For efficient navigational search, humans require full physical movement but not a rich visual scene

During navigation, humans combine visual information from their surroundings with body-based information from the translational and rotational components of movement. Theories of navigation focus on the role of visual and rotational body-based information, even though experimental evidence shows they are not sufficient for complex spatial tasks. To investigate the contribution of all three sources of information, we asked participants to search a computer generated “virtual” room for targets. Participants were provided with either only visual information, or visual supplemented with body-based information for all movement (walk group) or rotational movement (rotate group). The walk group performed the task with near-perfect efficiency, irrespective of whether a rich or impoverished visual scene was provided. The visual-only and rotate groups were significantly less efficient, and frequently searched parts of the room at least twice. This suggests full physical movement plays a critical role in navigational search, but only moderate visual detail is required

Implementing flexible rules of interaction for object manipulation in cluttered virtual environments

Object manipulation in cluttered virtual environments (VEs) brings additional challenges to the design of interaction algorithms, when compared with open virtual spaces. As the complexity of the algorithms increases so does the flexibility with which users can interact, but this is at the expense of much greater difficulties in implementation for developers. Three rules that increase the realism and flexibility of interaction are outlined: collision response, order of control, and physical compatibility. The implementation of each is described, highlighting the substantial increase in algorithm complexity that arises. Data are reported from an experiment in which participants manipulated a bulky virtual object through parts of a virtual building (the piano movers’ problem). These data illustrate the benefits to users that accrue from implementing flexible rules of interaction

Full Body Acting Rehearsal in a Networked Virtual Environment-A Case Study

In order to rehearse for a play or a scene from a movie, it is generally required that the actors are physically present at the same time in the same place. In this paper we present an example and experience of a full body motion shared virtual environment (SVE) for rehearsal. The system allows actors and directors to meet in an SVE in order to rehearse scenes for a play or a movie, that is, to perform some dialogue and blocking (positions, movements, and displacements of actors in the scene) rehearsal through a full body interactive virtual reality (VR) system. The system combines immersive VR rendering techniques as well as network capabilities together with full body tracking. Two actors and a director rehearsed from separate locations. One actor and the director were in London (located in separate rooms) while the second actor was in Barcelona. The Barcelona actor used a wide field-of-view head-tracked head-mounted display, and wore a body suit for real-time motion capture and display. The London actor was in a Cave system, with head and partial body tracking. Each actor was presented to the other as an avatar in the shared virtual environment, and the director could see the whole scenario on a desktop display, and intervene by voice commands. A video stream in a window displayed in the virtual environment also represented the director. The London participant was a professional actor, who afterward commented on the utility of the system for acting rehearsal. It was concluded that full body tracking and corresponding real-time display of all the actors' movements would be a critical requirement, and that blocking was possible down to the level of detail of gestures. Details of the implementation, actors, and director experiences are provided

Towards Naturalistic Interfaces of Virtual Reality Systems

Interaction plays a key role in achieving realistic experience in virtual reality (VR). Its realization depends on interpreting the intents of human motions to give inputs to VR systems. Thus, understanding human motion from the computational perspective is essential to the design of naturalistic interfaces for VR. This dissertation studied three types of human motions, including locomotion (walking), head motion and hand motion in the context of VR. For locomotion, the dissertation presented a machine learning approach for developing a mechanical repositioning technique based on a 1-D treadmill for interacting with a unique new large-scale projective display, called the Wide-Field Immersive Stereoscopic Environment (WISE). The usability of the proposed approach was assessed through a novel user study that asked participants to pursue a rolling ball at variable speed in a virtual scene. In addition, the dissertation studied the role of stereopsis in avoiding virtual obstacles while walking by asking participants to step over obstacles and gaps under both stereoscopic and non-stereoscopic viewing conditions in VR experiments. In terms of head motion, the dissertation presented a head gesture interface for interaction in VR that recognizes real-time head gestures on head-mounted displays (HMDs) using Cascaded Hidden Markov Models. Two experiments were conducted to evaluate the proposed approach. The first assessed its offline classification performance while the second estimated the latency of the algorithm to recognize head gestures. The dissertation also conducted a user study that investigated the effects of visual and control latency on teleoperation of a quadcopter using head motion tracked by a head-mounted display. As part of the study, a method for objectively estimating the end-to-end latency in HMDs was presented. For hand motion, the dissertation presented an approach that recognizes dynamic hand gestures to implement a hand gesture interface for VR based on a static head gesture recognition algorithm. The proposed algorithm was evaluated offline in terms of its classification performance. A user study was conducted to compare the performance and the usability of the head gesture interface, the hand gesture interface and a conventional gamepad interface for answering Yes/No questions in VR. Overall, the dissertation has two main contributions towards the improvement of naturalism of interaction in VR systems. Firstly, the interaction techniques presented in the dissertation can be directly integrated into existing VR systems offering more choices for interaction to end users of VR technology. Secondly, the results of the user studies of the presented VR interfaces in the dissertation also serve as guidelines to VR researchers and engineers for designing future VR systems

Dynamic urban projection mapping

“Dynamic projection mapping” is a variation of the best-known “projection mapping”. It considers the perceptual analysis of the urban landscape in which the video projection and the observer’s displacement speed are hypothesized. This latter, in particular, is variable and may depend on factors not directly controllable by the driver (slowdowns due to accidents, rallies, etc.). This speed can be supported and controlled by a number of traffic flow measurement systems. These data are available on the internet, like Google Maps APIs and/or speed sensors located close to the point of interest. The content of projection becomes dynamic and varies according to how the observer perceives the vehicle: slow, medium, fast