4,651 research outputs found

    The Big Picture on Small Screens Delivering Acceptable Video Quality in Mobile TV

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    Mobile TV viewers can change the viewing distance and (on some devices) scale the picture to their preferred viewing ratio, trading off size for angular resolution. We investigated optimal trade-offs between size and resolution through a series of studies. Participants selected their preferred size and rated the acceptability of the visual experience on a 200ppi device at a 4: 3 aspect ratio. They preferred viewing ratios similar to living room TV setups regardless of the much lower resolution: at a minimum 14 pixels per degree. While traveling on trains people required videos with a height larger than 35mm

    Space games: evaluating game-based virtual reality in higher education

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    With increasing global dependence on satellite technology, space traffic has grown exponentially over the last decade. Enhanced education and training of future mission operators will be necessary to meet this growing demand. The complexity of satellite mission operations poses a challenge in education and training. Remote spacecraft are elusive and difficult for a trainee to visualize and involve a steep learning curve. However, the integration of game-based virtual reality into spacecraft simulation and training may assist in overcoming these challenges. This research study explored the integration of game-based virtual reality into a university course involving spacecraft operations. Virtual spacewalks allowed student participants to conduct visual inspections and interact directly with spacecraft components. The immersive virtual reality environment prolonged cognitive engagement and game mechanics influenced motivation, both cornerstones in learning. After completing the training scenarios, user experience was assessed with several validated scales measuring system usability, user satisfaction, cognitive loading, and any potential simulator sickness. Results revealed satisfactory scores in all categories with minimal simulator sickness. The integrated use of game-based virtual reality in the classroom provided an enhanced learning experience in a safe and repeatable environment that might be difficult with traditional teaching methods. This paper will evaluate game-based virtual reality when integrated into higher education or other training environment

    Camera Stabilization in 360° Videos and Its Impact on Cyber Sickness, Environmental Perceptions, and Psychophysiological Responses to a Simulated Nature Walk: A Single-Blinded Randomized Trial

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    Immersive virtual environments (IVEs) technology has emerged as a valuable tool to environmental psychology research in general, and specifically to studies of human–nature interactions. However, virtual reality is known to induce cyber sickness, which limits its application and highlights the need for scientific strategies to optimize virtual experiences. In this study, we assessed the impact of improved camera stability on cyber sickness, presence, and psychophysiological responses to a simulated nature walk. In a single-blinded trial, 50 participants were assigned to watch, using a head-mounted display, one of two 10-min 360° videos showing a first-person nature walk: one video contained small-magnitude scene oscillations associated with cameraman locomotion, while in the other video, the oscillations were drastically reduced thanks to an electric stabilizer and a dolly. Measurements of cyber sickness (in terms of both occurrence and severity of symptoms), perceptions of the IVE (presence and perceived environmental restorativeness), and indicators of psychophysiological responses [affect, enjoyment, and heart rate (HR)] were collected before and/or after the exposure. Compared to the low-stability (LS) condition, in the high-stability (HS) condition, participants reported lower severity of cyber sickness symptoms. The delta values for pre–post changes in affect for the LS video revealed a deterioration of participants’ affect profile with a significant increase in ratings of negative affect and fatigue, and decrease in ratings of positive affect. In contrast, there were no pre–post changes in affect for the HS video. No differences were found between the HS and LS conditions with respect to presence, perceived environmental restorativeness, enjoyment, and HR. Cyber sickness was significantly correlated with all components of affect and enjoyment, but not with presence, perceived environmental restorativeness, or HR. These findings demonstrate that improved camera stability in 360° videos is crucial to reduce cyber sickness symptoms and negative affective responses in IVE users. The lack of associations between improved stability and presence, perceived environmental restorativeness, and HR suggests that other aspects of IVE technology must be taken into account in order to improve virtual experiences of nature.publishedVersio

