efficient. With the hard requirements of VR, it is worth continuing to investigate what schemes could optimally balance load, latency and quality. We propose an alternative we call edge-physics: streaming at the scene-graph level from a simulation running on edge-resources, analogous to cluster rendering. Scene streaming is not only straightforward, but compute and bandwidth efficient. The most demanding loops run locally. Jobs that hit the power-wall of mobile CPUs are off-loaded, while improving GPUs are leveraged, maximising compute utilisation. In this paper we create a prototypical implementation and evaluate its potential in terms of fidelity, bandwidth and performance. We show that an effective system which maintains high consistencies on typical edge-links can be easily built, but that some traditional concepts are not applicable, and a better understanding of the perception of motion is required to evaluate such a system comprehensively.

Willingness of volunteers from Canadian Blood Service's Stem Cell Registry to donate blood, marrow, and other tissues for regenerative therapy.

BACKGROUND: As research surrounding cell-based regenerative therapy advances toward human trials, greater demand for cell products sourced from healthy donors will arise. The extent to which volunteers in Canadian Blood Services Stem Cell Registry would be willing to donate cells to support regenerative therapy is not known and warrants exploration. METHODS: We conducted a Web-based survey to assess factors that would influence donor willingness to donate various tissues (blood, skin, fat, and bone marrow) for regenerative therapy. The survey was provided to 15,000 randomly selected donors who registered between 2013 and 2018. Data from the 1118 respondents were analyzed. RESULTS: Despite a mixed degree of familiarity with regenerative medicine, potential donors were very supportive of donating for direct patient care and for research, and increasing their familiarity by reading a brief paragraph of information on regenerative medicine increased willingness to donate. Canadian Blood Services' stem cell registrants greatly preferred supporting nonprofit groups in research and development in comparison to entities that represent profit-seeking industry involvement. The most important factors influencing donor willingness to donate were having an impact on patients, safety of donation, advancing knowledge in regenerative medicine, a manageable time commitment, and tolerable pain that could be managed. Donors were most willing to donate blood and had mixed responses to donating other tissue types. CONCLUSIONS: Adult volunteers from a national stem cell registry are willing to support donation of biospecimens for regenerative therapy.

Using Facial Animation to Increase the Enfacement Illusion and Avatar Self-Identification.

Through avatar embodiment in Virtual Reality (VR) we can achieve the illusion that an avatar is substituting our body: the avatar moves as we move and we see it from a first person perspective. However, self-identification, the process of identifying a representation as being oneself, poses new challenges because a key determinant is that we see and have agency in our own face. Providing control over the face is hard with current HMD technologies because face tracking is either cumbersome or error prone. However, limited animation is easily achieved based on speaking. We investigate the level of avatar enfacement, that is believing that a picture of a face is one's own face, with three levels of facial animation: (i) one in which the facial expressions of the avatars are static, (ii) one in which we implement lip-sync motion and (iii) one in which the avatar presents lip-sync plus additional facial animations, with blinks, designed by a professional animator. We measure self-identification using a face morphing tool that morphs from the face of the participant to the face of a gender matched avatar. We find that self-identification on avatars can be increased through pre-baked animations even when these are not photorealistic nor look like the participant.

Real-Time Collision Detection for Deformable Characters with Radial Fields.

Many techniques facilitate real-time collision detection against complex models. These typically work by pre-computing information about the spatial distribution of geometry into a form that can be quickly queried. When models deform though, expensive pre-computations are impractical. We present radial fields: a variant of distance fields parameterised in cylindrical space, rather than Cartesian space. This 2D parameterisation significantly reduces the memory and computation requirements of the field, while introducing minimal overhead in collision detection tests. The interior of the mesh is defined implicitly for the entire domain. Importantly, it maps well to the hardware rasteriser of the GPU. Radial fields are much more application-specific than traditional distance fields. For these applications - such as collision detection with articulated characters-however, the benefits are substantial.

How Foot Tracking Matters: The Impact of an Animated Self-Avatar on Interaction, Embodiment and Presence in Shared Virtual Environments.

The use of a self-avatar representation in head-mounted displays has been shown to have important effects on user behavior. However, relatively few studies focus on feet and legs. We implemented a shared virtual reality for consumer virtual reality systems where each user could be represented by a gender-matched self-avatar controlled by multiple trackers. The self-avatar allowed users to see their feet, legs and part of their torso when they looked down. We implemented an experiment where participants worked together to solve jigsaw puzzles. Participants experienced either no-avatar, a self-avatar with floating feet, or a self-avatar with tracked feet, in a between-subjects manipulation. First, we found that participants could solve the puzzle more quickly with self-avatars than without self-avatars; but there was no significant difference between the latter two conditions, solely on task completion time. Second, we found participants with tracked feet placed their feet statistically significantly closer to obstacles than participants with floating feet, whereas participants who did not have a self-avatar usually ignored obstacles. Our post-experience questionnaire results confirmed that the use of a self-avatar has important effects on presence and interaction. Together the results show that although the impact of animated legs might be subtle, it does change how users behave around obstacles. This could have important implications for the design of virtual spaces for applications such as training or behavioral analysis.

