Virtual Reality最新文献

Extended reality (XR) experiences are on the verge of becoming widely adopted in diverse application domains. An essential part of the technology is accurate tracking and localization of the headset to create an immersive experience. A subset of the applications require perfect co-location between the real and the virtual world, where virtual objects are aligned with real-world counterparts. Current headsets support co-location for small areas, but suffer from drift when scaling up to larger ones such as buildings or factories. This paper proposes tools and solutions for this challenge by splitting up the simultaneous localization and mapping (SLAM) into separate mapping and localization stages. In the pre-processing stage, a feature map is built for the entire tracking area. A global optimizer is applied to correct the deformations caused by drift, guided by a sparse set of ground truth markers in the point cloud of a laser scan. Optionally, further refinement is applied by matching features between the ground truth keyframe images and their rendered-out SLAM estimates of the point cloud. In the second, real-time stage, the rectified feature map is used to perform localization and sensor fusion between the global tracking and the headset. The results show that the approach achieves robust co-location between the virtual and the real 3D environment for large and complex tracking environments.

Speech anxiety, or Glossophobia, currently affects approximately 75% of the population with potentially severe negative effects on those with this condition. There are several treatments currently available with research showing that the use of Virtual Reality (VR) as a non-pharmacologic treatment can have positive effects on individuals suffering from such social phobias. However, there is a significant lack of treatments currently available for speech anxiety, even though such a large number of the population are affected by it. In this paper, we aim to contribute to efforts to improve the effects of speech anxiety through a VR intervention. Our VR solution was designed following the Exposure Therapy approach for treating social anxiety disorders. The evaluation of this work was twofold: A. to assess the ability of our solution to positively change participants’ perception of factors related to non-verbal communication contributing to anxiety toward public speaking, and B. to determine whether it is able to induce a sense of presence. We carried out an empirical evaluation study that measured participants’ self-reported anxiety level towards public speaking using the Personal Report of Public Speaking Anxiety and their perceived sense of presence using the iGroup Presence Questionnaire. Our results demonstrate the potential of VR Exposure Therapy solutions to assist towards positively changing perception of factors related to non-verbal communication skills that contribute to increasing public speaking anxiety for participants suffering from self-reported speech anxiety symptoms. Our findings are of wider importance as they contribute to ongoing efforts to improve social anxiety-related phobias.

In virtual reality, redirected walking (RDW) enables users to stay within the tracking area while feeling that they are traveling in a virtual space that is larger than the physical space. RDW uses a visual attractor to the user’s sight and scene manipulation for intermittent reorientation. However, repeated usage can hinder the virtual world immersion and weaken the reorientation performance. In this study, we propose using sounds and smells as alternative stimuli to draw the user’s attention implicitly and sustain the attractor’s performance for intermittent reorientation. To achieve this, we integrated visual, auditory, and olfactory attractors into an all-in-one stimulation system. Experiments revealed that the auditory attractor caused the fastest reorientation, the olfactory attractor induced the widest angular difference, and the attractor with the combined auditory and olfactory stimuli induced the largest angular speed, keeping users from noticing the manipulation. The findings demonstrate the potential of nonvisual attractors to reorient users in situations requiring intermittent reorientation.

In this work, we explore the potential and limitations of simulating gaze-contingent tunnel vision conditions using Virtual Reality (VR) with built-in eye tracking technology. This approach promises an easy and accessible way of expanding study populations and test groups for visual training, visual aids, or accessibility evaluations. However, it is crucial to assess the validity and reliability of simulating these types of visual impairments and evaluate the extend to which participants with simulated tunnel vision can represent real patients. Two age-matched participant groups were acquired: The first group (n = 8, aged 20–60, average 49.1 ± 13.2) consisted of patients diagnosed with Retinitis pigmentosa (RP). The second group (n = 8, aged 27–59, average 46.5 ± 10.8) consisted of visually healthy participants with simulated tunnel vision. Both groups carried out different visual tasks in a virtual environment for 30 min per day over the course of four weeks. Task performances as well as gaze characteristics were evaluated in both groups over the course of the study. Using the ’two one-sided tests for equivalence’ method, the two groups were found to perform similar in all three visual tasks. Significant differences between groups were found in different aspects of their gaze behavior, though most of these aspects seem to converge over time. Our study evaluates the potential and limitations of using Virtual Reality technology to simulate the effects of tunnel vision within controlled virtual environments. We find that the simulation accurately represents performance of RP patients in the context of group averages, but fails to fully replicate effects on gaze behavior.

