Immersive media such as virtual reality, augmented reality, and 360° video have seen tremendous technological developments in recent years. Furthermore, the advances in head-mounted displays (HMDs) offer the users increased immersive experiences compared to conventional displays. To develop novel immersive media systems and services that satisfy the expectations of the users, it is essential to conduct subjective tests revealing users’ perceived quality of immersive media. However, due to the new viewing dimensions provided by HMDs and the potential of interacting with the content, a wide range of subjective tests are required to understand the many aspects of user behavior in and quality perception of immersive media. The ground truth obtained by such subjective tests enable the development of optimized immersive media systems that fulfill the expectations of the users. This article focuses on the consistency of 360° video quality assessment to reveal whether users’ subjective quality assessment of such immersive visual stimuli changes fundamentally over time or is kept consistent for each user. A pilot study was conducted under pandemic conditions with participants given the task of rating the quality of 360° video stimuli on an HMD in standing and seated viewing. The choice of conducting a pilot study is motivated by the fact that immersive media impose high cognitive load on the participants and the need to keep the number of participants under pandemic conditions as low as possible. To gain insight into the consistency of the participants’ 360° video assessment over time, three sessions were held for each participant and each viewing condition with long and short breaks between sessions. In particular, the opinion scores and head movements were recorded for each participant and each session in standing and seated viewing. The statistical analysis of this data leads to the conjecture that the quality rating stays consistent throughout these sessions with each participant having their own quality assessment signature. The head movements, indicating the participants’ scene exploration during the quality assessment task, also remain consistent for each participant according their individual narrower or wider scene exploration signature. These findings are more pronounced for standing viewing than for seated viewing. This work supports the role of pilot studies being a useful approach of conducting pre-tests on immersive media quality under opportunity-limited conditions and for the planning of subsequent full subjective tests with a large panel of participants. The annotated RQA360 dataset containing the data recorded in the repeated subjective tests is made publicly available to the research community. © 2024. M. Elwardy et al., licensed to EAI. This is an open access article distributed under the terms of the CC BY-NC-SA 4.0, which permits copying, redistributing, remixing, transformation, and building upon the material in any medium so long as the original work is properly cited. doi:10.4108/eetinis.v11i1.4323. All Rights Reserved.

In this paper, a mobile virtual reality (VR) video streaming system is considered and assessed. The system comprises of a VR server, a VR center offering mobile edge computing along with a buffer, and a mobile head-mounted display (HMD). Markov-modulated processes are used to model the arrival and departure traffic at the VR center and the time-varying link quality of the wireless channel to the mobile HMD. As the Markovian arrival process at the VR center is independent of the link quality variations of the wireless channel, the VR center controls the delivery of VR video packets to the mobile HMD subject to the link quality of the wireless channel. The Markov models are used to derive expressions of queueing theoretical performance measures, i.e., throughput, queueing delay, and packet loss probability. Numerical results are provided to investigate performance trade-offs for real data traces. © 2024 IEEE.

The recent advances in immersive technologies have been essential in the development of a wide range of novel standalone and networked immersive media applications. The concepts of virtual reality, augmented reality, and mixed reality relate to different compositions of real and computer-generated virtual objects. In this context, 360° video streaming has become increasingly popular offering improved immersive experiences when viewed on a head-mounted display (HMD). An important component in the development of novel immersive media systems are subjective tests in which participants assess the quality of experience of representative test stimuli. In this paper, the annotated ACR360 dataset is presented which is publicly available on GitHub. The ACR360 dataset contains a wide range of psychophysical and psychophysiological data that was collected in Subjective tests on 360° video quality. The test stimuli were shown on an HMD and rated according to the absolute category rating (ACR) and modified ACR (MACR) methods. To support an easy exploration and utilization of the ACR360 dataset by the research community, its structure on GitHub is described and a comprehensive illustration of analysis options are provided for each data category. The ACR360 dataset may be used for conducting meta-analysis in combination with other datasets to improve precision and to pursue research questions that cannot be answered by an individual study. © 2023 IEEE.

All virtual reality (VR) systems have some inherent hand-controller latency even when operated locally. In remotely rendered VR, additional latency may be added due to the remote transmission of data, commonly conducted through shared low-capacity channels. Increased latency will negatively affect the performance of the human VR operator, but the level of detriment depends on the given task. This work quantifies the relations between aiming accuracy and hand-controller latency, virtual target speed, and the predictability of the target motion. The tested context involves a target that changes direction multiple times while moving in straight lines. The main conclusions are, given the tested context, first, that the predictability of target motion becomes significantly more important as latency and target speed increase. A significant difference in accuracy is generally observed at latencies beyond approximately 130 ms and at target speeds beyond approximately 3.5 degrees/s. Second, latency starts to significantly impact accuracy at roughly 90 ms and approximately 3.5 degrees/s if the target motion cannot be predicted. If it can, the numbers are approximately 130 ms and 12.7 degrees/s. Finally, reaction times are on average 190-200 ms when the target motion changes to a new and unpredictable direction.

