ICAT-EGVE2015

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https://diglib.eg.org/handle/10.2312/13833

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How to Time Travel in Highly Immersive Virtual Reality
(The Eurographics Association, 2015) Pizarro, Rodrigo; Berkers, Keren-Or; Slater, Mel; Friedman, Doron; Masataka Imura and Pablo Figueroa and Betty Mohler
What would it be like to be able to time travel to the past, meet your previous self, and override your previous actions in order to achieve a better outcome? While we cannot (yet?) achieve physical time travel, digital technologies now allow us to experience virtual time travel. We have developed a method for implementing time travel in highly immersive virtual reality (VR) and here we describe the underlying technology in the context of a scenario that involves a shooting event in a virtual gallery. Our method includes two layers of abstraction: i) a narrative layer that represents scenarios as a set of events and state transitions, and uses preconditions to enforce consistency, and ii) a VR layer that includes low level controllers for low level synchronization and animation. The narrative layer is designed to ensure that following time travel the events would unfold exactly as they did in the previous time around, except for the specific changes resulting from the actions of the time traveling participant. The VR layer controls the fine details, including recording and replaying motion capture data and audio, which allows the participants to experience their own previous selves as animated avatars. The system was used for a psychological experiment, and in this paper we focus on the technical method and on the lessons learned from implementing VR time travel.
Ring-shaped Haptic Device with Vibrotactile Feedback Patterns to Support Natural Spatial Interaction
(The Eurographics Association, 2015) Ariza Núñez, Oscar Javier; Lubos, Paul; Steinicke, Frank; Bruder, Gerd; Masataka Imura and Pablo Figueroa and Betty Mohler
Haptic feedback devices can be used to improve usability, performance and cognition in immersive virtual environments (IVEs) and have the potential to significantly improve the user's virtual reality (VR) experience during natural interaction. However, there are only few affordable and reliable haptic devices that have a light-weight, unencumbering, simple and versatile form factor which does not prevent natural interaction with other objects or devices at the same time. In this paper we present such a ring-shaped wireless haptic feedback device, and we describe different vibrotactile signal patterns which can be used to provide proximity-based cues during 3D interaction with virtual objects. We present a usability study in which we evaluated the device and feedback patterns.
Visually Induced Motion Sickness Estimation and Prediction in Virtual Reality using Frequency Components Analysis of Postural Sway Signal
(The Eurographics Association, 2015) Chardonnet, Jean-Rémy; Mirzaei, Mohammad Ali; Mérienne, Frédéric; Masataka Imura and Pablo Figueroa and Betty Mohler
The paper proposes a method for estimating and predicting visually induced motion sickness (VIMS) occurring in a navigation task in a 3D immersive virtual environment, by extracting features from the body postural sway signals in both the time and frequency domains. Past research showed that the change in the body postural sway may be an element for characterizing VIMS. Therefore, we conducted experiments in a 3D virtual environment where the task was simply a translational movement with different navigation speeds. By measuring the evolution of the body's center of gravity (COG), the analysis of the sway signals in the time domain showed a dilation of the COG's area, as well as a change in the shape of the area. Frequency Components Analysis (FCA) of the sway signal gave an efficient feature to estimate and predict the level of VIMS. The results provide promising insight to better monitor sickness in a virtual reality application.