The Effect of Transition Type in Multi-View 360° Media.

360° images and video have become extremely popular formats for immersive displays, due in large part to the technical ease of content production. While many experiences use a single camera viewpoint, an increasing number of experiences use multiple camera locations. In such multi-view 360° media (MV360M) systems, a visual effect is required when the user transitions from one camera location to another. This effect can take several forms, such as a cut or an image-based warp, and the choice of effect may impact many aspects of the experience, including issues related to enjoyment and scene understanding. To investigate the effect of transition types on immersive MV360M experiences, a repeated-measures experiment was conducted with 31 participants. Wearing a head-mounted display, participants explored four static scenes, for which multiple 360° images and a reconstructed 3D model were available. Three transition types were examined: teleport, a linear move through a 3D model of the scene, and an image-based transition using a Möbius transformation. The metrics investigated included spatial awareness, users' movement profiles, transition preference and the subjective feeling of moving through the space. Results indicate that there was no significant difference between transition types in terms of spatial awareness, while significant differences were found for users' movement profiles, with participants taking 1.6 seconds longer to select their next location following a teleport transition. The model and Möbius transitions were significantly better in terms of creating the feeling of moving through the space. Preference was also significantly different, with model and teleport transitions being preferred over Möbius transitions. Our results indicate that trade-offs between transitions will require content creators to think carefully about what aspects they consider to be most important when producing MV360M experiences.

A Comparison of Virtual and Physical Training Transfer of Bimanual Assembly Tasks.

As we explore the use of consumer virtual reality technology for training applications, there is a need to evaluate its validity compared to more traditional training formats. In this paper, we present a study that compares the effectiveness of virtual training and physical training for teaching a bimanual assembly task. In a between-subjects experiment, 60 participants were trained to solve three 3D burr puzzles in one of six conditions comprised of virtual and physical training elements. In the four physical conditions, training was delivered via paper- and video-based instructions, with or without the physical puzzles to practice with. In the two virtual conditions, participants learnt to assemble the puzzles in an interactive virtual environment, with or without 3D animations showing the assembly process. After training, we conducted immediate tests in which participants were asked to solve a physical version of the puzzles. We measured performance through success rates and assembly completion testing times. We also measured training times as well as subjective ratings on several aspects of the experience. Our results show that the performance of virtually trained participants was promising. A statistically significant difference was not found between virtual training with animated instructions and the best performing physical condition (in which physical blocks were available during training) for the last and most complex puzzle in terms of success rates and testing times. Performance in retention tests two weeks after training was generally not as good as expected for all experimental conditions. We discuss the implications of the results and highlight the validity of virtual reality systems in training.

"We Wait"-The Impact of Character Responsiveness and Self Embodiment on Presence and Interest in an Immersive News Experience.

A virtual reality scenario called "We Wait" gives people an immersive experience of the plight of refugees waiting to be picked up by a boat on a shore in Turkey to be illegally taken to Europe, crossing a dangerous stretch of sea. This was based on BBC news reporting of the refugee situation, but deliberately depicted as an animation with cartoon-like characters representing the refugees. Of interest was the level of presence that might be experienced by participants and the extent to which the scenario might prompt participants to follow-up further information about the refugee crisis. By presence we refer to both Place Illusion, the illusion of being in the rendered space, and Plausibility, the illusion that the unfolding events were really happening. The follow-up was assessed by whether and when participants accessed a web page that contained further information about the refugee crisis after the experiment. Two factors were considered in a balanced between-groups design with 32 participants. The Responsiveness factor was either "None" or "Look at." In the first the virtual characters in the scenario never responded to actions of the participant, and in the second they would occasionally look at the participant after the participant looked at them. The second factor was Embodiment, which was either "No Body" or "Body." In the No Body condition participants had no virtual body, and in the Body condition they would see a virtual body spatially congruent with their own if they looked down toward themselves. The virtual body was animated by the head tracking move the upper body. The results showed that the major factor positively contributing to presence was Responsiveness ("Look at"), and that Embodiment ("Body") may have contributed but to a lesser extent. There were important differences between men and woman in the degree of follow-up, with men more likely to do so than women. The experiment shows that adding in some simple responses in an immersive journalism scenario, where the characters acknowledge the presence of the participant through gaze, can enhance the degree of presence felt by the participants.

The impact of self-avatars on trust and collaboration in shared virtual environments.