    The quality of experience of emerging display technologies

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    As new display technologies emerge and become part of everyday life, the understanding of the visual experience they provide becomes more relevant. The cognition of perception is the most vital component of visual experience; however, it is not the only cognition that contributes to the complex overall experience of the end-user. Expectations can create significant cognitive bias that may even override what the user genuinely perceives. Even if a visualization technology is somewhat novel, expectations can be fuelled by prior experiences gained from using similar displays and, more importantly, even a single word or an acronym may induce serious preconceptions, especially if such word suggests excellence in quality. In this interdisciplinary Ph.D. thesis, the effect of minimal, one-word labels on the Quality of Experience (QoE) is investigated in a series of subjective tests. In the studies carried out on an ultra-high-definition (UHD) display, UHD video contents were directly compared to their HD counterparts, with and without labels explicitly informing the test participants about the resolution of each stimulus. The experiments on High Dynamic Range (HDR) visualization addressed the effect of the word “premium” on the quality aspects of HDR video, and also how this may affect the perceived duration of stalling events. In order to support the findings, additional tests were carried out comparing the stalling detection thresholds of HDR video with conventional Low Dynamic Range (LDR) video. The third emerging technology addressed by this thesis is light field visualization. Due to its novel nature and the lack of comprehensive, exhaustive research on the QoE of light field displays and content parameters at the time of this thesis, instead of investigating the labeling effect, four phases of subjective studies were performed on light field QoE. The first phases started with fundamental research, and the experiments progressed towards the concept and evaluation of the dynamic adaptive streaming of light field video, introduced in the final phase

    Evaluating 360° media experiences

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    360° media experiences have existed for centuries. Viewing painted panoramas, such as those displayed in the 18th-century rotunda in Leicester Square, was a popular Georgian pastime. Recent advances in capture, processing and display technology have created a surge of interest in the medium, with millions of people now viewing captured 360° media immersively. Despite the popularity of 360° media experiences, there are still substantial technical issues associated with production and distribution, and little research has been done that explores the end-user experience. As these experiences become commonplace, understanding the impact of such media becomes critical. In this work, two user studies were conducted that investigated the effects of 360° media of different forms. The first study looked at the impact of the display type when viewing cinematic virtual reality captured as 360° video. The study used three display types: a head-mounted display (HMD); a standard 16:9 TV; and a focus-plus-context display. Several metrics were explored, including spatial awareness, memory and narrative engagement. The second study investigated the impact of different transition types when exploring static scenes captured as multi-view 360° images in a HMD. The three transitions investigated were a linear movement through a 3D model of the scene, an instantaneous teleportation, and an image-based warp using Möbius transformations. Metrics investigated included spatial awareness, preference, and several subjective qualities such as the feeling of moving through the space. Additionally, an enabling technology for such experiences was investigated. Object removal in 360° images was explored in detail, with extensions for video described for simple cases. Taken together, these three projects further our current understanding of how 360° media can be implemented, and examine some of the most critical aspects of how users engage with these experiences

    On our feet: feasibility trial of an intervention to reduce sedentary behavior and increase physical activity

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    Sedentary behavior (SB) is emerging as an independent risk factor for cardiovascular disease and type 2 diabetes (Katzmarzyk, 2010, Owen et al., 2010), and is a target for intervention. This study examined effects of a Social Cognitive intervention to increase self-efficacy (SE) for reducing SB and increasing PA. Female members (Mage=58.5, SD=12.5 yrs) from seven weight loss support clubs were enrolled in a 6-week intervention (n=40) or waitlisted (n=24) based on club randomization. The intervention, delivered via group sessions and email, used mastery feedback from goal-setting activities along with behavioral cues and modeling to reduce SB and increase steps. Quantitative and qualitative process evaluation data were collected throughout. PA and SB were measured by accelerometers. SE (to reduce SB, to increase light & moderate PA) were measured pre, mid, and post. Repeated-measures MANOVA found no significant change over time or Group x Time interaction for behavior. A significant effect for time was noted for SE to reduce SB (F=3.34, p<.05) and the Group x Time interaction approached significance. SE decreased at mid-point, but increased for the intervention group while the waitlist group continued to fall. Differences between rural and urban women in SB (F=4.69, p<0.04) and SE to reduce SB (F=4.75, p<0.05), were significant, with rural participants having less SB and lower SE to reduce SB than urban peers. Participants' perceptions were examined to provide a contextualized understanding of SB and methods to change behavior. Analysis identified compliance barriers, including required sitting, accuracy of self-monitoring, work and family responsibilities and questions of relevance. Significant differences in SE to reduce SB were seen when compliant participants were compared to non-compliant participants (F=2.44, p<0.05). Behavioral cues and modeled behaviors were less impactful than anticipated. Participants were receptive to monitoring PA via pedometer, though challenges in self-monitoring SB were noted. The role of SE in changing SB needs further study. Findings suggest that interventions must consider contextual factors, such as location and occupation as well as individual factors (SE) and barriers. Future studies should consider the effect of modifying the built-environment on SE to reduce SB and improve methods for self-monitoring

