1,721,140 research outputs found
The sense of being there during online classes: analysis of usability and presence in web-conferencing systems and virtual reality social platforms
No full textDue to the Covid-19 pandemic, millions of people had to stay at home for several months and to move their everyday activities online. From smart-working to online learning, also considering entertainment activities, people started to extensively use platforms for remote communication and for sharing video, text, and audio content. Such systems are able to cope with the need of communicating, but the common feeling is that people, and especially students, are missing the physical relationships with classmates and colleagues. In this paper, we analyse two modalities that can be used to give an online University lecture, by focusing on the ‘sense of presence’, i.e. on the ability to produce into students the psychological sense of being in a classroom together with the teacher and their classmates. We consider a standard web-conferencing system, and a Virtual Reality social platform. We also take into account the ‘usability’ factors, to understand if extended reality systems could be, in a near future, a possible alternative to improve distance lectures and meetings
Assessment of optical see-through head mounted display calibration for interactive augmented reality
No full textInteraction in Augmented Reality environments requires the precise alignment of virtual elements added to the real scene. This can be achieved if the egocentric perception of the augmented scene is coherent in both the virtual and the real reference frames. To this aim, a proper calibration of the complete system, composed of the Augmented Reality device, the user and the environment, should be performed. Over the years, several calibration techniques have been proposed, and objectively evaluating their performance has shown to be troublesome. Since only the user can assess the hologram alignment fidelity, most researchers quantify the calibration error with subjective data from user studies. This paper describes the calibration process of an optical see-through device, based on a visual alignment method, and proposes a technique to objectively quantify the residual misalignment error
Detection and Localization of Changes in Immersive Virtual Reality
No full textImmersive visualization, i.e. the presentation of stimuli, data, and information with head-mounted displays and virtual reality (VR) techniques, is nowadays common in several application contexts. For effective use of such setups, it is worth studying if the attentional mechanisms are affected (improved or worsened) in any way, or if human performances in detecting changes are similar to what happens in the real world. Here, we focus on assessing the Visual Working Memory (VWM) in VR by using a change localization task, and on developing a computational model to account for experiment outcomes. In the change localization experiment, we have four factors: set size, spatial layout, visual angle, and observation time. The results show that there is a limit of the VWM capacity around 7 ± 2 items, as reported in the literature. The localization precision is affected by visual angle and observation time (p < 0.0001), only. The proposed model shows high agreement with the human data (r > 0.91 and p < 0.05)
Modelling Foveated Depth-of-field Blur for Improving Depth Perception in Virtual Reality
No full textThis paper presents a technique to incorporate spatial blur effects in virtual reality devices. The considered spatial blur is based on foveation and defocus blur: concepts inspired by the human visual system. The proposed technique can be applied to any head-mounted display as a post-processing step. Our foveated depth-of-field method removes intensity leakage artifacts in the transitory regions and works in real-Time. We verify the usefulness of our technique by conducting a pilot study on depth perception in virtual environments. In the conducted user study, systems integrated with our blur effect provided a better estimation of object depth in the peripheral regions
Visualization and Interaction Technologies in Serious and Exergames for Cognitive Assessment and Training: A Survey on Available Solutions and Their Validation
No full textExergames and serious games, based on standard personal computers, mobile devices and gaming consoles or on novel immersive Virtual and Augmented Reality techniques, have become popular in the last few years and are now applied in various research fields, among which cognitive assessment and training of heterogeneous target populations. Moreover, the adoption of Web based solutions together with the integration of Artificial Intelligence and Machine Learning algorithms could bring countless advantages, both for the patients and the clinical personnel, as allowing the early detection of some pathological conditions, improving the efficacy and adherence to rehabilitation processes, through the personalisation of training sessions, and optimizing the allocation of resources by the healthcare system. The current work proposes a systematic survey of existing solutions in the field of cognitive assessment and training. We evaluate the visualization and interaction technologies commonly adopted and the measures taken to fulfil the need of the pathological target populations. Moreover, we analyze how implemented solutions are validated, i.e. The chosen experimental designs, data collection and analysis. Finally, we consider the availability of the applications and raw data to the large community of