What We Measure in Mixed Reality Experiments

There are many potential measures that one might use when evaluating mixed-reality experiences. In this position paper I will argue that there are various stances to take for evaluation, depending on the framing of the experience within a larger body of work. I will draw upon various types of work that my team has been involved with in order to illustrate these different stances. I will then sketch out some directions for developing more robust measures that can help the field move forward

Defining Interaction within Immersive Virtual Environments

PhDThis thesis is concerned with the design of Virtual Environments (YEs) - in particular with the tools and techniques used to describe interesting and useful environments. This concern is not only with respect to the appearance of objects in the VE but also with their behaviours and their reactions to actions of the participants. The main research hypothesis is that there are several advantages to constructing these interactions and behaviours whilst remaining immersed within the VE which they describe. These advantages include the fact that editing is done interactively with immediate effect and without having to resort to the usual edit-compile-test cycle. This means that the participant doesn't have to leave the VE and lose their sense of presence within it, and editing tasks can take advantage of the enhanced spatial cognition and naturalistic interaction metaphors a VE provides. To this end a data flow dialogue architecture with an immersive virtual environment presentation system was designed and built. The data flow consists of streams of data that originate at sensors that register the body state of the participant, flowing through filters that modify the streams and affect the yE. The requirements for such a system and the filters it should contain are derived from two pieces of work on interaction metaphors, one based on a desktop system using a novel input device and the second a navigation technique for an immersive system. The analysis of these metaphors highlighted particular tasks that such a virtual environment dialogue architecture (VEDA) system might be used to solve, and illustrate the scope of interactions that should be accommodated. Initial evaluation of the VEDA system is provided by moderately sized demonstration environments and tools constructed by the author. Further evaluation is provided by an in-depth study where three novice VE designers were invited to construct VEs with the VEDA system. This highlighted the flexibility that the VEDA approach provides and the utility of the immersive presentation over traditional techniques in that it allows the participant to use more natural and expressive techniques in the construction process. In other words the evaluation shows how the immersive facilities of VEs can be exploited in the process of constructing further VEs

Defining Interaction within Immersive Virtual Environments

Submitted to the University of London for the degree of Doctor of Philosophy in Computer Scienc

Effectiveness of Social Virtual Reality

A lot of work in social virtual reality, including our own group's, has focused on effectiveness of specific social behaviours such as eye-gaze, turn taking, gestures and other verbal and non-verbal cues. We have built upon these to look at emergent phenomena such as co-presence, leadership and trust. These give us good information about the usability issues of specific social VR systems, but they don't give us much information about the requirements for such systems going forward. In this short paper we discuss how we are broadening the scope of our work on social systems, to move out of the laboratory to more ecologically valid situations and to study groups using social VR for longer periods of time

Exploring User Behaviour in Asymmetric Collaborative Mixed Reality

A common issue for collaborative mixed reality is the asymmetry of interaction with the shared virtual environment. For example, an augmented reality (AR) user might use one type of head-mounted display (HMD) in a physical environment, while a virtual reality (VR) user might wear a different type of HMD and see a virtual model of that physical environment. To explore the effects of such asymmetric interfaces on collaboration we present a study that investigates the behaviour of dyads performing a word puzzle task where one uses AR and the other VR. We examined the collaborative process through questionnaires and behavioural measures based on positional and audio data. We identified relationships between presence and co-presence, accord and co-presence, leadership and talkativeness, head rotation velocity and leadership, and head rotation velocity and talkativeness. We did not find that AR or VR biased subjective responses, though there were interesting behavioural differences: AR users spoke more words, AR users had a higher median head rotation velocity, and VR users travelled further

Tomato Presence: Virtual Hand Ownership with a Disappearing Hand

Tomato presence is a term coined by Owlchemy Labs to refer to the observation that players of their game Job Simulator can experience `hand presence' over an object that is not their hand. When playing the game, if a player grabs an object, their virtual hand disappears leaving the grabbed object. While players still observe a direct proprioceptive match between their hand movements and the object being manipulated, it seems that there should be a conflict with current theories of how users might react to visual/proprioceptive mismatch of their embodiment. We run a hand ownership experiment where we implement standard object grasp and the disappearing hand grasp. We show that on a body-ownership questionnaire there is evidence to support the notion that users still feel ownership over a virtual hand even though it is periodically disappearing. We also confirm that most users do not report that their hand disappeared

Constructing a gazebo: supporting teamwork in a tightly coupled, distributed task in virtual reality

Many tasks require teamwork. Team members may work concurrently, but there must be some occasions of coming together. Collaborative virtual environments (CVEs) allow distributed teams to come together across distance to share a task. Studies of CVE systems have tended to focus on the sense of presence or copresence with other people. They have avoided studying close interaction between us-ers, such as the shared manipulation of objects, because CVEs suffer from inherent network delays and often have cumbersome user interfaces. Little is known about the ef-fectiveness of collaboration in tasks requiring various forms of object sharing and, in particular, the concurrent manipu-lation of objects. This paper investigates the effectiveness of supporting teamwork among a geographically distributed group in a task that requires the shared manipulation of objects. To complete the task, users must share objects through con-current manipulation of both the same and distinct at-tributes. The effectiveness of teamwork is measured in terms of time taken to achieve each step, as well as the impression of users. The effect of interface is examined by comparing various combinations of walk-in cubic immersive projection technology (IPT) displays and desktop devices

Developing an Accessibility Metric for VR Games Based on Motion Data Captured Under Game Conditions

Virtual Reality (VR) games are not as accessible as conventional video games because they heavily rely on the motion of the body as the main means of input. This causes large accessibility issues because it prevents some physically impaired players from using them. It also makes it more difficult to develop accessibility tools to address the issues. Given these challenges, it is of particular importance that an impaired player can determine whether they will be able to play a game before they buy it. We propose the first prototype of a metric that aims at visually presenting the important aspects of the body motion that a game requires. Instead of manual classification, the metric is based on data captured from able-bodied players that play the game as designed. In this work, we introduce the metric itself, demonstrate how it differentiates six popular VR games based on data we collected in a user study, and discuss limitations and routes for further development

Monte-Carlo Redirected Walking: Gain Selection Through Simulated Walks

We present Monte-Carlo Redirected Walking (MCRDW), a gain selection algorithm for redirected walking. MCRDW applies the Monte-Carlo method to redirected walking by simulating a large number of simple virtual walks, then inversely applying redirection to the virtual paths. Different gain levels and directions are applied, producing differing physical paths. Each physical path is scored and the results used to select the best gain level and direction. We provide a simple example implementation and a simulation-based study for validation. In our study, when compared with the next best technique, MCRDW reduced incidence of boundary collisions by over 50% while reducing total rotation and position gain