The AHI

Haptic interaction in slow virtual environments (VEs) can become unstable due to the phase lag introduced in the control loop by the slow update rate of the VE. Increasing the physical damping and/or limiting the contact stiffness rendered to users can mitigate the destabilizing effect of the low VE update rate. However, large physical damping and compliant virtual contacts decrease the sense of presence in VEs, especially during interaction with rigid virtual objects. To increase the maximum virtual contact stiffness that can be rendered to users without increasing the interface damping, this paper proposes a control strategy based on multirate wave communications between a haptic interface and a VE updated at a slow and fixed rate. The multirate wave communications are shown to be guaranteed passive only if the decrease of the wave sampling rate at the connection between the haptic interface and the VE does not cause aliasing. Therefore, an antialiasing low-pass filter is placed before the wave rate drop in the communications. The passivity condition is verified analytically and numerically for multirate haptic interaction in VEs with various contact stiffnesses and update rates. The transparency of haptic interaction in slow VEs to which users connect via passive multirate wave communications is investigated analytically in the frequency domain. Experiments validate that passive multirate wave communications can render stiffer contact in slow VEs than conventional direct coupling, and illustrate the destabilizing effect of the aliasing caused by the sampling rate drop in the communications.

The complex nature of virtual environments customarily hinders users to interact in a natural, intuitive and optimal way. Different user characteristics are hardly taken into account when designing 3D user interfaces for virtual environments. We envision that user interaction in virtual environments can be enhanced by integrating adaptation and personalization into 3D user interfaces. Through our research, we aim to provide adaptive and personalized 3D user interfaces for enhancing user interaction in virtual environments. The establishment of a user model becomes an important first step to facilitate adaptation and personalization to the user. In order to partly construct the user model, we carried out an experiment on 3D target acquisition task with four user groups (differing in experience level and gender). In this paper, we present a general user model that will enable first-time users to benefit instantly from adaptation and personalization in virtual environments.Keywordsvirtual environmentsadaptive 3D interfacesuser model

This paper reports the effectiveness of a tactile stimulus in a virtual environment to increase people's motivations during a monotonous task by comparing a touch with only visual stimuli and another with both visual and tactile stimuli. Although touch interaction with robots showed various positive effects such as improved motivation, visual and haptic stimuli were not separated due to the form of the touch in physical environments. Virtual environments enable us to investigate such effects by separating the modality of touch: a visual-only-touch and a visual-tactile touch. We experimented in a virtual environment where participants did a monotonous task after experiencing either a visual-only-touch or a visual-tactile-touch by an agent to compare them in the context of motivation improvements and the perceived impressions. The experimental results showed that a visual-tactile touch significantly increases the motivations of the participants for monotonous tasks. On the other hand, their likability of the agents is not significantly changed by the touch modalities.

Interactive Virtual Environments (VEs) have the potential to increase student interest in soil science. Accordingly a bespoke ‘soil atlas’ was created using Java3D as an interactive 3D VE, to show soil information in the context of (and as affected by) the over-lying landscape. To display the below-ground soil characteristics, four sets of artistic illustrations were produced, each set showing the effects of soil organic-matter density and water content on fungal density, to determine potential for visualisations and interactivity in stimulating interest in soil and soil illustrations, interest being an important factor in facilitating learning. The illustrations were created using 3D modelling packages, and a wide range of styles were produced. This allowed a preliminary study of the relative merits of different artistic styles, scientific-credibility, scale, abstraction and ‘realism’ (e.g. photo-realism or realism of forms), and any relationship between these and the level of interest indicated by the study participants in the soil visualisations and VE. The study found significant differences in mean interest ratings for different soil illustration styles, as well as in the perception of scientific-credibility of these styles, albeit for both measures there was considerable difference of attitude between participants about particular styles. There was also found to be a highly significant positive correlation between participants rating styles highly for interest and highly for scientific-credibility. There was furthermore a particularly high interest rating among participants for seeing temporal soil processes illustrated/animated, suggesting this as a particularly promising method for further stimulating interest in soil illustrations and soil itself.

The challenges of measuring, managing, and predicting negative side effects (i.e. cybersickness) during virtual environment (VE) interaction and unwanted aftereffects continue to persist. Most assessments have been limited to subjective questionnaires. This study investigated the effects of VE interaction on nausea (gastric activity) and the development of a quantitative model affording cybersickness prediction. This cybersickness state estimation model (CSEM) offers a quantitative (i.e. physiological based) predictability to cybersickness. The model relates time, recordable gastric activity using electrogastrogram (EGG) measures as a physiological predictor and subjective sickness estimates. This work employs neural network algorithms to model user state associated with cybersickness. Neural network models were designed, trained, and tested to determine the network trainability and accuracy. Mean SSQ total severity scores indicate significant differences between conditions. All CSEM models had a low sum of squared error. The models were found to be accurate in predicting cybersickness from unseen data.

