Evaluating 360° media experiences

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

Object removal in panoramic media

Due in large part to new consumer virtual reality systems, panoramic media is an increasingly popular image and video format. While the capture of panoramic media is well understood, editing still poses many challenges. In this paper we explore object removal in 360 images. First, a method is proposed in which field-of-view expansion using retargeting techniques is combined with Graphcut Textures to remove objects near the equator of the viewing sphere. Several extensions and refinements are proposed to improve this technique, including how it can be extended to removing objects anywhere on the viewing sphere. Secondly, inpainting in 360 images is examined, with an exploration of how the choice of projection affects the inpainting result. Finally, the latter technique is shown to work for video in certain situations

Investigating the perceived strengths and limitations of Free-Viewpoint Video (FVV)

Free-viewpoint video (FVV) is a type of immersive content in which a character performance is filmed using an array of cameras and processed into a video-textured, animated 3D mesh. Although FVV content has a unique set of properties that differentiates it from other immersive media types, relatively little work explores the user experience of such content. As a preliminary investigation, we adopted an open-ended, qualitative approach to investigate these issues. Semi-structured interviews were conducted with six immersive content experts, exploring the perceived strengths and limitations of FVV as a content type. These interviews were analyzed using inductive thematic analysis. We identified five themes during our analysis: they don't look real, but that's okay; they can really move; they don't connect with me; encounter, legacy, and truth; no technology is an island. Our analysis reveals a wide range of future research directions and provides insight into which areas may produce the most benefit in relation to the user experience. We discuss, for example, the potential impact of difficulties in supporting user engagement, aspects related to visual quality such as the importance of responding realistically to environment lighting, and tensions between visual and behavioral quality. The analysis also highlights the complex interplay of factors related to the content itself, such as performance style and the use of creative production techniques to reduce the impact of potential limitations

Perception of volumetric characters' eye-gaze direction in head-mounted displays

Volumetric capture allows the creation of near-video-quality content that can be explored with six degrees of freedom. Due to limitations in these experiences, such as the content being fixed at the point of filming, an understanding of eye-gaze awareness is critical. A repeated-measures experiment was conducted that explored users’ ability to evaluate where a volumetrically captured avatar (VCA) was looking. Wearing one of two head-mounted displays (HMDs), 36 participants rotated a VCA to look at a target. The HMD resolution, target position, and VCA’s eye-gaze direction were varied. Results did not show a difference in accuracy between HMD resolutions, while the task became significantly harder for target locations further away from the user. In contrast to real-world studies, participants consistently misjudged eye-gaze direction based on target location, but not based on the avatar’s head turn direction. Implications are discussed, as results for VCAs viewed in HMDs appear to differ from face-to-face scenarios

Improving Free-Viewpoint Video content production using RGB-camera-based skeletal tracking

Free-Viewpoint Video (FVV) is a type of volumetric content in which an animated, video-textured 3D mesh of a character performance is constructed using data from an array of cameras. Previous work has demonstrated excellent results when creating motion graphs from FVV content, but these techniques are often prohibitively expensive in practice. We propose the use of skeletons to identify cut points between FVV clips, allowing a minimal set of frames to be processed into a 3D mesh. While our method performed with 2.8% poorer accuracy than the state-of-the-art for our synthetic dataset, cost and processing time requirements are dramatically reduced

The effect of transition type in multi-view 360 media

360-degree images and video have become extremely popular formats for immersive displays, due in large part to the technical ease of content production. While many experiences use a single camera viewpoint, an increasing number of experiences use multiple camera locations. In such multi-view 360-degree media (MV360M) systems, a visual effect is required when the user transitions from one camera location to another. This effect can take several forms, such as a cut or an image-based warp, and the choice of effect may impact many aspects of the experience, including issues related to enjoyment and scene understanding. To investigate the effect of transition types on immersive MV360M experiences, a repeated-measures experiment was conducted with 31 participants. Wearing a head-mounted display, participants explored four static scenes, for which multiple 360-degree images and a reconstructed 3D model were available. Three transition types were examined: teleport, a linear move through a 3D model of the scene, and an image-based transition using a Mobius transformation. The metrics investigated included spatial awareness, users’ movement profiles, transition preference and the subjective feeling of moving through the space. Results indicate that there was no significant difference between transition types in terms of spatial awareness, while significant differences were found for users’ movement profiles, with participants taking 1.6 seconds longer to select their next location following a teleport transition. The model and Mobius transitions were significantly better in terms of creating the feeling of moving through the space. Preference was also significantly different, with model and teleport transitions being preferred over Mobius transitions. Our results indicate that trade-offs between transitions will require content creators to think carefully about what aspects they consider to be most important when producing MV360M experiences

