A common measure of the quality or effectiveness of a virtual environment (VE) is the amount of presence it evokes in users. Presence is often defined as the sense of being there in a VE. There has been much debate about the best way to measure presence, and presence researchers need, and have sought, a measure that is reliable, valid, sensitive, and objective. We hypothesized that to the degree that a VE seems real, it would evoke physiological responses similar to those evoked by the corresponding real environment, and that greater presence would evoke a greater response. To examine this, we conducted three experiments, the results of which support the use of physiological reaction as a reliable, valid, sensitive, and objective presence measure. The experiments compared participants ’ physiological reactions to a non-threatening virtual room and their reactions to a stressful virtual height situation. We found that change in heart rate satisfied our requirements for a measure of presence, change in skin conductance did to a lesser extent, and that change in skin temperature did not. Moreover, the results showed that inclusion of a passive haptic element in the VE significantly increased presence and that for presence evoked: 30FPS> 20FPS> 15FPS. Categories: I.3.7 [Computer Graphics]: Three-Dimensional

Since the early 1980s, the Tracker Project at the University of North Carolina at Chapel Hill has been working on wide-area head tracking for virtual and augmented environments. Our long-term goal has been to achieve the high performance required for accurate visual simulation throughout our entire laboratory, beyond into the hallways, and eventually even outdoors. In this article, we present results and a complete description of our most recent electro-optical system, the HiBall Tracking System. In particular, we discuss motivation for the geometric configuration and describe the novel optical, mechanical, electronic, and algorithmic aspects that enable unprecedented speed, resolution, accuracy, robustness, and flexibility.

Redirected Walking, a new interactive locomotion technique for virtual environments (VEs), captures the benefits of real walking while extending the possible size of the VE. Real walking, although natural and producing a high subjective sense of presence, limits virtual environments to the size of the tracked space. Redirected Walking addresses this limitation by interactively and imperceptibly rotating the virtual scene about the user. The rotation causes the user to walk continually toward the furthest wall of the lab without noticing the rotation. We implemented the technique using stereo graphics and 3D spatialized audio. Observations during a pilot study suggest that the technique works: Redirected Walking causes people to change their real walking direction without noticing it, allows for larger VEs, and does not induce appreciable simulator sickness. 1.

This paper describes a new measure for presence in immersive virtual environments (VEs) based on data that can be obtained unobtrusively during the course of a VE experience. At different times during an experience a participant will occasionally switch between interpreting the totality of sensory inputs as forming the VE or the real world. The number of transitions from virtual to real is counted, and using some simplifying assumptions, a probabilistic Markov Chain model can be constructed to model these transitions. This can be used to estimate the equilibrium probability of being `present' in the VE. This technique was applied in the context of an experiment to assess the relationship between presence and body movement in an immersive VE. The movement was that required by subjects to reach out and touch successive pieces on a Tri-Dimensional chess board. The experiment included 20 subjects, 10 of whom had to reach out to touch the chess pieces (`active group'), and the other 10 con...

Virtual environments (VEs) that use a real-walking locomotion interface have typically been restricted in size to the area of the tracked lab space. Techniques proposed to lift this size constraint, enabling real walking in VEs that are larger than the tracked lab space, all require reorientation techniques (ROTs) in the worst-case situation–when a user is close to walking out of the tracked space. We propose a new ROT using distractors–objects in the VE for the user to focus on while the VE rotates—and compare our method to current ROTs through two user studies. Our findings show ROTs using distractors were preferred and ranked more natural by users. Users were also less aware of the rotating VE when ROTs with distractors were used.

Walking-in-place techniques for locomotion in virtual environments typically have two problems that impact their usability: system latency (particularly troublesome when starting and stopping locomotion), and the fact that the change in the user’s viewpoint may not be smooth and continuous. This paper describes a new WIP interface that improves both latency and the continuity of synthesized locomotion in the virtual environment. By basing the virtual avatar motion on the speed of the user’s heel motion while walking in place, we create a direct mapping from foot-motion to locomotion that is responsive, intuitive, and easy to implement. In this paper, we describe the technique, analyze its starting and stopping latency, and provide experimental results on the suppression of false steps and general usability of the system.

Virtual environments (VEs) are one of the most advanced human-computer interface to date. A common measure of the effectiveness of a VE is the amount of presence it evokes in users. Presence is commonly defined as the sense of being there in a VE. In order to study the effect that technological improvements such as higher frame rate, more visual realism, and lower lag have on presence, we must be able to measure it. There has been much debate about the best way to measure presence, and we, as presence researchers, have yearned for a measure that is Reliable — produces repeatable results, both from trial to trial on the same subject and across subjects; Valid — measures subjective presence, or at least correlates well with established subjective presence measures; Sensitive — is capable of distinguishing multiple levels of presence; and Objective — is well shielded from both subject bias and experimenter bias. We hypothesize that to the degree that a VE seems real, it will evoke physiological responses similar to those evoked by the corresponding real environment, and that greater presence will evoke a greater response. Hence, these responses serve as reliable, valid, sensitive, and objective measures of presence. We conducted three experiments that support the use of physiological reaction as a reliable, valid,

We present a novel approach for interactive navigation in complex 3D synthetic environments using path planning. Our algorithm precomputes a global roadmap of the environment by using a variant of randomized motion planning algorithm along with a reachability-based analysis. At runtime, our algorithm performs graph searching and automatically computes a collision-free and constrained path between two user specified locations. It also enables local user-steered exploration, subject to motion constraints and integrates these capabilities in the control loop of 3D interaction. Our algorithm only requires the scene geometry, avatar orientation, and parameters relating the avatar size to the model size. The performance of the preprocessing algorithm grows as a linear function of the model size. We demonstrate its performance on two large environments: a power plant and a factory room.

Navigating through large virtual environments using a headmounted display (HMD) is difficult due to the spatial limitations of the tracking system. We conducted two experiments to examine methods of exploring large virtual spaces with an HMD under translation conditions different than normal walking. Experiment 1 compares locomotion in the virtual environment using two different motor actions to translate the subject. The study contrasts user learning and orientation of two different translational gains of bipedal locomotion (not scaled and scaled by ten) with joystick locomotion, where rotation in both locomotion interfaces is accomplished by physically turning. Experiment 2 looks further at the effects of increasing the translational gain of bipedal locomotion in a virtual environment. A subject’s spatial learning and orientation were evaluated in three gain conditions where each physical step was: not scaled, scaled by two, or scaled by ten (1:1, 2:1, 10:1, respectively). A sub-study of this experiment compared the performance of people who played video games against people who did not.

When collaborating individuals rely on situation awareness (the gathering, incorporation and utilization of environmental information) to help them combine their unique knowledge and skills and achieve their goals. When collaborating across distances, situation awareness is mediated by technology. There are few guidelines to help system analysts design systems or applications that support the creation and maintenance of situation awareness for teams or groups. We propose a framework to guide design decisions to enhance computer-mediated situation awareness during scientific research collaboration. The foundation for this framework is previous research in situation awareness and virtual reality, combined with our analysis of interviews and observations of collaborating scientists. The framework suggests that situation awareness is comprised of contextual, task and process, and socio-emotional information. Research in virtual reality systems suggests control, sensory, distraction and realism attributes of technology contribute to a sense of presence (Witmer & Singer, 1998). We suggest that consideration of these attributes with respect to contextual, task and process, and socio-emotional information provides insights to guide design decisions. We used the