Efforts exist to combine a brain-machine interface (BMI) into a 3D virtual environment (VE) for visual tasks. User interaction via haptic stimuli within the VE is still unexplored for developing the BMI however, due to little understanding of cognitive processes related to such haptic interaction. Hence, we investigated a feasibility of estimating cognitive processes related to haptic interaction. Involved in the investigation, human participants undertook a task via different haptic stimuli (e.g., force and vibration) within a 3D VE. Their brain activities evoked by the stimuli were acquired as electroencephalography signals. Patterns of event-related potential and power spectral density were extracted from the signals, indicating activation in certain brain areas. The estimation of connectivity among these areas used directed transfer function, emphasizing on the middle of the $\beta$ band (14 30)

The usability of virtual reality (VR) controller interfaces are often complex and difficult for first time users. Most controllers provide minimal feedback which relegates the potential for heightened interaction and feedback within virtual experiences. This research explores how haptic technology systems partnered with VR can deliver immersive interactions between user and virtual environment (VE). This research involves the development of a haptic glove interface prototype that incorporates a force feedback and vibrotactile feedback system. It focuses on determining a workflow that communicates in real-time user interaction and environmental feedback using Unreal Engine and the produced haptic glove system. Testing and calibrating the prototype feedback system provided a baseline for developers to rationalise and improve accuracy of current real-time virtual feedback systems. The evaluation of this research in industry unfolds new technical knowledge for implementing a wider range of haptic technologies within VR. This further development would involve reviewing the usability and interaction standards for VR users in the design process.

Virtual environment research has focused on interactive image generation and has largely ignored acoustic modeling for spatialization of sound. Yet, realistic auditory cues can complement and enhance visual cues to aid navigation, comprehension, and sense of presence in virtual environments. A primary challenge in acoustic modeling is computation of reverberation paths from sound sources fast enough for real-time auralization. We have developed a system that uses precomputed spatial subdivision and “beam tree” data structures to enable real-time acoustic modeling and auralization in interactive virtual environments. The spatial subdivision is a partition of 3D space into convex polyhedral regions (cells) represented as a cell adjacency graph. A beam tracing algorithm recursively traces pyramidal beams through the spatial subdivision to construct a beam tree data structure representing the regions of space reachable by each potential sequence of transmission and specular reflection events at cell boundaries. From these precomputed data structures, we can generate high-order specular reflection and transmission paths at interactive rates to spatialize fixed sound sources in real-time as the user moves through a virtual environment. Unlike previous acoustic modeling work, our beam tracing method: 1) supports evaluation of reverberation paths at interactive rates, 2) scales to compute highorder reflections and large environments, and 3) extends naturally to compute paths of diffraction and diffuse reflection efficiently. We are using this system to develop interactive applications in which a user experiences a virtual environment immersively via simultaneous auralization and visualization.

Presentation of more haptic information to improve the users interactive capability is an important and challenging task in the virtual environment. As an emerging haptic feedback technology, electrovibration is an underlying solution to enhance the systems interactivity and improve user experience. However, such a solution is rarely studied in a virtual environment. In this work, we explore a new VR interaction method based on electrovibration technology with a touch screen and conduct evaluations about it. The key idea is to incorporate a set of manipulation gestures and three types of electrovibration in the VR interaction to help users acquire different kinds of tactile perception in the virtual manipulation. We present the evaluation in which we compare user performance measured first in a Fitts law task to evaluate different electrovibration types and then in a virtual office application to assess the interactive user interface. Our results show that the precision of interactions is significantly improved with the electrovibration haptic feedback. To the best of our knowledge, this is the first work to introduce electrovibration haptic feedback into the VR human-computer interaction and our work enlightens the potential of the electrovibration touchscreen-based interaction in virtual environments.

Virtual Reality (VR) has been showing potential in new and diverse areas, notably in education. However, there is a lack of studies in the Foreign Language Teaching and Learning field, particularly in listening comprehension. Therefore, this study investigated the effects of avatar animations and lip synchronization, and user interaction; features deemed relevant in this broader area. A sociodemographic, a quick CEFR - Common European Framework of Reference for Languages - 15-minute English test, and questionnaire were used to evaluate the participants' Presence, Quality of Experience, Cybersickness and Knowledge Retention. Results show that, overall, the use of avatars with realistic animations and movements, and featuring lip synchronization have a positive influence on the users' sense of presence, knowledge retention and a more enjoyable overall quality of experience. The same can be said for the use of object interaction and navigation in the cultural representative environment, which had an overall positive impact.

Security and stability are important for interactive behavior of virtual object in the virtual environment. To achieving a effective method for region limit to all virtual models is the key to secure and stable virtual environment. The paper analyzed the principle and approach of limit to model behavior region, presented a method based on VRML with validations. The method is effective for safe, stable human-computer interaction in virtual environment, and served for VR-based products design, process approach, and accurate evaluation.