Aimed at limitations in the description and expression of three-dimensional (3D) physical information in two-dimentsional (2D) medical images, feature extraction and matching method based on the biomedical characteristics of skeletons is employed in this paper to map the 2D images of skeletons into a 3D digital model. Augmented reality technique is used to realize the interactive presentation of skeleton models. Main contents of this paper include: Firstly, a three-step reconstruction method is used to process the bone CT image data to obtain its three-dimensional surface model, and the corresponding 2D–3D bone library is established based on the identification index of the 2D image and the 3D model; then, a fast and accurate feature extraction and matching algorithm is developed to realize the recognition, extraction, and matching of 2D skeletal features, and determine the corresponding 3D skeleton model according to the matching result. Finally, based on the augmented reality technique, an interactive immersive presentation system is designed to achieve visual effects of the virtual human bone model superimposed and rendered in the world scenes, which improves the effectiveness of information expression and transmission, as well as the user's immersion and embodied experience.

This study explores the effect of the experimenter’s gender/sex and its interaction with the participant’s gender/sex as potential contributors to the replicability crisis, particularly in the man-gendered domain of VR. 75 young men and women from Western France were randomly evaluated by either a man or a woman during a 13-min immersion in a first-person shooter game. Self-administered questionnaires were used to measure variables commonly assessed during VR experiments (sense of presence, cybersickness, video game experience, flow). MANOVAs, ANOVAs and post-hoc comparisons were used. Results indicate that men and women differ in their reports of cybersickness and video game experience when rated by men, whereas they report similar measures when rated by women. These findings are interpreted as consequences of the psychosocial stress triggered by the interaction between the two genders/sexes, as well as the gender conformity effect induced, particularly in women, by the presence of a man in a masculine domain. Corroborating this interpretation, the subjective measure of flow, which is not linked to video games and/or computers, does not seem to be affected by this experimental effect. Methodological precautions are highlighted, notably the brief systematic description of the experimenter, and future exploratory and confirmatory studies are outlined.

Graphical abstract

Mixed reality technologies, such as virtual (VR) and augmented (AR) reality, present promising opportunities to advance education and professional training due to their adaptability to diverse contexts. Distortions in the perceived distance in such mediated conditions, however, are well documented and have imposed nontrivial challenges that complicate and limit transferring task performance in a virtual setting to the unmediated reality (UR). One potential source of the distance distortion is the vergence-accommodation conflict—the discrepancy between the depth specified by the eyes’ accommodative state and the angle at which the eyes converge to fixate on a target. The present study involved the use of a manual pointing task in UR, VR, and AR to quantify the magnitude of the potential depth distortion in each modality. Conceptualizing the effect of vergence-accommodation offset as a constant offset to the vergence angle, a model was developed based on the stereoscopic viewing geometry. Different versions of the model were used to fit and predict the behavioral data for all modalities. Results confirmed the validity of the conceptualization of vergence-accommodation as a device-specific vergence offset, which predicted up to 66% of the variance in the data. The fitted parameters indicate that, due to the vergence-accommodation conflict, participants’ vergence angle was driven outwards by approximately 0.2°, which disrupted the stereoscopic viewing geometry and produced distance distortion in VR and AR. The implications of this finding are discussed in the context of developing virtual environments that minimize the effect of depth distortion.