Torrefied fuel pellets from solid waste of sugar industry

The preparation of fuel pellets from the filter cake waste from the sugar industry was studied. Pelletization by a hydraulic press at a pressure of 20 to 50 bar (2 to 5 MPa) was used to produce fuel pellets with a diameter of 1 cm and height of 1. 25 cm. Energy efficiency of the resulting pellets was improved by thermal treatment called “torrefaction”. During this process, the samples were heated to between 200 and 300°C for 0.5 to 2 h under a nitrogen atmosphere. The properties of fuel pellets including calorific value, bulk density, pellet density, proximate analysis, and compressive strength were characterized. The results demonstrated that the minimum pressure needed to produce the pellets without binder was 30 bar. The calorific value was between 13,954–14,468 kJ/ kg for the resulting fuel pellet, which was significantly higher than that of the unpelletized raw material (11,197 kJ/ kg). The fuel pellets had bulk density and pellet density of between 300–440 kg/m3 and 720–890 kg/m3, respectively. Increasing the time and temperature of torrefaction resulted in the lower yields of pellets. Fuel pellets maintain their shape and did not break under the applied torrefaction conditions. Torrefied pellets resulted in higher calorific value of 16,552–22,642 kJ/kg, higher carbon content, lower pellet and bulk densities compared to the fuel pellet without thermal treatment. The compressive strength of torrefied pellets decreased due to the delicate nature of the sample. The suggested conditions for optimal torrefied pellet in thermal and physical properties are 300°C and 1 h. The prepared fuel pellets showed comparable heating values to other fuels, and had properties in agreement with Thailand standards. Therefore, filter cake as a solid waste from production process of sugar has potential as raw material for the production of solid fuel pellets

Directing versus attracting attention: exploring the effectiveness of central and peripheral cues in panoramic videos

Filmmakers of panoramic videos frequently struggle to guide attention to Regions of Interest (ROIs) due to consumers’ freedom to explore. Some researchers hypothesize that peripheral cues attract reflexive/involuntary attention whereas cues within central vision engage and direct voluntary attention. This mixed-methods study evaluated the effectiveness of using central arrows and peripheral flickers to guide and focus attention in panoramic videos. Twenty-five adults wore a head-mounted display with an eye tracker and were guided to 14 ROIs in two panoramic videos. No significant differences emerged in regard to the number of followed cues, the time taken to reach and observe ROIs, ROI-related memory and user engagement. However, participants’ gaze travelled a significantly greater distance toward ROIs within the first 500 ms after flicker-onsets compared to arrow-onsets. Nevertheless, most users preferred the arrow and perceived it as significantly more rewarding than the flicker. The findings imply that traditional attention paradigms are not entirely applicable to panoramic videos, as peripheral cues appear to engage both involuntary and voluntary attention. Theoretical and practical implications as well as limitations are discussed

Synthesis and application of tuneable carbon-silica composites from the microwave pyrolysis of waste paper for selective recovery of gold from acidic solutions

Microwave pyrolysis bio-oil from waste paper and K60 silica gel has successfully been utilised to synthesise mesoporous carbon-silica composites with uniquely tuneable surface properties, where functionality and structural characteristics can be altered and even enhanced by curing at different temperatures. This temperature-dependence resulted in composites ranging from highly oxygenated polymerised bio-oil composites at 300 °C to aromatic carbonaceous materials covering the silica surface at 800 °C, making them attractive materials for gold recovery from mining wastewater. The composite materials exhibit exceptional ability and selectivity to recover gold from dilute solutions. Metal adsorption on the surface of these composites proceeded via both chemisorption and physisorption leading to the reduction of Au(iii) to Au(0), resulting in high recovery capacities for gold. Composite material prepared at 500 °C demonstrated the optimum combination of surface functionality and porosity, allowing for an adsorption capacity of 320 mg g-1 of gold and with 99.5% removal being achieved at concentrations mimicking those of real-life mine tailing wastes. All materials pioneered in this research display great potential as selective adsorbents for the recovery of gold from acidic media. This journal i

The effect of chair type on users' viewing experience for 360-degree video

The consumption of 360-degree videos with head-mounted displays (HMDs) is increasing rapidly. A large number of HMD users watch 360-degree videos at home, often on non-swivel seats; however videos are frequently designed to require the user to turn around. This work explores how the difference in users’ chair type might influence their viewing experience. A between-subject experiment was conducted with 41 participants. Three chair conditions were used: fixed, half-swivel and full-swivel. A variety of measures were explored using eye-tracking, questionnaires, tasks and semi-structured interviews. Results suggest that the fixed and half-swivel chairs discouraged exploration for certain videos compared with the full-swivel chair. Additionally, participants in the fixed chair had worse spatial awareness and greater concern about missing something for certain video than those in the full-swivel chair. No significant differences were found in terms of incidental memory, general engagement and simulator sickness among the three chair conditions. Furthermore, thematic analysis of post-experiment interviews revealed four themes regarding the restrictive chairs: physical discomfort, difficulty following moving objects, reduced orientation and guided attention. Based on the findings, practical implications, limitations and future work are discussed