In recent years, there has been a growing interest in developing force feedback interfaces that allow people to access information presented in 3D virtual reality environments (VEs). One of the major application fields is medicine. Several cases exist where standard medical treatment cannot be applied to patients for several reasons, such as distance from hospital, lack of specialized doctor, and lack of medical equipment. The use of haptic‐enabled virtual environments provides an alternative solution in a variety of such cases, thus enabling assessment and treatment of patients. Furthermore, haptic‐enabled virtual environments provide a nonhazardous means of treatment for several disorders like phobia treatment, where the patient has to be exposed to the phobia object. Training of disabled people, like the visually impaired, is another important application of haptic‐enabled VEs. This chapter presents an extended description of haptic virtual environments and the major methodologies and techniques used in medical applications. Further, it demonstrates indicatively a number of applications in order to illustrate the applicability of VEs in several areas of medical treatment and training.

BackgroundVirtual reality (VR) offers unprecedented opportunity as a scientific tool to study visuomotor interactions, training, and rehabilitation applications. However, it remains unclear if haptic-free hand-object interactions in a virtual environment (VE) may differ from those performed in the physical environment (PE). We therefore sought to establish if the coordination structure between the transport and grasp components remain similar whether a reach-to-grasp movement is performed in PE and VE.MethodReach-to-grasp kinematics were examined in 13 healthy right-handed young adults. Subjects were instructed to reach-to-grasp-to-lift three differently sized rectangular objects located at three different distances from the starting position. Object size and location were matched between the two environments. Contact with the virtual objects was based on a custom collision detection algorithm. Differences between the environments were evaluated by comparing movement kinematics of the transport and grasp components.ResultsCorrelation coefficients, and the slope of the regression lines, between the reach and grasp components were similar for the two environments. Likewise, the kinematic profiles of the transport velocity and grasp aperture were strongly correlated across the two environments. A rmANOVA further identified some similarities and differences in the movement kinematics between the two environments - most prominently that the closure phase of reach-to-grasp movement was prolonged when movements were performed in VE.ConclusionsReach-to-grasp movement patterns performed in a VE showed both similarities and specific differences compared to those performed in PE. Additionally, we demonstrate a novel approach for parsing the reach-to-grasp movement into three phases- initiation, shaping, closure- based on established kinematic variables, and demonstrate that the differences in performance between the environments are attributed to the closure phase. We discuss this in the context of how collision detection parameters may modify hand-object interactions in VE. Our study shows that haptic-free VE may be a useful platform to study reach-to-grasp movements, with potential implications for haptic-free VR in neurorehabilitation.

In this paper, we propose an approach to real-time haptic interaction based on the concept of simulating the constraining propertes of space. Research on haptic interaction has been conducted from the points of view of both surface and volume rendering. Most approaches to surface rendering—such as the constraint-based god-object method, the point-based approach, and the virtual proxy approach—have dealt only with the interaction with an object surface. Whereas, in volume rendering approaches, algorithms for representing volume data through interactions in space have been investigated. Our approach provides a framework for the representation of haptic interaction with both surface and space. We discretize the space using a tetrahedral cell mesh and associate a constraining property with each cell. The interaction of the haptic interface points with a volume is simulated using the constraining properties of the cells occupied by this volume. We implemented a fast computation algorithm that works at a haptic rate. The algorithm is robust in that any sudden or quick motion of the user does not disturb the computation, and the computation time for each cycle is independent of the complexity of the model as a whole. To demonstrate the performance of the proposed method, we present experimental results on the interaction with models of varying complexity. Also, we discuss some problems that need to be solved in future work.

Hand gestures facilitate user interaction and immersion in virtual museum applications. These gestures allow users to navigate virtual exhibitions, interact with virtual artifacts, and control virtual environments naturally and intuitively. This study introduces a deep learning-driven approach for hand gesture recognition using wearable vision sensors designed for interactive virtual museum environments. The proposed approach employs an image-based feature extraction strategy that focuses on capturing five partial occupancy areas of the hand. Notably, a deep learning strategy using the bidirectional long short-term memory (Bi-LSTM) model is adopted to construct an effective model for hand gesture identification. The bidirectionality of Bi-LSTM enables it to capture dependencies in both forward and backward directions, providing a more comprehensive understanding of temporal relationships in the data. The bidirectional nature allows the model to better capture the dynamics and complexities of hand motions, leading to improved accuracy and robustness. The performance evaluation includes experiments on publicly available datasets, considering virtual and real museum scenarios. The results highlight the Bi-LSTM-based approach’s superiority by accurately distinguishing various hand gestures. The experimental findings demonstrate that combining the five area ratios and Bi-LSTM classification enables robust recognition of diverse hand gestures and effectively discriminates between similar actions, such as slide left and right classes. Additionally, it shows promising detection performance compared to conventional machine learning models and state-of-the-art (SOTA) methods. The presented approach is promising for enhancing user interaction and immersion in virtual museum experiences.