Within the virtual reality (VR) research community, there have been several efforts to develop questionnaires with the aim of better understanding the sense of presence. Despite having numerous surveys, the community does not have a questionnaire that informs which components of a VR application contributed to the sense of presence. Furthermore, previous literature notes the absence of consensus on which questionnaire or questions should be used. Therefore, we conducted a Delphi study, engaging presence experts to establish a consensus on the most important presence questions and their respective verbiage. We then conducted a validation study with an exploratory factor analysis (EFA). The efforts between our two studies led to the creation of the Fidelity-based Presence Scale (FPS). With our consensus-driven approach and fidelity-based factoring, we hope the FPS will enable better communication within the research community and yield important future results regarding the relationship between VR system fidelity and presence.

As of IEEE VR 2023, there have been 30 installments of the IEEE Virtual Reality conference (VR) or its predecessor, the Virtual Reality Annual International Symposium (VRAIS). As such, it seems an opportune time to reflect on the intellectual history of the conference, and by extension, the VR research community. This article uses scientometric techniques to undertake such an intellectual history, using co-word analysis and citation analysis to identify core themes and trends in VR research over time. We identify the papers that have stood the test of time, the most esteemed authors and researchers in the IEEE VR community, and the topics that have shaped our field to date.

In this abstract, we discuss the demand for replication and extension efforts related to two seminal studies focused on virtual reality (VR) locomotion interfaces, initially centered around a VR implementation of the Visual Cliff, often referred to as Virtual Pit. The original experiments by Slater et al. (1995) and Usoh et al. (1999) compared different locomotion methods, including Real Walking, Walking-in-Place, and Flying/Steering, with a focus on presence and ease of use. We discuss the importance of these studies for the field, motivate replication efforts focused on these studies, discuss potential confounding factors, and present considerations for a concerted effort to reproduce the findings with state-of-the-art VR systems and measures, extensions to locomotion methods like Teleportation, and means to support future replications and extensions.

Introduction: Generalized anxiety disorder (GAD) is a chronic uncontrollable excessive anxiety towards a variety of topics. It is one of the most prevalent anxiety diseases, affecting approximately 6% worldwide. Virtual reality (VR) based interventions have received much attention from researchers for the management of mental health problems. This systematic review was conducted to assess the effects of immersive virtual reality techniques and non-immersive techniques in treating patients with GAD.Methods: An extensive systematic literature review was implemented, from inception up to 9 July 2021. Comparative clinical studies that assessed the outcomes of VRT in patients with GAD were included for meta-analysis. Single arm studies were included for systematic review only.Results: A total of six articles with 239 participants with GAD were included in systematic review. The mean age of the included participants ranged from 38.33 to 59.87 years. There was no statistically significant difference between VRT and control groups regarding the anxiety levels (SMD 0.01; 95%CI −0.52, 0.54; P = 0.97), mean depression scores (SMD 1.34; 95%CI −0.80, 3.49; P = 0.22), PSWQ (MD −4.26; 95%CI −10.93, 2.40; P = 0.21), and discomfort status (MD −1.41; 95%CI −3.86, 1.05; P = 0.22).Conclusions: VR improved relatively the manifestations of GAD, reflecting on the patient's quality of life. However, the existing evidence is inconclusive to support the superiority of VR as a substitute for traditional therapies.

Healthcare systems and services are rapidly transitioning towards a patient-centred care approach. As an allied health profession that is highly individualised, physiotherapy, requires technological innovations to advance into this space. Virtual Reality (VR) technologies have been explored and applied successfully towards achieving this transition, specifically in single-player and multi-player gaming configurations. However, most VR games are not customised to the individuals and not appropriate for the rehabilitation of patients with unique needs. Given the large volumes of data generated by the patient during an engagement with a VR game, Artificial Intelligence (AI) can be leveraged to deliver personalised physiotherapy rehabilitation. This is a work-in-progress paper that presents the design and development of a framework for personalised physiotherapy rehabilitation using AI and VR, in the setting of a single-player VR game. The completed framework will be trialled in a public hospital setting to evaluate its effectiveness in providing patient-centred physiotherapy rehabilitation for diverse patient cohorts.

