Using 3D sound as a navigational aid in virtual environments

As current virtual environments are less visually rich than real-world environments, careful consideration must be given to their design to ameliorate the lack of visual cues. One important design criterion in this respect is to make certain that adequate navigational cues are incorporated into complex virtual worlds. In this paper we show that adding 3D spatialized sound to a virtual environment can help people navigate through it. We conducted an experiment to determine if the incorporation of 3D sound (a) helps people find specific locations in the environment, and (b) influences the extent to which people acquire spatial knowledge about their environment. Our results show that the addition of 3D sound did reduce time taken to locate objects in a complex environment. However, the addition of sound did not increase the amount of spatial knowledge users were able to acquire. In fact, the addition of 3D auditory sound cues appears to suppress the development of overall spatial knowledge of the virtual environment.     

Using bat-modelled sonar as a navigational tool in virtual environments

Bats are able to use active sonar as a mechanism for locating object in three dimensions and for generating spatial maps of their environments. Humans use passive sound cues to detect features of the space they occupy, as well as react to the spatial location of objects which generate sound. The system described in this paper allows free-ranging humans to locate a virtual sound location using active sonar. An emitted pulse, centred on the users head, serves as an intensity and time marker. The return pulse is rendered at the virtual target location and emitted after a time delay corresponding to the two-way path from sender to target and back again. The sonar system is modelled on those of bats, using ultrasonic frequency-modulated signals reflected from simple targets. The model uses the reflectivity characteristics of ultrasound, but the frequency and temporal structure used are scaled, with the speed of sound being set to 8.5 ms⁻¹ to bring the frequency range and temporal resolution within the capabilities of the human auditory system. Orientation with respect to the ensonified target is achieved by time-of-flight time delays to give target range, and binaural location information derived from interaural timing differences, interaural intensity differences, and head-related transfer functions. Subjects performed significantly better at a localization task when given temporal data based on echo delays with an outgoing reference pulse than without a reference pulse. Frequency-modulated signals sweeping from 1.5 kHz–100 Hz over 500 ms provide the best localization cues, and users found them significantly easier to locate than continuous sounds.     

Snake terrestrial locomotion synthesis in 3D virtual environments

We present a method for a 3D snake model construction and terrestrial snake locomotion synthesis in 3D virtual environments using image sequences. The snake skeleton is extracted and partitioned into equal segments using a new iterative algorithm for solving the equipartition problem. This method is applied to 3D model construction and at the motion analysis stage. Concerning the snake motion, the snake orientation is controlled by a path planning method. An animation synthesis algorithm, based on a physical motion model and tracking data from image sequences, describes the snake’s velocity and skeleton shape transitions. Moreover, the proposed motion planning algorithm allows a large number of skeleton shapes, providing a general method for aperiodic motion sequences synthesis in any motion graph. Finally, the snake locomotion is adapted to the 3D local ground, while its behavior can be easily controlled by the model parameters yielding the appropriate realistic animations.     

Teleporting through virtual environments: benefits of navigational feedback and practice

Virtual Reality - Virtual environments (VEs) can be infinitely large, but movement of the virtual reality (VR) user is constrained by the surrounding real environment. Teleporting has become a...     

Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine supported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization that models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occur when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, the present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was documentation for a word processing system. In the first experiment, the pathfinder algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expertbased semantic relationships between word-processing concepts. The results from these analyses contributed to the design of two prostheses to assist hypertext navigation: A hierarchical index and a local semantic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetically indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses improved the accessibility of information for novice users without hampering expert performance.     

Analyzing place metaphors in 3D educational collaborative virtual environments

In the recent years, the usage of three dimensional (3D) collaborative virtual environments (CVEs) for educational purposes has increased. The metaphors behind the design of virtual places are quite diverse, from replication of real universities to art museums and scientific labs. This paper reports the results of a case study where the students of our university, as a part of their course assignment, analyzed place metaphors used in a range of 3D educational CVEs vs. the corresponding educational goals. The students suggested a design for a virtual campus representing the Norwegian University of Science and Technology (NTNU). The results of this study provide some suggestions concerning the characterization of different design features in educational CVEs and the suitability of such features for different educational goals. Also, a preliminary set of design guidelines for an ideal virtual campus representing a real university is presented. Finally, some challenges associated with using 3D CVEs in various educational situations are discussed.     

