Peltier Haptic Interface (PHI) for improved sensation of touch in virtual environments

In this report we describe an advanced virtual reality glove that we are developing, called the Peltier Haptic Interface (PHI), which will provide improved sensation of touch in virtual environments. PHI will provide force/pressure feedback that can be varied independently on each finger, as well as temperature sensation that can be varied non-uniformly over the whole hand. The combination of these sensations will provide a more realistic sense of touch and significantly increase the realism of virtual environments. PHI will find extensive applications in biomedical simulations, teaching, industrial line training, and many other areas.     

Virtual interpersonal touch: Haptic interaction and copresence in collaborative virtual environments

As digital communication becomes more commonplace and sensory rich, understanding the manner in which people interact with one another is crucial. In the current study, we examined the manners in which people touch digital representations of people, and compared those behaviors to the manner in which they touch digital representations of nonhuman objects. Results demonstrated that people used less force when touching people than other nonhuman objects, and that people touched the face with less force than the torso area. Finally, male digital representations were touched with more force than female representations by subjects of both genders. We discuss the implications of these data to the development of haptic communication systems as well as for a methodology of measuring the amount of copresence in virtual environments.

Haptic interpersonal communication: improvement of actions coordination in collaborative virtual environments

This article explores the use of haptic feedback for interpersonal communication in collaborative virtual environments. After a detailed presentation of all communication mechanisms involved, we propose the investigation of a low-level communication approach through the feedthrough mechanism. This channel is used to communicate kinematic information about a partner??s gestures during closely coupled collaboration. Several communication metaphors, with complementary behaviors, were investigated to improve the coordination between two partners during an assembly task. The results clearly show the role of communication strategies for the improvement of gesture coordination and highlight the correlation between applied force and the level of efficiency.     

Haptic discrimination of virtual surface slope

We report the difference thresholds of the slope of a virtual surface rendered via a force–feedback haptic interface with the body frontal plane as a reference. The factors varied in experiments were the stiffness of a virtual plane, the lateral velocity with which the haptic probe scanned the plane, the length of a scanning interval, the movement direction of the probe to the body frontal plane (toward or away from the body), and lateral scanning direction (left-to-right or right-to-left). Measured slope thresholds ranged from 8.33° to 12.74° and were generally higher than or similar to previously published thresholds for haptic orientation or angle discrimination. The results suggested that haptic slope discriminability was independent of surface stiffness and lateral scanning velocity. Slope discrimination was largely affected by the lateral scan distance, indicating that the terminal difference of probe normal position can be an important sensory cue. In terms of scan direction, inward or rightward scans resulted in better slope discrimination than outward or leftward scans, respectively. These thresholds and findings have implications for haptics applications that involve geometric model modification or simplification of virtual objects while preserving their perceptual properties.     

Intelligent virtual environments for virtual reality art

The development of virtual reality (VR) art installations is faced with considerable difficulties, especially when one wishes to explore complex notions related to user interaction. We describe the development of a VR platform, which supports the development of such installations, from an art+science perspective. The system is based on a CAVE™-like immersive display using a game engine to support visualisation and interaction, which has been adapted for stereoscopic visualisation and real-time tracking. In addition, some architectural elements of game engines, such as their reliance on event-based systems have been used to support the principled definition of alternative laws of Physics. We illustrate this research through the development of a fully implemented artistic brief that explores the notion of causality in a virtual environment. After describing the hardware architecture supporting immersive visualisation we show how causality can be redefined using artificial intelligence technologies inspired from action representation in planning and how this symbolic definition of behaviour can support new forms of user experience in VR.     

A study of locomotion paradigms for immersive medical simulation environments

Immersive virtual environments are increasingly used for medical training and rehearsal. Immersive environments can provide realistic context for team training, where success relies on practiced coordination between individual members. Using immersive virtual environments, medical teams can practice in situations that would otherwise be difficult or expensive to create. It has been shown that individuals perform poorly when the training environment differs significantly from practice 2005. Efforts have been made to close this gap using virtual environments. Interacting in a virtual space requires a robust locomotion paradigm. Locomotion paradigms are methods that allow an individual to move and navigate through virtual environments. Locomotion paradigms should be intuitive to the user, and not distract from the central task of medical training. In this paper, we describe and evaluate four locomotion paradigms, Look & Go, Push & Go, Point & Go, and Grab & Drag, using objective metrics to evaluate navigational efficiency. This study was performed with 98 volunteers predominantly of clinical backgrounds. With the comparison between the performances of game-playing and non-game-playing subjects, we have shown that game-playing experiences do not significantly affect the locomotion performances with the four proposed paradigms. The results of this study suggests the Grab & Drag as the best method among four locomotion paradigms in triage/trauma scenarios, where trainees need to find and help patients scattered in a large area.     