    Classification of soundscapes of urban public open spaces

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    It is increasingly acknowledged by landscape architects and urban planners that the soundscape contributes significantly to the perception of urban public open spaces. Describing and classifying this impact, however, remains a challenge. This article presents a hierarchical method for classification that distinguishes between backgrounded and foregrounded, disruptive and supportive, and finally calming and stimulating soundscapes. This four-class classification is applied to a growing collection of immersive audio-visual recordings of sound environments from around the world that could be explored using virtual reality playback. To validate the proposed methodology, an experiment involving 40 participants and 50 soundscape stimuli collected in urban public open spaces worldwide was conducted. The experiment showed that (1) the virtual reality headset reproduction based on affordable spatial audio with 360-degree video recordings was perceived as ecologically valid in terms of realism and immersion; (2) the proposed classification method results in well-separated classes; (3) membership to these classes could be explained by physical parameters, both regarding sound and vision. Moreover, models based on a limited number of acoustical indicators were constructed that could correctly classify a soundscape in each of the four proposed categories, with an accuracy exceeding 88% on an independent dataset

    Mitigation Of Motion Sickness Symptoms In 360 Degree Indirect Vision Systems

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    The present research attempted to use display design as a means to mitigate the occurrence and severity of symptoms of motion sickness and increase performance due to reduced “general effects” in an uncoupled motion environment. Specifically, several visual display manipulations of a 360° indirect vision system were implemented during a target detection task while participants were concurrently immersed in a motion simulator that mimicked off-road terrain which was completely separate from the target detection route. Results of a multiple regression analysis determined that the Dual Banners display incorporating an artificial horizon (i.e., AH Dual Banners) and perceived attentional control significantly contributed to the outcome of total severity of motion sickness, as measured by the Simulator Sickness Questionnaire (SSQ). Altogether, 33.6% (adjusted) of the variability in Total Severity was predicted by the variables used in the model. Objective measures were assessed prior to, during and after uncoupled motion. These tests involved performance while immersed in the environment (i.e., target detection and situation awareness), as well as postural stability and cognitive and visual assessment tests (i.e., Grammatical Reasoning and Manikin) both before and after immersion. Response time to Grammatical Reasoning actually decreased after uncoupled motion. However, this was the only significant difference of all the performance measures. Assessment of subjective workload (as measured by NASA-TLX) determined that participants in Dual Banners display conditions had a significantly lower level of perceived physical demand than those with Completely Separated display designs. Further, perceived iv temporal demand was lower for participants exposed to conditions incorporating an artificial horizon. Subjective sickness (SSQ Total Severity, Nausea, Oculomotor and Disorientation) was evaluated using non-parametric tests and confirmed that the AH Dual Banners display had significantly lower Total Severity scores than the Completely Separated display with no artificial horizon (i.e., NoAH Completely Separated). Oculomotor scores were also significantly different for these two conditions, with lower scores associated with AH Dual Banners. The NoAH Completely Separated condition also had marginally higher oculomotor scores when compared to the Completely Separated display incorporating the artificial horizon (AH Completely Separated). There were no significant differences of sickness symptoms or severity (measured by self-assessment, postural stability, and cognitive and visual tests) between display designs 30- and 60-minutes post-exposure. Further, 30- and 60- minute post measures were not significantly different from baseline scores, suggesting that aftereffects were not present up to 60 minutes post-exposure. It was concluded that incorporating an artificial horizon onto the Dual Banners display will be beneficial in mitigating symptoms of motion sickness in manned ground vehicles using 360° indirect vision systems. Screening for perceived attentional control will also be advantageous in situations where selection is possible. However, caution must be made in generalizing these results to missions under terrain or vehicle speed different than what is used for this study, as well as those that include a longer immersion time
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