Virtual Reality最新文献

The diffusion of virtual reality urges to solve the problem of vergence-accommodation conflict arising when viewing stereoscopic displays, which causes visual stress. We addressed this issue with an approach based on reducing ocular convergence effort. In virtual environments, vergence can be controlled by manipulating the binocular separation of the virtual cameras. Using this technique, we implemented two quasi-3D conditions characterized by binocular image separations intermediate between 3D (stereoscopic) and 2D (monoscopic). In a first experiment, focused on perceptual aspects, ten participants performed a visuo-manual pursuit task while wearing a head-mounted display (HMD) in head-constrained (non-immersive) condition for an overall exposure time of ~ 7 min. Passing from 3D to quasi-3D and 2D conditions, progressively resulted in a decrease of vergence eye movements—both mean convergence angle (static vergence) and vergence excursion (dynamic vergence)—and an increase of hand pursuit spatial error, with the target perceived further from the observer and larger. Decreased static and dynamic vergence predicted decreases in asthenopia trial-wise. In a second experiment, focused on tolerance aspects, fourteen participants performed a detection task in near-vision while wearing an HMD in head-free (immersive) condition for an overall exposure time of ~ 20 min. Passing from 3D to quasi-3D and 2D conditions, there was a general decrease of both subjective and objective visual stress indicators (ocular convergence discomfort ratings, cyber-sickness symptoms and skin conductance level). Decreased static and dynamic vergence predicted the decrease in these indicators. Remarkably, skin conductance level predicted all subjective symptoms, both trial-wise and session-wise, suggesting that it could become an objective replacement of visual stress self-reports. We conclude that relieving convergence effort by reducing binocular image separation in virtual environments can be a simple and effective way to decrease visual stress caused by stereoscopic HMDs. The negative side-effect—worsening of spatial vision—arguably would become unnoticed or compensated over time. This initial proof-of-concept study should be extended by future large-scale studies testing additional environments, tasks, displays, users, and exposure times.

The application of virtual reality to the study of conversation and social interaction is a relatively new field of study. While the affordances of VR in the domain compared to traditional methods are promising, the current state of the field is plagued by a lack of methodological standards and shared understanding of how design features of the immersive experience impact participants. In order to address this, this paper develops a relationship map between design features and experiential outcomes, along with expectations for how those features interact with each other. Based on the results of a narrative review drawing from diverse fields, this relationship map focuses on dyadic conversations with agents. The experiential outcomes chosen include presence & engagement, psychological discomfort, and simulator sickness. The relevant design features contained in the framework include scenario agency, visual fidelity, agent automation, environmental context, and audio features. We conclude by discussing the findings of the review and framework, such as the multimodal nature of social VR being highlighted, and the importance of environmental context, and lastly provide recommendations for future research in social VR.

Collision feedback about instrument and environment interaction is often lacking in robotic surgery training devices. The PoLaRS virtual reality simulator is a newly developed desk trainer that overcomes drawbacks of existing robot trainers for advanced laparoscopy. This study aimed to assess the effect of haptic and visual feedback during training on the performance of a robotic surgical task. Robotic surgery-naïve participants were randomized and equally divided into two training groups: Haptic and Visual Feedback (HVF) and No Haptic and Visual Feedback. Participants performed two basic virtual reality training tasks on the PoLaRS system as a pre- and post-test. The measurement parameters Time, Tip-to-tip distance, Path length Left/Right and Collisions Left/Right were used to analyze the learning curves and statistically compare the pre- and post-tests performances. In total, 198 trials performed by 22 participants were included. The visual and haptic feedback did not negatively influence the time to complete the tasks. Although no improvement in skill was observed between pre- and post-tests, the mean rank of the number of collisions of the right grasper (dominant hand) was significantly lower in the HVF feedback group during the second post-test (Mean Rank = 8.73 versus Mean Rank = 14.27, U = 30.00, p = 0.045). Haptic and visual feedback during the training on the PoLaRS system resulted in fewer instrument collisions. These results warrant the introduction of haptic feedback in subjects with no experience in robotic surgery. The PoLaRS system can be utilized to remotely optimize instrument handling before commencing robotic surgery in the operating room.

Perturbations in virtual reality (VR) lead to sensorimotor adaptation during exposure, but also to aftereffects once the perturbation is no longer present. An experiment was conducted to investigate the impact of different task instructions and body representation on the magnitude and the persistence of these aftereffects. Participants completed the paradigm of sensorimotor adaptation in VR. They were assigned to one of three groups: control group, misinformation group or arrow group. The misinformation group and the arrow group were each compared to the control group to examine the effects of instruction and body representation. The misinformation group was given the incorrect instruction that in addition to the perturbation, a random error component was also built into the movement. The arrow group was presented a virtual arrow instead of a virtual hand. It was hypothesised that both would lead to a lower magnitude and persistence of the aftereffect because the object identity between hand and virtual representation would be reduced, and errors would be more strongly attributed to external causes. Misinformation led to lower persistence, while the arrow group showed no significant differences compared to the control group. The results suggest that information about the accuracy of the VR system can influence the aftereffects, which should be considered when developing VR instructions. No effects of body representation were found. One possible explanation is that the manipulated difference between abstract and realistic body representation was too small in terms of object identity.