Realization of reconfigurable virtual environments for virtual testing

1 Introduction The scalability of virtual environments (VEs) that allow users to change and modify their contents and context depending on application requirements has been a de facto feature of virtual reality technology. Engineering uses such as virtual testing and exper- imenting applications demand VEs to be highly or fully reconfigurable. In reality, however, satisfactory reconfiguration of a virtual environment is yet to be achieved, due to the high accuracy of spatial data in- put and…     

虚拟环境的用户意图捕获

目的虚拟制造环境中需要复杂精确的3D人机交互。目前的虚拟环境(VE)的主要问题是人在交互过程中的认知和操作负荷太重,交互效率亟需提高。解决此问题的重要途径是提高机器的认知能力。方法本文研究了用户意图的分析和抽取,并建立多通道用户意图理解的算法,以此来提高交互效率。结果结合虚拟装配应用给出了典型意图的实验结果并给予分析。通过实验对多通道意图的可用性和可靠性,以及基于意图系统的实时性进行了评估。实验是虚拟装配空间中用户拾取对象意图的实验。当3维鼠标和对象距离为5 000 mm时,传统系统中操作平均耗时5.344 7 s,而基于意图的系统中平均耗时2.326 6 s。基于意图的系统极大地降低了操作的时间和复杂度。结论采用意图驱动的系统情景转换能在虚拟环境工作中有效地降低人的认知负荷,并能很好地帮助系统开发者进行混成系统的建模和分析,降低开发的复杂度。实践结果表明用户意图理解的多通道模型和算法能极大地提高交互式系统的交互自然性和交互效率。该方法不仅适用于本文所用的虚拟装配系统,对于所有的虚拟环境应用场景都有同样的有效性。     

Video mosaics for virtual environments

As computer-based video becomes ubiquitous with the expansion of transmission, storage, and manipulation capabilities, it will offer a rich source of imagery for computer graphics applications. This article looks at one way to use video as a new source of high-resolution, photorealistic imagery for these applications. If you walked through an environment, such as a building interior, and filmed a video sequence of what you saw you could subsequently register and composite the video images together into large mosaics of the scene. In this way, you can achieve an essentially unlimited resolution. Furthermore, since you can acquire the images using any optical technology, you can reconstruct any scene regardless of its range or scale. Video mosaics can be used in many different applications, including the creation of virtual reality environments, computer-game settings, and movie special effects. I present algorithms that align images and composite scenes of increasing complexity-beginning with simple planar scenes and progressing to panoramic scenes and, finally, to scenes with depth variation. I begin with a review of basic imaging equations and conclude with some novel applications of the virtual environments created using the algorithms presented     

Construction of virtual patient model for maxillofacial palpation training system

Palpation has been considered as one of the important diagnostic skills for doctors, which is conducted on a patient to identify the size, the consistency, and the location of a subcutaneous tumor. Accurate palpation skill often detects the cause of disease early. Even in the field of dentistry, palpation has been considered as the important diagnostic skill for dentists. By the way, any practical training of palpation against a patient did not implemented in the dental education because the patient safety has a priority more than its educational effect. Then we propose a training system for maxillofacial palpation by using virtual reality and haptic interface. The details of modeling a virtual patient model for the training system are shown in this paper, and the experimental results are also described.     

Multiuser 3D virtual simulation environments support in the Gnutella peer-to-peer network

One of the challenges for 3D multiuser virtual simulation environments (3DMUVEs) developers is to keep the shared virtual simulation environment synchronized among all the participating users’ terminals. Support to 3DMUVEs through traditional client–server communication model offers simpler management but can lead to bottlenecks and higher latencies. Peer-to-peer communication model, on the other hand, offers no central coordination but are more complex to manage. Current peer-to-peer networks, such as KaZaA and Gnutella, provide multimedia sharing services but do not support multiuser 3D virtual environment (VE) applications.This paper describes a solution to support 3DMUVEs in a hybrid peer-to-peer Gnutella network, which provides session control and distributed shared VE synchronization. As a result of this work, two components specified by the ongoing multiuser extension to the MPEG-4 standard were implemented and integrated to the Gnutella network for control and synchronization. This solution minimizes the disadvantages of client–server and pure peer-to-peer models. The results show that this approach can be a feasible solution, specially for spontaneous 3DMUVEs that can emerge from any user, with no investment needed (apart from his own computer). The use of peer-to-peer networks such as the Gnutella could be used as a test environment for companies wishing to check both their multiuser 3DMUVEs software for correctness and their acceptance by the users community before making heavy investments.     

