Video based reconstruction system for mixed reality environments supporting contextualised non-verbal communication and its study

This Thesis presents a system to capture, reconstruct and render the three-dimensional form of people and objects of interest in such detail that the spatial and visual aspects of non-verbal behaviour can be communicated.The system supports live distribution and simultaneous rendering in multiple locations enabling the apparent teleportation of people and objects. Additionally, the system allows for the recording of live sessions and their playback in natural time with free-viewpoint.It utilises components of a video based reconstruction and a distributed video implementation to create an end-to-end system that can operate in real-time and on commodity hardware.The research addresses the specific challenges of spatial and colour calibration, segmentation and overall system architecture to overcome technical barriers, the requirement of domain specific knowledge to setup and generate avatars to a consistent high quality.Applications of the system include, but are not limited to, telepresence, where the computer generated avatars used in Immersive Collaborative Virtual Environments can be replaced with ones that are faithful of the people they represent and supporting researchers in their study of human communication such as gaze, inter-personal distance and facial expression.The system has been adopted in other research projects and is integrated with a mixed reality application where, during a live linkup, a three-dimensional avatar is streamed to multiple end-points across different countries

A mixed reality telepresence system for collaborative space operation

This paper presents a Mixed Reality system that results from the integration of a telepresence system and an application to improve collaborative space exploration. The system combines free viewpoint video with immersive projection technology to support non-verbal communication, including eye gaze, inter-personal distance and facial expression. Importantly, these can be interpreted together as people move around the simulation, maintaining natural social distance. The application is a simulation of Mars, within which the collaborators must come to agreement over, for example, where the Rover should land and go. The first contribution is the creation of a Mixed Reality system supporting contextualization of non-verbal communication. Tw technological contributions are prototyping a technique to subtract a person from a background that may contain physical objects and/or moving images, and a light weight texturing method for multi-view rendering which provides balance in terms of visual and temporal quality. A practical contribution is the demonstration of pragmatic approaches to sharing space between display systems of distinct levels of immersion. A research tool contribution is a system that allows comparison of conventional authored and video based reconstructed avatars, within an environment that encourages exploration and social interaction. Aspects of system quality, including the communication of facial expression and end-to-end latency are reported

R squared effect-size measures and overlap between direct and indirect effect in mediation analysis

In a recent article in this journal (Fairchild, MacKinnon, Taborga & Taylor, 2009), a method was described for computing the variance accounted for by the direct effect and the indirect effect in mediation analysis. However, application of this method leads to counterintuitive results, most notably that in some situations in which the direct effect is much stronger than the indirect effect, the latter appears to explain much more variance than the former. The explanation for this is that the Fairchild et al. method handles the strong interdependence of the direct and indirect effect in a way that assigns all overlap variance to the indirect effect. Two approaches for handling this overlap are discussed, but none of them is without disadvantages

With you – an experimental end-to-end telepresence system using video-based reconstruction

We introduce withyou, our telepresence research platform. A systematic explanation of the theory brings together the linked nature of non-verbal communication and how it is influenced by technology. This leads to functional requirements for telepresence, in terms of the balance of visual, spatial and temporal qualities. The first end-to-end description of withyou describes all major processes and the display and capture environment. This includes two approaches to reconstructing the human form in 3D, from live video. An unprecedented characterization of our approach is given in terms of the above qualities, and influences of approach. This leads to non-functional requirements in terms of number and place of cameras and the avoidance of a resultant bottlekneck. Proposals are given for improved distribution of processes across networks, computers, and multi-core CPU and GPU. Simple conservative estimation shows that both approaches should meet our requirements. One is implemented and shown to meet minimum and come close to desirable requirements

Sex differences in risk-based decision making in adolescents with conduct disorder

Altered decision making processes and excessive risk-seeking behaviours are key features of conduct disorder (CD). Previous studies have provided compelling evidence of abnormally increased preference for risky options, higher sensitivity to rewards, as well as blunted responsiveness to aversive outcomes in adolescents with CD. However, most studies published to date have focused on males only; thus, it is not known whether females with CD show similar alterations in decision making. The current study investigated potential sex differences in decision making and risk-seeking behaviours in adolescents with CD. Forty-nine adolescents with CD (23 females) and 51 control subjects (27 females), aged 11-18 years, performed a computerised task assessing decision making under risk—the Risky Choice Task. Participants made a series of decisions between two gamble options that varied in terms of their expected values and probability of gains and losses. This enabled the participants’ risk preferences to be determined. Taking the sample as a whole, adolescents with CD exhibited increased risk-seeking behaviours compared to healthy controls. However, we found a trend towards a sex-by-group interaction, suggesting that these effects may vary by sex. Follow-up analyses showed that males with CD made significantly more risky choices than their typically developing counterparts, while females with CD did not differ from typically developing females in their risk-seeking behaviours. Our results provide preliminary evidence that sex may moderate the relationship between CD and alterations in risk attitudes and reward processing, indicating that there may be sex differences in the developmental pathways and neuropsychological deficits that lead to CD

Responsibility loadings for dental services by general dentists

Extent: 6p.BACKGROUND: Responsibility loadings determine relative value units of dental services that translate services into a common scale of work effort. The aims of this paper were to elicit responsibility loadings for a subset of dental services and to relate responsibility loadings to ratings of importance of the components of responsibility. METHODS: Responsibility loadings and ratings of components of responsibility were collected using mailed questionnaires from a random sample of Australian private general practice dentists in 2007 (response rate = 77%). RESULTS: Median responsibility loadings were 1.25 for an initial oral examination and for a 3+-surface amalgam restoration, 1.50 for a simple extraction and for root canal obturation (single canal), and 1.75 for subgingival curettage (per quadrant). Across the five services coefficients from a multivariate logit model showed that ratings of importance of knowledge (0.34), dexterity (0.24), physical effort (0.28) and mental effort (0.48) were associated with responsibility loadings (P < 0.05). CONCLUSIONS: The elicited median responsibility loadings showed agreement with previous estimates indicating convergent validity. Components of responsibility were associated with loadings indicating that components can explain and predict responsibility aspects of dental service provision.David S. Brennan and A. John Spence