The performance of remotely rendered Virtual Reality (VR) is sensitive to temporal disturbances in communication channels. An earlier Quality of Experience (QoE) study of temporal impacts in the form of frame stalls has revealed difficulties with subjective disturbance ratings while performing a task in an interactive 6-degrees-of-freedom (DOF) VR environment. This study follows up on above observation by comparing QoE ratings in the presence and absence of a task. The exploratory findings show that the task-free subjective tests yield lower ratings compared to the subjective tests with task. This indicates that the participants became more sensitive to temporal impairments in the absence of a task. Also, the positive impact of reprojection on the QoE ratings decreased in the task-free environment. The simulator sickness results for individual symptoms were on similar low levels in both settings. The total score (TS) of sickness severity was higher after than before the subjective tests with task while the difference between the TS before and after the task-free subjective tests was insignificant, © 2023 IEEE.

Thanks to its effectiveness, electrodermal activity (EDA) has been previously included as an evaluation metric, within analyses of user experience. In this study, the phasic component of participants’ EDA data is examined in relation to their reported experiences when playing a set of virtual reality games, that featured the HTC Vive and Leap Motion controllers for input. Two models are used in the analysis of the phasic component: a deconvolution model and a convex optimization model. Despite having significant differences in their player experiences, results indicate that there are not many significant differences in the phasic component data. Even if some weak correlations were found, the majority of results show no linear correlations between the phasic component data and the reported experience variables. This shows that the phasic component of EDA data should be further investigated in conjunction with other psychophysiological signals because it has only recently demonstrated a weak link with player experience. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Augmented Reality (AR) and 3D printing have increasingly been used in archaeological and cultural heritage to make artifacts and environments accessible to the general public. This paper presents the case study of the Ljungaviken dog, an archaeological find of dog skeleton remains dated around 8000 years ago. The dog remains have been digitized using 3D scanning and displayed in an AR application. A physical replica has also been created with 3D printing. Both the AR application and the 3D printed copy have been shown in a temporary museum exhibition. In this paper, we present the visitors’ experience evaluation based on a study with 42 participants. Aspects being evaluated are related to the realism, enjoyment, and easiness of use of the AR application. Moreover, the two media are compared in terms of understanding, visual quality, and experience satisfaction. The results show an overall positive experience for both the display solutions, with slightly higher scores for the AR application in the comparison. When asked about overall preference, the participants reported similar results between both media. Due to issues of displaying fragile objects in a museum setting, as well as recent restrictions following pandemic closures and availability, the results presented in this paper show a positive alternative towards using digital artifacts to showcase our cultural heritage. © 2022, Springer Nature Switzerland AG.

Electrodermal activity (EDA) is considered to be an effective metric for measuring changes in the arousal level of people. In this paper, the phasic component of EDA data from players is analyzed in relation to their reported experience from a standardized questionnaire, when interacting with a couple of virtual reality games that featured two different input devices: the HTC Vive and Leap Motion controllers. Initial results show that there are no significant differences in the phasic component data, despite having significant differences in their respective player experience. Furthermore, no linear correlations are found between the phasic component data and the evaluated experience variables, with the only exception of negative affect which features a weak positive correlation. In conclusion, the phasic component of EDA data has here shown a limited correlation with player experience and should be further explored in combination with other psychophysiological signals.

In recent decades, a growing number of museums have adopted digital media, both as an enhancement of exhibitions of real artifacts and as an alternative to traditional display methods. The digital acquisition of artifacts generates accurate 3D replicas that can be displayed via different digital media. With an increase in immersive technologies in the cultural heritage (CH) domain, it is common to see digital artifacts presented in Virtual Reality (VR) and Augmented Reality (AR). This paper presents two user studies conducted in different locations evaluating the use of an AR application in the portrayal of the Mjallby Crucifix artifact. This paper presents the overall results from both user studies evaluating and discussing the AR application on a number of different aspects on a 7-point Likert scale: (1) understanding the artifact, (2) ease of use, (3) object feeling part of reality, (4) perceived visual quality of the object, (5) overall satisfaction experience, and (6) willingness to download the AR application. The results have been compared between genders, age groups, and previous experience with AR. Potential benefits and disadvantages of AR experiences in the context of a museum exhibition were also gathered in free text from the visitors.

Subjective 360° video quality experiments provide the ground truth for developing related systems such that acceptable quality of experience is offered to the users. To obtain statistically meaningful insights from the data recorded in quality experiments, engaging a sufficiently large number of subjects is essential. In contrast to conventional videos, little has been reported on statistical measures that may guide the choice of the number of subjects required for 360° video quality experiments. In this paper, the standard deviation of opinion score (SOS) hypothesis, measuring the diversity among the opinion scores given by a panel of subjects, is used to reveal the number of subjects needed. It is shown that the number of subjects needed varies depending on a threshold on SOS characteristics in terms of diversity among opinion scores. © 2022 IEEE.