As virtual reality (VR) technology becomes cheaper, higher-quality, and more widely available, it is seeing increasing use in a variety of applications including cultural heritage, real estate, and architecture. A common goal for all these applications is a compelling virtual recreation of a real place. Despite this, there has been very little research into how users perceive and experience such replicated spaces. This article reports the results from a series of three user studies investigating this topic. Results include that the scale of the room and large objects in it are most important for users to perceive the room as real and that non-physical behaviors such as objects floating in air are readily noticeable and have a negative effect even when the errors are small in scale.

Task-irrelevant distractors affect visuo-motor control for target acquisition and studying such effects has already received much attention in human-computer interaction. However, there has been little research into distractor effects on crossing-based interaction. We thus conducted an empirical study on pen-based interfaces to investigate six crossing tasks with distractor interference in comparison to two tasks without it. The six distractor-related tasks differed in movement precision constraint (directional/amplitude), target size, target distance, distractor location and target-distractor spacing. We also developed and experimentally validated six quantitative models for the six tasks. Our results show that crossing targets with distractors had longer average times and similar accuracy than that without distractors. The effects of distractors varied depending on distractor location, target-distractor spacing and movement precision constraint. When spacing is smaller than 11.27 mm, crossing tasks with distractor interference can be regarded as pointing tasks or a combination of pointing and crossing tasks, which could be better fitted with our proposed models than Fitts’ law. According to these results, we provide practical implications to crossing-based user interface design.

Presence has been studied in the context of virtual environments for nearly thirty years, but the field has yet to reach consensus on even basic issues of definition and measurement, and there are many open research questions. We gather many of these open research questions and systematically group them according to what we believe are five key constructs that inform user experience in virtual environments: immersion, coherence, Place Illusion, Plausibility Illusion, and presence. We also report on the design and results of a study that investigated the effects of immersion and coherence on user experience in a stressful virtual visual cliff environment. In this article, each participant experienced a given VE in one of four conditions chosen from a 2x2 design: high or low levels of immersion and high or low levels of coherence. We collected both questionnaire-based and physiological metrics. Several existing presence questionnaires could not reliably distinguish the effects of immersion from those of coherence. They did, however, indicate that high levels of both together result in higher presence, compared any of the other three conditions. This suggests that "breaks in PI" and "breaks in Psi" belong to a broader category of "breaks in experience," any of which result in a degraded user experience. Participants' heart rates responded markedly differently in the two coherence conditions; no such difference was observed across the immersion conditions. This indicates that a VE that exhibits unusual or confusing behavior can cause stress in a user that affects physiological responses, and that one must take care to eliminate such confusing behaviors if one is using physiological measurement as a proxy for subjective experience in a VE.

Observing eye movement is a direct way to analyse human’s attention. Eye movement patterns in normal environment have been widely investigated. In virtual reality (VR) environment, previous studies of eye movement patterns are mainly based on content-unrelated influential factors. Considering this issue, in this paper, a novel content-related factor is studied. One crucial kind of region of interest (ROI), namely vision-penetrable entrance, is chosen to analyse eye movement pattern differences. The results suggest that users show more interest in vision-penetrable entrances than in other regions. Furthermore, this kind of difference is identified as higher average density of fixation. As far as we know, this paper is the first attempt to study specific types of ROI in virtual reality environments. The method utilised in this paper can be applied in other ROI analysis.

We report on the design and results of two experiments investigating Slater's Place Illusion (PI) and Plausibility Illusion (Psi) in a virtual visual cliff environment. PI (the illusion of being in a place) and Psi (the illusion that the depicted events are actually happening) were proposed by Slater as orthogonal components of virtual experience which contribute to realistic response in a VE. To that end, we identified characteristics of a virtual reality experience that we expected to influence one or the other of PI and Psi. We designed two experiments in which each participant experienced a given VE in one of four conditions chosen from a 2×2 design: high or low levels of PI-eliciting characteristics (that is, immersion) and high or low levels of Psi-eliciting characteristics. Following Skarbez, we use the term "coherence" for those characteristics which contribute to Psi, parallel to the use of "immersion" for characteristics that contribute to PI. We collected both questionnaire-based and physiological metrics. Several existing presence questionnaires could not reliably distinguish the effects of PI from those of Psi. They did, however, indicate that high levels of PI-eliciting characteristics and Psi-eliciting characteristics together result in higher presence, compared any of the other three conditions. This suggests that "breaks in PI" and "breaks in Psi" belong to a broader category of "breaks in experience," any of which result in a degraded user experience. Participants' heart rates, however, responded markedly differently in the two Psi conditions; no such difference was observed across the PI conditions. This indicates that a VE that exhibits unusual or confusing behavior can cause stress in a user that affects physiological responses, and that one must take care to eliminate such confusing behaviors if one is using physiological measurement as a proxy for subjective experience in a VE.