researchers and medical professionals and the actual application of proposed solutions in the standard clinical practice. Despite the potential of these technologies, research is still at an early stage. Although the recent release of accessible immersive virtual reality headsets and the increasing interest on vision-based techniques for tracking body and hands movements, many studies still rely on non-immersive virtual reality (67.2%), mainly mobile and personal computers, and standard gaming tools for interactions (41.5%). Finally, we highlight that although the interest of research community in this field is increasingly higher, the sharing of dataset (10.6%) and implemented applications (3.8%) should be promoted and the number of healthcare structures which have successfully introduced the new technological approaches in the treatment of their host patients is limited (10.2%)
Passive Haptic Feedback for More Realistic and Efficient Grasping Movements in Virtual Environments
No full textAchieving natural interaction in virtual environments is essential to create realistic simulations in various fields, including healthcare and education. The ability to interact in Virtual Reality (VR) in a natural way, through a combination of visual and physical feedback can greatly enhance the experience and effectiveness of these simulations. Recent works have shown that the lack of haptic and tactile feedback produces significant differences in grasping actions performed in immersive VR, with respect to the same actions performed in the real world. The passive haptics approach, which relies on physical proxies to introduce tactile feedback in VR, has been explored to address this issue. This work focuses on a specific interaction task that involves both hand movements and grasping: pouring coffee into a cup and mimicking the action of drinking it. We take into account three different scenarios: a traditional VR environment where virtual objects don’t have any real counterparts; an MR environment that uses an ecological object substitution technique where the user can interact with real objects that are tracked in real-time and see a virtual counterpart; and the corresponding real scenario. We compute the Minimum Jerk Cost and the Dynamic Time Warping distance between trajectories as metrics to compare movements in the different modalities in terms of their smoothness and trajectory shape, respectively. Our results show that movements in MR environments are smoother and produce more similar trajectories to real-world movements compared to classical VR environments. This indicates that MR with passive haptic feedback could produce more realistic and efficient human movements in virtual environments
Corporate sustainability assessment through fuzzy topsis
No full textThe aim of this paper is to propose a decisionmaking methodology that enables the analysis and evaluation of sustainability at the corporate level. The proposed methodology grounds on two tools, namely the technique for order preference by similarity to ideal solution (TOPSIS) approach and fuzzy logic. The integration of these tools offers an effective way to deal with two typical issues of sustainability assessment, i.e.: 1) the fact that the company's performance should be frequently evaluated against qualitative key performance indicators; and 2) the fact that to be meaningful, the company's sustainability performance needs to be compared to a reference value, e.g. a threshold or benchmark, to evaluating how the company is distant from a target. The proposed approach has been applied to a real firm, operating in the food machinery industry, for testing purpose. The main pros and cons of the approach are described
A study on the role of feedback and interface modalities for natural interaction in virtual reality environments
No full textThis paper investigates how people interact in immersive virtual reality environments, during selection and manipulation tasks in different conditions. We take into consideration two different task complexities, two interaction modalities (i.e. HTC Vive Controller and Leap Motion) and three feedback provided to the user (i.e. none, audio and visual) with the aim of understanding their influence on performances and preferences. Although adding feedback to the touchless interface may help users to overcome instability problems, providing information about the objects state, i.e. grabbed or released, they do not substantially improve performances. Moreover, both touchful and touchless modalities have been shown to be effective for interaction. The analysis presented in this paper may play a role in the design of natural and ecological interfaces, especially in the case non-invasive devices are needed
A Comparative Study on Locomotion Methods and Distance Perception in Immersive Virtual Reality
No full textAccurately perceiving distances in virtual reality (VR) remains a challenge due to discrepancies between real-world and VR spatial experiences. This study compares four VR locomotion methods - Teleport, Joystick, Arms Swinging, and Real Walking - by evaluating distance perception, spatial orientation, and user experience. In an exploratory within-subject study, participants navigated a virtual environment, estimated distances, and completed various questionnaires (SSQ, IPQ, SUS, NASA TLX, and a comparison questionnaire). Results showed a mismatch between user preference and performance: while Arms Swinging was the least preferred method, it provided the most accurate distance estimation and spatial orientation
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