Human knowledge acquisition from 3D interaction in virtual environments

Recently,virtual environment (VE) based design and planning,which is a kind of interaction intensive computing,has shown great potential.Most users of such systems are specialists or technicians and their 3D interactions with the system embed a great deal of knowledge and skills.Thus,how to integrate human knowledge and skills into VE is a great challenge to researchers in the human computer interaction field.This paper proposes a method for acquiring user knowledge from VE.The main ideas and work include,abstracting the interactive process and formalizing the interactive semantics,as well as providing a semantic model of an interactive information repository,from which user interactive processes can be retrieved and all kinds of application logics can be established.A virtual assembly planning system is introduced as an example of a practical application of this method.Experiments show that the related models can well capture user knowledge and retrieve the interaction process.     

Fully peer-to-peer virtual environments with 3D Voronoi diagrams

A fully peer-to-peer (P2P) virtual environment (VE) represents a unique challenge in the realm of extreme distributed systems. Resource scalability and system resiliency, hallmark requirements of the P2P principle, are further complicated with the need for secure and responsive game-play amongst the millions of players in a P2P-VE. Inter-peer communications need to be almost real-time in nature, to facilitate a smooth, immersive experience and provide consistency within the virtual world. Players will not tolerate slow connections and players who cheat by modifying or delaying inter-peer updates. 3D Voronoi diagrams are a natural extension to traditional 2D varieties and they serve as the foundation for our proposed approach. We augment our 3D-VD platform with a novel concept: the usual spatial coordinates for the 3rd dimension is substituted with a non-spatial metric. Instead of taking the Z-axis to literally mean above or below someone within the virtual map, we use it to signify a player’s current resource capabilities. This effectuates more fluid self-organisation amongst the millions of peers within the VE. Work-loads, consisting of resource intensive arbitration tasks, are handled dynamically at localised clusters. Thus, we have a strictly decentralised mechanism that addresses responsiveness and security concerns from the bottom up. Simulation results verify the feasibility and performance of our technique, with arbitration failure situations reduced significantly.     

Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine supported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization that models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occur when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, the present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was documentation for a word processing system. In the first experiment, the pathfinder algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expertbased semantic relationships between word-processing concepts. The results from these analyses contributed to the design of two prostheses to assist hypertext navigation: A hierarchical index and a local semantic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetically indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses improved the accessibility of information for novice users without hampering expert performance.     

Perceived enablers of 3D virtual environments for virtual team learning and innovation

Virtual teams consist of geographically distributed employees working with a common goal using mostly technology for communication and collaboration. Virtual teams face a number of challenges, discussed in the literature in terms of communication through technology, difficulty in building trust, conveying social cues, and creating awareness, as well as cultural differences. These challenges impact collaboration, but also learning and innovation. This research focuses on how a social medium, the 3D virtual environment, is perceived to enable learning and innovation in virtual teams. We study this through a qualitative study based on interviews of distributed work managers’ perception of VEs. The major findings are that VEs are perceived to create collaborative learning atmospheres for virtual teams in terms of enabling engagement, a shared context awareness, and support in social network building. Another finding is that VEs are perceived to enable team learning, knowledge development, and collaboration through persistence of content, information sharing, learning through role-plays and simulations, and visualization. Furthermore, VEs enable the development of co-created content as well as new ways of working in virtual teams.     

Dense and dynamic 3D selection for game-based virtual environments

3D object selection is more demanding when, 1) objects densly surround the target object, 2) the target object is significantly occluded, and 3) when the target object is dynamically changing location. Most 3D selection techniques and guidelines were developed and tested on static or mostly sparse environments. In contrast, games tend to incorporate densly packed and dynamic objects as part of their typical interaction. With the increasing popularity of 3D selection in games using hand gestures or motion controllers, our current understanding of 3D selection needs revision. We present a study that compared four different selection techniques under five different scenarios based on varying object density and motion dynamics. We utilized two existing techniques, Raycasting and SQUAD, and developed two variations of them, Zoom and Expand, using iterative design. Our results indicate that while Raycasting and SQUAD both have weaknesses in terms of speed and accuracy in dense and dynamic environments, by making small modifications to them (i.e., flavoring), we can achieve significant performance increases.     

3D sound interactive environments for blind children problem solving skills

Audio-based virtual environments have been increasingly used to foster cognitive and learning skills. A number of studies have also highlighted that the use of technology can help learners to develop effective skills such as motivation and self-esteem. This study presents the design and usability of 3D interactive environments for children with visual disabilities to help them solve problems in Chilean geography and culture. We introduce AudioChile, a virtual environment that can be navigated through 3D sound to enhance spatiality and immersion throughout the environment. 3D sound is used to orientate, avoid obstacles, and identify the positions of various characters and objects within the environment. We have found during the usability evaluation that sound can be fundamental for attention and motivation purposes during interaction. Learners identified and clearly discriminated environmental sounds to solve everyday problems, spatial orientation, and laterality.     