Hybrid Eye Tracking: Combining Iris Contour and Corneal Imaging
(The Eurographics Association, 2015) Plopski, Alexander; Nitschke, Christian; Kiyokawa, Kiyoshi; Schmalstieg, Dieter; Takemura, Haruo; Masataka Imura and Pablo Figueroa and Betty Mohler
Passive eye-pose estimation methods that recover the eye-pose from natural images generally suffer from low accuracy, the result of a static eye model, and the recovery of the eye model from the estimated iris contour. Active eye-pose estimation methods use precisely calibrated light sources to estimate a user specific eye-model. These methods recover an accurate eye-pose at the cost of complex setups and additional hardware. A common application of eye-pose estimation is the recovery of the point-of-gaze (PoG) given a 3D model of the scene. We propose a novel method that exploits this 3D model to recover the eye-pose and the corresponding PoG from natural images. Our hybrid approach combines active and passive eye-pose estimation methods to recover an accurate eye-pose from natural images. We track the corneal reflection of the scene to estimate an accurate position of the eye and then determine its orientation. The positional constraint allows us to estimate user specific eye-model parameters and improve the orientation estimation. We compare our method with standard iris-contour tracking and show that our method is more robust and accurate than eye-pose estimation from the detected iris with a static iris size. Accurate passive eye-pose and PoG estimation allows users to naturally interact with the scene, e.g., augmented reality content, without the use of infra-red light sources.
Development of Mutual Telexistence System using Virtual Projection of Operator's Egocentric Body Images
(The Eurographics Association, 2015) Saraiji, MHD Yamen; Fernando, Charith Lasantha; Minamizawa, Kouta; Tachi, Susumu; Masataka Imura and Pablo Figueroa and Betty Mohler
In this paper, a mobile telexistence system that provides mutual embodiment of user's body in a remote place is discussed. A fully mobile slave robot was designed and developed to deliver visual and motion mapping with user's head and body. The user can access the robot remotely using a Head Mounted Display (HMD) and set of head trackers. This system addresses three main points that are as follows: User's body representation in a remote physical environment, preserving body ownership toward the user during teleoperation, and presenting user's body interactions and visuals into the remote side. These previous three points were addressed using virtual projection of user's body into the egocentric local view, and projecting body visuals remotely. This system is intended to be used for teleconferencing and remote social activities when no physical manipulation is required.
Analysis of Depth Perception with Virtual Mask in Stereoscopic AR
(The Eurographics Association, 2015) Otsuki, Mai; Kuzuoka, Hideaki; Milgram, Paul; Masataka Imura and Pablo Figueroa and Betty Mohler
A practical application of Augmented Reality (AR) is see-through vision, a technique that enables a user to observe an inner object located behind a real object by superimposing the virtually visualized inner object onto the real object surface (for example, pipes and cables behind a wall or under a floor). A challenge in such applications is to provide proper depth perception when an inner virtual object image is overlaid on a real object. To improve depth perception in stereoscopic AR, we propose a method that overlays a random-dot mask on the real object surface. This method conveys to the observers the illusion of observing the virtual object through many small holes. We named this perception ''stereoscopic pseudo-transparency.'' Our experiments investigated (1) the effectiveness of the proposed method in improving the depth perception between the real object surface and the virtual object compared to existing methods, and (2) whether the proposed method can be used in an actual AR environment.
Effectiveness of Spatial Coherent Remote Drive Experience with a Telexistence Backhoe for Construction Sites
(The Eurographics Association, 2015) Fernando, Charith Lasantha; Saraiji, MHD Yamen; Seishu, Yoshio; Kuriu, Nobuo; Minamizawa, Kouta; Tachi, Susumu; Masataka Imura and Pablo Figueroa and Betty Mohler
In this paper, a spatial coherent remote driving system was designed and implemented to operate a telexistence backhoe over a wireless network. Accordingly, we developed a 6 degrees of Freedom (DOF) slave robot that can mimic the human upper body movement; a cockpit with motion tracking system and a Head Mounted Display (HMD) where the operator was provided with a HD720p ultra low latency video and audio feedback from the remote backhoe, and a controller to manipulate the remote backhoe. Spatial coherent driving could help manipu- lating heavy machinery without any prior training and perform operations as if they were operating the machinery locally. Moreover, construction work could be performed uninterrupted (24/7) by operators remotely log-in from all over the world. This paper describes the design requirements of developing the telexistence backhoe followed by several field experiments carried out to verify the effectiveness of spatial coherent remote driving experience in construction sites.