Balance problems are widely reported in Pediatric Brain Tumor Survivors (PBTS) due to tumor localization and the side effects of medical treatment. This study investigates the effects of conventional versus video-based games exercise training (exergaming) on balance in PBTS. The present study was a randomized controlled trial. The study included 23 PBTS who were randomized to a Video-Based balance exergaming Group (VBG) or Conventional balance exercise training Group (CG). In both groups, the interventions were targeted to the balance function and balance exercise training was administered twice a week for 8 weeks. VBG exercised using selected Nintendo Wii Fit Plus® balance games while CG received a specially designed balance training using conventional physiotherapy methods. The primary outcome was the balance tests (Timed Up and Go and Nintendo® Wii™ Center of Gravity: COG), and the secondary outcomes were the functional tests (10-m walking, 2-min walking, 5-step climb/descent/times), and disease effect test (PedsQL Brain Tumor Module). The outcomes were assessed before and after the intervention. At baseline, no significant clinical and outcome assessment differences existed between both groups except for COG (p = 0.0495). After training, overall scores for balance, functional, disease effect tests significantly improved in VBG (p < 0.05) while progress observed in CG was not significant (p > 0.05). Video-based balance exergaming was found effective and more so than conventional balance exercise training in PBTS. Greater effectiveness of exergaming is thought to be due to increased motivation and effort of the children who are more attracted to gaming than conventional exercising. Exergaming could be beneficial both in clinical and home settings with physiotherapist supervision and may reduce the costs of treatment while improving their health-related quality of life.

This study aims to identify effective ways to design virtual rehabilitation to obtain physical improvement (e.g. balance and gait) and support engagement (i.e. motivation) for people with osteoporosis or other musculoskeletal disorders. Osteoporosis is a systemic skeletal disorder and is among the most prevalent diseases globally, affecting 0.5 billion adults. Despite the fact that the number of people with osteoporosis is similar to, or greater than those diagnosed with cardiovascular disease and dementia, osteoporosis does not receive the same recognition. Worldwide, osteoporosis causes 8.9 million fractures annually; it is associated with substantial pain, suffering, disability and increased mortality. The importance of physical therapy as a rehabilitation strategy to avoid osteoporosis fracture cannot be over-emphasised. However, the main rehabilitation challenges relate to engagement and participation. The use of virtual rehabilitation to address such challenges in the delivery of physical improvement is gaining in popularity. As there currently is a paucity of literature applying virtual rehabilitation to patients with osteoporosis, the authors broadened the search parameters to include articles relating to the virtual rehabilitation of other skeletal disorders (e.g. Ankylosing spondylitis, spinal cord injury, motor rehabilitation, etc.). This systematic review initially identified 130 titles, from which 23 articles (involving 539 participants) met all eligibility and selection criteria. Four groups of devices supporting virtual rehabilitation were identified: a head-mounted display, a balance board, a camera and more specific devices. Each device supported physical improvement (i.e. balance, muscle strength and gait) post-training. This review has shown that: (a) each device allowed improvement with different degrees of immersion, (b) the technology choice is dependent on the care need and (c) virtual rehabilitation can be equivalent to and enhance conventional therapy and potentially increase the patient’s engagement with physical therapy.

In recent decades, the senior adults population worldwide has increased, as well as the medical conditions related to aging, such as cognitive decline. Virtual reality (VR) games are a valuable addition to conventional cognitive rehabilitation as they increase engagement to the therapy through customization, socialization, immersion, and feedback. This review, performed according to PRISMA protocol, addresses the following questions: How VR games have been used for cognitive rehabilitation?, What cognitive domains have been addressed by VR games and in which populations have these games been used?, Which features have been considered to improve engagement in VR games for cognitive rehabilitation?, How is the difficulty adjustment of exercises carried out in VR games for cognitive rehabilitation?. We found 25 scientific works related to these questions, 92% of them treating one cognitive domain at a time, despite the fact that the related literature recognizes the value of training multiple domains simultaneously. Our review indicates that, despite the existence of serious VR games for working memory training, such as those described in Flak et al. (Front Psychol 10:807, 2019. https://doi.org/10.3389/fpsyg.2019.00807), to our knowledge, there are no applications that simultaneously address multiple cognitive domains and incorporate dynamic difficulty adjustment, which are important to ensure ecological validity of therapy and therapy adherence, respectively. In addition, we found that games themselves could be used to monitor the user’s progression. It is also important to determine the impact of multiplayer interactions in the game, test difficulty adjustment approaches that use physiological variables, and define difficulty-skill relationships aligned with the user’s preferences. This paper concludes that the main barriers to implement dynamic difficulty adjustment in VR games for cognitive rehabilitation are: (i) the absence of metrics to estimate when the game offers to the players a challenge adapted their skills, and (ii) the lack of a conceptual framework that integrates relevant theories such as state of flow, cognitive load, cognitive rehabilitation, and feedback systems.