Using a preamble to increase presence in digital virtual environments

Immersion in a digital virtual environment (DVE) increases the likelihood that individuals will feel present in the DVE and hence respond as they would in a similar physically grounded environment. Previous research utilizing high-fidelity technology has demonstrated that by starting a virtual experience in a virtual replica of the immediate physical environment, presence is increased. The purpose of this study was to determine whether utilizing such a transitional environment to increase presence could be replicated on a significantly less immersive system—a 2D desktop monitor with mouse and keyboard for navigation. Participants began their DVE experience either in a “preamble” DVE made to look like the surrounding physical laboratory space, or in a novel DVE (i.e., a house). Then, they were given verbal instructions to leave their respective environments and told to go up a set of stairs to explore a museum. Afterward, they reported levels of immersion and presence in the latter DVE. Results demonstrated that entering a target DVE via a familiar “preamble” environment increased perceptions of reality judgment of the virtual experience, perceptions of possibility to act, and levels of presence. These results suggest that incorporating a familiar digital preamble environment as a prelude to the target DVE enables DVE designers and enthusiasts to increase presence without having to invest in more expensive hardware, but it could also augment existing immersive technology. Their efficacy may be because they offer a gradual transition into the virtual world, such that the familiarity eases users into the novel experience.     

Using virtual environments to train firefighters

Using virtual environments for training and mission rehearsal gives US Navy firefighters an edge in fighting real fires. A test run on the ex-USS Shadwell measured the improvement. The results suggest that virtual environments serve effectively for training and mission rehearsal for shipboard firefighting. VE training provides a flexible environment where a firefighter can not only learn an unfamiliar part of the ship, but also practice tactics and procedures for fighting a fire by interacting with simulated smoke and fire without risking lives or property. These tests proved a successful first step in developing a new training technology for shipboard firefighting based on immersive virtual environments. The tests also indicated potential areas for improvement, requiring additional research. User interaction techniques for manipulating objects in VEs need further study, along with usability studies to determine their effectiveness or utility. Other areas that could enhance VE training systems include more natural and intuitive I/O devices such as 3D sound, speech and natural language input, integrated multimedia and hypermedia instruction, and multi user interaction     

Multimodal interaction for 2D and 3D environments [virtual reality]

The allure of immersive technologies is undeniable. Unfortunately, the user's ability to interact with these environments lags behind the impressive visuals. In particular, it's difficult to navigate in unknown visual landscapes, find entities, access information and select entities using six-degrees-of-freedom (6-DOF) devices. We believe multimodal interaction-specifically speech and gesture-will make a major difference in the usability of such environments     

Evaluation of a low-cost 3D sound system for immersive virtual reality training systems

Since head mounted displays (HMD), datagloves, tracking systems, and powerful computer graphics resources are nowadays in an affordable price range, the usage of PC-based "virtual training systems" becomes very attractive. However, due to the limited field of view of HMD devices, additional modalities have to be provided to benefit from 3D environments. A 3D sound simulation can improve the capabilities of VR systems dramatically. Unfortunately, realistic 3D sound simulations are expensive and demand a tremendous amount of computational power to calculate reverberation, occlusion, and obstruction effects. To use 3D sound in a PC-based training system as a way to direct and guide trainees to observe specific events in 3D space, a cheaper alternative has to be provided, so that a broader range of applications can take advantage of this modality. To address this issue, we focus in this paper on the evaluation of a low-cost 3D sound simulation that is capable of providing traceable 3D sound events. We describe our experimental system setup using conventional stereo headsets in combination with a tracked HMD device and present our results with regard to precision, speed, and used signal types for localizing simulated sound events in a virtual training environment     

Using immersive virtual environments for certification

As virtual environments move from research laboratories to commercial use, there is a need to define the appropriate role of VEs in certifying the systems they simulate. This article describes the unique features of this developing technology, as well some key issues to consider when using VEs for certification     

A framework to design 3D interaction assistance in constraints-based virtual environments

The equilibrium of complex systems often depends on a set of constraints. Thus, credible virtual reality modeling of these systems must respect these constraints, in particular for 3D interactions. In this paper, we propose a generic framework for designing assistance to 3D user interaction in constraints-based virtual environment that associates constraints, interaction tasks and assistance tools, such as virtual fixtures (VFs). This framework is applied to design assistance tools for molecular biology analysis. Evaluation shows that VF designed using our framework improve effectiveness of the manipulation task.