An Evaluation of the Effects of Hyper-Natural Components of Interaction Fidelity on Locomotion Performance in Virtual Reality
(The Eurographics Association, 2015) Nabiyouni, Mahdi; Bowman, Doug A.; Masataka Imura and Pablo Figueroa and Betty Mohler
Virtual reality (VR) locomotion techniques that approximate real-world walking often have lower performance than fully natural real walking due to moderate interaction fidelity. Other techniques with moderate fidelity, however, are intentionally designed to enhance users' abilities beyond what is possible in the real world. We compared such hyper-natural techniques to their natural counterparts on a wide range of locomotion tasks for a variety of measures. The evaluation also considered two independent components of interaction fidelity: bio-mechanics and transfer function. The results show that hyper-natural transfer functions can improve locomotion speed and some aspects of user satis-faction, although this can come at the expense of accuracy for complicated path-following tasks. On the other hand, hyper-natural techniques designed to provide biomechanical assistance had lower performance and user acceptance than those based on natural walking movements. These results contribute to a deeper understanding of the effects of interaction fidelity and designer intent for VR interaction techniques.
Global Landmarks Do Not Necessarily Improve Spatial Performance in Addition to Bodily Self-Movement Cues when Learning a Large-Scale Virtual Environment
(The Eurographics Association, 2015) Meilinger, Tobias; Schulte-Pelkum, Jörg; Frankenstein, Julia; Berger, Daniel; Bülthoff, Heinrich H.; Masataka Imura and Pablo Figueroa and Betty Mohler
Comparing spatial performance in different virtual reality setups can indicate which cues are relevant for a realistic virtual experience. Bodily self-movement cues and global orientation information were shown to increase spatial performance compared with local visual cues only. We tested the combined impact of bodily and global orientation cues by having participants learn a virtual multi corridor environment either by only walking through it, with additional distant landmarks providing heading information, or with a surrounding hall relative to which participants could determine their orientation and location. Subsequent measures on spatial memory only revealed small and non-reliable differences between the learning conditions. We conclude that additional global landmark information does not necessarily improve user's orientation within a virtual environment when bodily-self-movement cues are available.
Development of Encountered-type Haptic Interface that can Independently Control Volume and Rigidity of 3D Virtual Object
(The Eurographics Association, 2015) Takizawa, Naoki; Yano, Hiroaki; Iwata, Hiroo; Oshiro, Yukio; Ohkohchi, Nobuhiro; Masataka Imura and Pablo Figueroa and Betty Mohler
This paper describes the development of an encountered-type haptic interface that can independently present the physical characteristics of 3D virtual objects, such as shape and rigidity, in the real world. This interface consists of nonexpandable balloons, syringe pumps, pressure sensors, linear actuators, and a PC. To change the rigidity of the balloon, the volume of air in the balloon is controlled by using a linear actuator and a pressure sensor based on Hooke's law. Furthermore, to change the volume of the balloon, the exposed surface area of the balloon is controlled by using another linear actuator with a trumpet-shaped tube. Performance tests of the system were conducted, and the effectiveness of the proposed interface was verified.
Roles in Collaborative Virtual Environments for Training
(The Eurographics Association, 2015) Claude, Guillaume; Gouranton, Valérie; Arnaldi, Bruno; Masataka Imura and Pablo Figueroa and Betty Mohler
In this paper we present a novel approach to role modelling for Collaborative Virtual Environments with an Action Oriented Scenario Engine. Our role model is able to take into account different data about the actions such as the abilities, rights or resources required by an actor to determine whether he or she can execute an action. Furthermore, it considers that any data about an actor can have an influence on his or her role in the simulation. We provide also a team organisation model to define the impacts of the rules of the team on the role of the actors as suggested by the role theory. To illustrate our work, we used our model in a Collaborative Virtual Environment for the Training of a neurosurgery procedure.