A self-avatar is known to have a potentially significant impact on the user's experience of the immersive content but it can also affect how users interact with each other in a shared virtual environment (SVE). We implemented an SVE for a consumer virtual reality system where each user's body could be represented by a jointed self-avatar that was dynamically controlled by head and hand controllers. We investigated the impact of a self-avatar on collaborative outcomes such as completion time and trust formation during competitive and cooperative tasks. We used two different embodiment levels: no self-avatar and self-avatar, and compared these to an in-person face to face version of the tasks. We found that participants could finish the task more quickly when they cooperated than when they competed, for both the self-avatar condition and the face to face condition, but not for the no self-avatar condition. In terms of trust formation, both the self-avatar condition and the face to face condition led to higher scores than the no self-avatar condition; however, collaboration style had no significant effect on trust built between partners. The results are further evidence of the importance of a self-avatar representation in immersive virtual reality.

From urban planning and emergency training to Pokémon Go: applications of virtual reality GIS (VRGIS) and augmented reality GIS (ARGIS) in personal, public and environmental health.

The latest generation of virtual and mixed reality hardware has rekindled interest in virtual reality GIS (VRGIS) and augmented reality GIS (ARGIS) applications in health, and opened up new and exciting opportunities and possibilities for using these technologies in the personal and public health arenas. From smart urban planning and emergency training to Pokémon Go, this article offers a snapshot of some of the most remarkable VRGIS and ARGIS solutions for tackling public and environmental health problems, and bringing about safer and healthier living options to individuals and communities. The article also covers the main technical foundations and issues underpinning these solutions.

Efficient Hybrid Image Warping for High Frame-Rate Stereoscopic Rendering.

Modern virtual reality simulations require a constant high-frame rate from the rendering engine. They may also require very low latency and stereo images. Previous rendering engines for virtual reality applications have exploited spatial and temporal coherence by using image-warping to re-use previous frames or to render a stereo pair at lower cost than running the full render pipeline twice. However these previous approaches have shown artifacts or have not scaled well with image size. We present a new image-warping algorithm that has several novel contributions: an adaptive grid generation algorithm for proxy geometry for image warping; a low-pass hole-filling algorithm to address un-occlusion; and support for transparent surfaces by efficiently ray casting transparent fragments stored in per-pixel linked lists of an A-Buffer. We evaluate our algorithm with a variety of challenging test cases. The results show that it achieves better quality image-warping than state-of-the-art techniques and that it can support transparent surfaces effectively. Finally, we show that our algorithm can achieve image warping at rates suitable for practical use in a variety of applications on modern virtual reality equipment.

The Effects of Low Latency on Pointing and Steering Tasks.

Latency is detrimental to interactive systems, especially pseudo-physical systems that emulate real-world behaviour. It prevents users from making quick corrections to their movement, and causes their experience to deviate from their expectations. Latency is a result of the processing and transport delays inherent in current computer systems. As such, while a number of studies have hypothesized that any latency will have a degrading effect, few have been able to test this for latencies less than ∼ 50 ms. In this study we investigate the effects of latency on pointing and steering tasks. We design an apparatus with a latency lower than typical interactive systems, using it to perform interaction tasks based on Fitts's law and the Steering law. We find evidence that latency begins to affect performance at ∼ 16 ms, and that the effect is non-linear. Further, we find latency does not affect the various components of an aiming motion equally. We propose a three stage characterisation of pointing movements with each stage affected independently by latency. We suggest that understanding how users execute movement is essential for studying latency at low levels, as high level metrics such as total movement time may be misleading.

Construction and Evaluation of an Ultra Low Latency Frameless Renderer for VR.

Latency - the delay between a user's action and the response to this action - is known to be detrimental to virtual reality. Latency is typically considered to be a discrete value characterising a delay, constant in time and space - but this characterisation is incomplete. Latency changes across the display during scan-out, and how it does so is dependent on the rendering approach used. In this study, we present an ultra-low latency real-time ray-casting renderer for virtual reality, implemented on an FPGA. Our renderer has a latency of ~1 ms from 'tracker to pixel'. Its frameless nature means that the region of the display with the lowest latency immediately follows the scan-beam. This is in contrast to frame-based systems such as those using typical GPUs, for which the latency increases as scan-out proceeds. Using a series of high and low speed videos of our system in use, we confirm its latency of ~1 ms. We examine how the renderer performs when driving a traditional sequential scan-out display on a readily available HMO, the Oculus Rift OK2. We contrast this with an equivalent apparatus built using a GPU. Using captured human head motion and a set of image quality measures, we assess the ability of these systems to faithfully recreate the stimuli of an ideal virtual reality system - one with a zero latency tracker, renderer and display running at 1 kHz. Finally, we examine the results of these quality measures, and how each rendering approach is affected by velocity of movement and display persistence. We find that our system, with a lower average latency, can more faithfully draw what the ideal virtual reality system would. Further, we find that with low display persistence, the sensitivity to velocity of both systems is lowered, but that it is much lower for ours.