We report on the design and results of an experiment investigating Slater's Place Illusion (PI) and Plausibility Illusion (Psi) in a virtual visual cliff environment. Existing presence questionnaires could not reliably distinguish the effects of PI from those of Psi. They did, however, indicate that high levels of PI-eliciting characteristics and Psi-eliciting characteristics together result in higher presence, compared to any of the other three conditions. Also, participants' heart rates responded markedly differently in the two Psi conditions; no such difference was observed across the PI conditions.

We discuss the design and results of an experiment investigating Plausibility Illusion in virtual human (VH) interactions, in particular, the coherence of conversation with a VH. This experiment was performed in combination with another experiment evaluating two display technologies. As that aspect of the study is not relevant to this poster, it will be mentioned only in the Materials section. Participants who interacted with a low-coherence VH looked around the room markedly more than participants interacting with a high-coherence VH, demonstrating that the level of coherence of VHs can have a detectable effect on user behavior and that head and gaze behavior can be used to evaluate the quality of a VH interaction.

We report on the design and results of an experiment investigating factors influencing Slater's Plausibility Illusion (Psi) in virtual environments (VEs). Slater proposed Psi and Place Illusion (PI) as orthogonal components of virtual experience which contribute to realistic response in a VE. PI corresponds to the traditional conception of presence as "being there," so there exists a substantial body of previous research relating to PI, but very little relating to Psi. We developed this experiment to investigate the components of plausibility illusion using subjective matching techniques similar to those used in color science. Twenty-one participants each experienced a scenario with the highest level of coherence (the extent to which a scenario matches user expectations and is internally consistent), then in eight different trials chose transitions from lower-coherence to higher-coherence scenarios with the goal of matching the level of Psi they felt in the highest-coherence scenario. At each transition, participants could change one of the following coherence characteristics: the behavior of the other virtual humans in the environment, the behavior of their own body, the physical behavior of objects, or the appearance of the environment. Participants tended to choose improvements to the virtual body before any other improvements. This indicates that having an accurate and well-behaved representation of oneself in the virtual environment is the most important contributing factor to Psi. This study is the first to our knowledge to focus specifically on coherence factors in virtual environments.

We present a new method for evaluating user experience in interactions with virtual humans (VHs). We code the conversational errors made by the VH. These errors, in addition to the duration of the interaction and the numbers of statements made by the participant and the VH, provide objective, quantitative data about the virtual social interaction. We applied this method to a set of previously collected interactions between medical students and VH patients and present preliminary results. The error metrics do not correlate with traditional measures of the quality of a virtual experience, e.g. presence and copresence questionnaires. The error metrics were significantly correlated with scores on the Maastricht Assessment of Simulated Patients (MaSP), a scenario-appropriate measure of simulation quality, suggesting further investigation is warranted.

Projectors equipped with wide-angle lenses can have an advantage over traditional projectors in creating immersive display environments since they can be placed very close to the display surface to reduce user shadowing issues while still producing large images. However, wide-angle projectors exhibit severe image distortion requiring the image generator to correctively pre-distort the output image. In this paper, we describe a new technique based on Raskar's (1998) two-pass rendering algorithm that is able to correct for both arbitrary display surface geometry and the extreme lens distortion caused by fisheye lenses. We further detail how the distortion correction algorithm can be implemented in a real-time shader program running on a commodity GPU to create low-cost, personal surround environments

Using projectors to create perspectively correct imagery on arbitrary display surfaces requires geometric knowledge of the display surface shape, the projector calibration, and the user’s position in a common coordinate system. Prior solutions have most commonly modeled the display surface as a tessellated mesh derived from the 3D-point cloud acquired during system calibration. In this paper we describe a method for functional reconstruction of the display surface, which takes advantage of the knowledge that most interior display spaces (e.g. walls, floors, ceilings, building columns) are piecewise planar. Using a RANSAC algorithm to recursively fit planes to a 3D-point cloud sampling of the surface, followed by a conversion of the plane definitions into simple planar polygon descriptions, we are able to create a geometric model which is less complex than a dense tessellated mesh and offers a simple method for accurately modeling the corners of rooms. Planar models also eliminate subtle, but irritating, texture distortion often seen in tessellated mesh approximations to planar surfaces.