Virtual Cultural Identities

Virtual environments and the Internet provide an important medium for interactive collaborative learning. Immersive Virtual Environments appear able to support intuitive interaction techniques and metaphors. Our Identity Authoring Approach is aimed at our multicultural global society, and allows for multiple identities / persona to be created and used as interaction metaphors by users. The approach can be used to generate virtual environments in which the interaction is both intuitive and adaptable to the cultural background of the user, taking into account issues such as gendered and age-based identities. The approach is exemplified by focusing on interaction in virtual learning environments that engage and facilitate the introduction and experience of different cultures, by different users

A device-free locator using computer vision techniques

Device-free locators allow the user to interact with a system without the burden of being physically in contact with some input device or without being connected to the system with cables. This thesis presents a device-free locator that uses computer vision techniques to recognize and track the user's hand. The system described herein uses a video camera to capture live video images of the user, which are segmented and processed to extract features that can be used to locate the user's hand within the image. Two types of features, namely moment based invariants and Fourier descriptors, are compared experimentally. An important property of both these techniques is that they allow the recognition of hand-shapes regardless of affine transformation, e.g. rotation within the plane or scale changes. A neural network is used to classify the extracted features as belonging to one of several hand signals, which can be used in the locator system as 'button clicks' or mode indicators. The Siltrack system described herein illustrates that the above techniques can be implemented in real-time on standard hardware.Dissertation (MSc (Computer Science))--University of Pretoria, 2007.Computer Scienceunrestricte

Virtual meeting in cyberstage

Today’s technology and advances in networking and telecommunications stimulate a change in the way business is carried out, making it a globally distributed process, in which communication and collaboration of geographically dispersed groups is of vital importance. Virtual Reality systems are adapting accordingly, by providing not only a better man-machine interface, but also by facilitating human to human interaction and collaboration over distance. The approach presented in this paper, creates an environment where remote participants not only meet as if face to face, but also share the same virtual space and perform common tasks. Live stereo-video and audio, from a projectionbased VR system are transmitted and integrated into the virtual space of another participant at a distant VR system, allowing geographically separated groups to meet in a common virtual space, while maintaining eyecontact, gaze awareness and body language. The scientific approach involves stereo-camera calibration and rectification, and use of the camera parameters for integrating the stereovideo into a virtual environment, while maintaining the stereo-effect and correct perspective for each participant. A prototype environment in CyberStage, is also presented in detail in this paper. Virtual Reality is widely accepted as a promising approach to a better man-machine interface, overcoming the present limitations of desktop systems and adapting more closely to the user needs. Projection-based VR systems are using metaphors, such as the blackboard or the desk for creating shared working environments that provide a more natural man-machine communication. Today’s technology and advances in telecommunications lead to sophisticated multimedia systems which combined with virtual reality can provide a high degree of co-presence and co-working for geographically dispersed groups. Therefore, new challenges are introduced in terms of multimedia integration in distributed virtual reality environments and interaction. It is not only a question of solving the technical problems of gathering and transmitting multimedia datastreams with sufficient quality and speed, but also a question of addressing the specific needs of human communication. For example, facial expression, body language and eye contact are an integral part of this communicatio