Haptic collision handling for simulation of transnasal surgery

Simulation of endoscopic navigation in the narrow nasal cavity poses important challenges to the computation of adequate and near‐realistic collision response and haptic feedback because extensive multidirectional contact and massive tissue deformations are inevitable. We present a virtual coupling algorithm that provides stable collision response as well as intuitive and smooth haptic interaction in all phases of the simulation. In each iteration, continuous collision detection between the point shell representing the surface of the virtual patient anatomy and the endoscope, represented by a cylinder, is performed. This allows for rolling back the instrument movement to the point in time the first collision occurred. Subsequently, a relaxation process locally optimizes the position and orientation of the instrument. A novel method of applying contact forces to colliding tissues and thus triggering appropriate deformations improves the fluency of navigation. This paper describes the algorithm and presents experimental results. © Her Majesty the Queen in Right of Canada 2012. Reproduced with the permission of the Minister of Medical Devices, National Research Council Canada.     

Volumetric virtual environments

Driven by fast development of both virtual reality and volume visualization,we discuss some critical techniques towards building a volumetric VR system,specifically the modeling,rendering,and manipulations of a volumetric scene.Techniques such as voxel-based object simplification,accelerated volume rendering,fast stereo volume rendering,and volumetric “collision detection“ are introduced and improved,with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.     

Visual gesture interfaces for virtual environments

Virtual environments provide a whole new way of viewing and manipulating 3D data. Current technology moves the images out of desktop monitors and into the space immediately surrounding the user. Users can literally put their hands on the virtual objects. Unfortunately, techniques for interacting with such environments are yet to mature. Gloves and sensor-based trackers are unwieldy, constraining and uncomfortable to use. A natural, more intuitive method of interaction would be to allow the user to grasp objects with their hands and manipulate them as if they were real objects.We are investigating the use of computer vision in implementing a natural interface based on hand gestures. A framework for a gesture recognition system is introduced along with results of experiments in colour segmentation, feature extraction and template matching for finger and hand tracking, and simple hand pose recognition. Implementation of a gesture interface for navigation and object manipulation in virtual environments is presented.     

Execution infrastructure for normative virtual environments

Virtual Institutions (VIs) have proven to be adequate to engineer applications where participants can be humans and software agents. VIs combine Electronic Institutions (EIs) and 3D Virtual Worlds (VWs). In this context, Electronic Institutions are used to establish the regulations that structure interactions and support software agent participation while Virtual Worlds facilitate human participation. In this paper we propose Virtual Institution eXEcution Environment (VIXEE) as an innovative communication infrastructure for VIs. Using VIXEE to connect Virtual Worlds and EI opens EI to humans, providing a fully operational and comprehensive environment. The main features of the infrastructure are (i) the causal connection between Virtual Worlds and Electronic Institutions, (ii) the automatic generation and update of the VIs' 3D visualization and (iii) the simultaneous participation of users from different virtual world platforms. We illustrate the execution of VIXEE system in a simple eAuction house example and use this example to evaluate the performance of our solution.     

Magic Lenses for augmented virtual environments

The authors developed a Magic Lens framework for Scape, an augmented virtual environment (AVE). They generalize the functional characteristics of Magic Lenses in terms of 3D visualization in AVEs and present two tangible Magic Lens-enabled devices with complementary interface capabilities. The authors also demonstrate their Magic Lens devices through testbed applications relevant to urban planning and medical training. This article explores an interface technique that manages viewing complexity and offers a set of versatile visualization capabilities in 3D augmented virtual environments (AVE).     

Rapid prototyping for distributed virtual environments

The authors combine rapid and exploratory prototyping techniques to capture initially unknown, interdependent requirements in the development of distributed virtual environment applications. They employ containerization to accelerate data exchange     

Topology simplification for polygonal virtual environments

We present a topology simplifying approach that can be used for genus reductions, removal of protuberances, and repair of cracks in polygonal models in a unified framework. Our work is complementary to the existing work on geometry simplification of polygonal datasets and we demonstrate that using topology and geometry simplifications together yields superior multiresolution hierarchies than is possible by using either of them alone. Our approach can also address the important issue of repair of cracks in polygonal models, as well as for rapid identification and removal of protuberances based on internal accessibility in polygonal models. Our approach is based on identifying holes and cracks by extending the concept of α-shapes to polygonal meshes under the L_∞ distance metric. We then generate valid triangulations to fill them using the intuitive notion of sweeping an L_∞ cube over the identified regions