Real-time performance is critical for Augmented Reality (AR) systems as it directly affects responsiveness and enables the timely rendering of virtual content superimposed on real scenes. In this context, we present the DARLENE wearable AR system, analysing its specifications, overall architecture and core algorithmic components. DARLENE comprises AR glasses and a wearable computing node responsible for several time-critical computation tasks. These include computer vision modules developed for the real-time analysis of dynamic scenes supporting functionalities for instance segmentation, tracking and pose estimation. To meet real-time requirements in limited resources, concrete algorithmic adaptations and design choices are introduced. The proposed system further supports real-time video streaming and interconnection with external IoT nodes. To improve user experience, a novel approach is proposed for the adaptive rendering of AR content by considering the user’s stress level, the context of use and the environmental conditions for adjusting the level of presented information towards enhancing their situational awareness. Through extensive experiments, we evaluate the performance of individual components and end-to-end pipelines. As the proposed system targets time-critical security applications where it can be used to enhance police officers’ situational awareness, further experimental results involving end users are reported with respect to overall user experience, workload and evaluation of situational awareness.

Recent literature has revealed that when users reach to select objects in VR, they can adapt how they move (i.e., the kinematic properties of their reaches) depending on the: (1) direction they move, (2) hand they use, and (3) side of the body where the movement occurs. In the present work, we took a more detailed look at how kinematic properties of reaching movements performed in VR change as a function of movement direction for reaches performed on each side of the body using each hand. We focused on reaches in 12 different directions that either involved moving inward (toward the body midline) or outward (away from the body midline). Twenty users reached in each direction on both left and right sides of their body, using both their dominant and non-dominant hands. The results provided a fine-grained account of how kinematic properties of virtual hand reaches change as a function of movement direction when users reach on either side of their body using either hand. The findings provide practitioners insights on how to interpret the kinematic properties of reaching behaviors in VR, which has applicability in emerging contexts that include detecting VR usability issues and using VR for stroke rehabilitation.

Augmented reality applications can be used in an educational context to facilitate learning. In particular, augmented reality has been successfully used as a tool to boost students’ engagement and to improve their understanding of complex topics. Despite this, augmented reality usage is still not common in schools and it still offers mostly individual experiences, lacking collaboration capabilities which are of paramount importance in a learning environment. This work presents an application called ARoundTheWorld, a multiplatform augmented reality application for education. It is based on a software architecture, designed with the help of secondary school teachers, that provides interoperability, multi-user support, integration with learning management systems and data analytics capabilities, thus simplifying the development of collaborative augmented reality learning experiences. The application has been tested by 44 students and 3 teachers from 3 different educational institutions to evaluate the usability as well as the impact of collaboration functionalities in the students’ engagement. Qualitative and quantitative results show that the application fulfils all the design objectives identified by teachers as key elements for augmented reality educational applications. Furthermore, the application was positively evaluated by the students and it succeeded in promoting collaborative behaviour. These results show that ARoundTheWorld, and other applications built using the same architecture, could be easily developed and successfully integrated into existing schools curricula.

In this paper, we present a virtual reality interactive tool for generating and manipulating visualizations for high-dimensional data in a natural and intuitive stereoscopic way. Our tool offers support for a diverse range of dimensionality reduction (DR) algorithms, enabling the transformation of complex data into insightful 2D or 3D representations within an immersive VR environment. The tool also allows users to include annotations with a virtual pen using hand tracking, to assign class labels to the data observations, and to perform simultaneous visualization with other users within the 3D environment to facilitate collaboration.

Abstract

Human–robot interaction (HRI), which studies the interaction between robots and humans, appears as a promising research idea for the future of smart factories. In this study, HoloLens as ground control station (HoloGCS) is implemented, and its performance is discussed. HoloGCS is a mixed reality-based system for controlling and monitoring unmanned aerial vehicles (UAV). The system incorporates HRI through speech commands and video streaming, enabling UAV teleoperation. HoloGCS provides a user interface that allows operators to monitor and control the UAV easily. To demonstrate the feasibility of the proposed systems, a user case study (user testing and SUS-based questionnaire) was performed to gather qualitative results. In addition, throughput, RTT, latency, and speech accuracy were also gathered and analyzed to evaluate quantitative results.

Total hip arthroplasty (or total hip replacement) is the current surgical solution for the treatment of advanced coxarthrosis, with the objective of providing mobility and pain relief to patients. For this purpose, surgery can be planned using preoperative images acquired from the patient and navigation systems can also be used during the intervention. Robots have also been used to assist in interventions. In this work, we propose a new mixed reality application for total hip arthroplasty. The surgeon only has to wear HoloLens 2. The application does not require acquiring preoperative or intraoperative images of the patient and uses hand interaction. Interaction is natural and intuitive. The application helps the surgeon place a virtual acetabular cup onto the patient's acetabulum as well as define its diameter. Similarly, a guide for drilling and implant placement is defined, establishing the abduction and anteversion angles. The surgeon has a direct view of the operating field at all times. For validation, the values of the abduction and anteversion angles offered by the application in 20 acetabular cup placements have been compared with real values (ground-truth). From the results, the mean (standard deviation) is 0.375 (0.483) degrees for the error in the anteversion angle and 0.1 (0.308) degrees for the abduction angle, with maximum discrepancies of 1 degree. A study was also carried out on a cadaver, in which a surgeon verified that the application is suitable to be transferred to routine clinical practice, helping in the guidance process for the implantation of a total hip prosthesis.