Anthropomorphism and Illusion of Virtual Body Ownership
(The Eurographics Association, 2015) Lugrin, Jean-Luc; Latt, Johanna; Latoschik, Marc Erich; Masataka Imura and Pablo Figueroa and Betty Mohler
In this paper we present a novel experiment to explore the impact of avatar realism on the illusion of virtual body ownership (IVBO) in immersive virtual environments, with full-body avatar embodiment and freedom of movement.We evaluated four distinct avatars presenting an increasing level of anthropomorphism in their detailed compositions. Our results revealed that each avatar elicited a relatively high level of illusion. However both machine-like and cartoon-like avatars elicited an equivalent IVBO, slightly superior to the human-ones. A realistic human appearance is therefore not a critical top-down factor of IVBO, and could lead to an Uncanny Valley effect.
Structural Color Display on Retro-reflective Objects
(The Eurographics Association, 2015) Amano, Toshiyuki; Minami, Kensuke; Masataka Imura and Pablo Figueroa and Betty Mohler
Structural color display is an illumination projection display technique that can generate a completely altered appearance. It has potential for the visualization of scientific simulation, material perception display, and other applications. This paper investigates how to alternate the directional illumination distribution to display a desired bidirectional reflectance distribution function (BRDF). For the display technique, we modeled the reflection property of retro-reflective coating and lightfield projection using a projector array. Because the overlap creates an illumination error with respect to the desired appearance when we simply project the desired appearance, we propose a projection image optimization method to ensure that we display the desired structural color. We performed an evaluation on the reflective rainbow of an optical disc, and its effectiveness was confirmed through simulation and hardware experiment.
X-Dimensional Display: Superimposing 2D Cross-Sectional Image inside 3D Wireframe Aerial Image
(The Eurographics Association, 2015) Furuyama, Yoshikazu; Makino, Yasutoshi; Shinoda, Hiroyuki; Masataka Imura and Pablo Figueroa and Betty Mohler
In this paper, we propose a new interactive volumetric display which simultaneously shows a floating 3D image and its 2D cross sectional image inside it. This display enables users to see an arbitrary cross sectional image by inserting a hand-held semi-transparent screen into the 3D image floating in the mid-air. This system has following possibilities: doctors easily see MRI images inside the 3D body image, and designers check the internal structure of a 3D object in CAD. We construct a prototype device to demonstrate our proposed method by combining a 3D display and an aerial imaging technology. The spinning LED array constructs the volumetric image, and which is optically mirrored to appear in the free-space by the transmissive mirror called Aerial Imaging Plate (AIP). We find that a fine meshed silk screen can be inserted into the aerial image without disturbing the shape of it. Cross sectional images can be projected onto it together with the 3D image. We demonstrate how a silk screen diffuses a 3D aerial image and a projected 2D image.
Frontmatter: Virtual Environments 2015
(The Eurographics Association, 2015) Imura, Masataka; Figueroa, Pablo; Mohler, Betty; Masataka Imura and Pablo Figueroa and Betty Mohler
Comparison and Evaluation of Viewpoint Quality Estimation Algorithms for Immersive Virtual Environments
(The Eurographics Association, 2015) Freitag, Sebastian; Weyers, Benjamin; Bönsch, Andrea; Kuhlen, Torsten W.; Masataka Imura and Pablo Figueroa and Betty Mohler
The knowledge of which places in a virtual environment are interesting or informative can be used to improve user interfaces and to create virtual tours. Viewpoint Quality Estimation algorithms approximate this information by calculating quality scores for viewpoints. However, even though several such algorithms exist and have also been used, e.g., in virtual tour generation, they have never been comparatively evaluated on virtual scenes. In this work, we introduce three new Viewpoint Quality Estimation algorithms, and compare them against each other and six existing metrics, by applying them to two different virtual scenes. Furthermore, we conducted a user study to obtain a quantitative evaluation of viewpoint quality. The results reveal strengths and limitations of the metrics on actual scenes, and provide recommendations on which algorithms to use for real applications.
Yther: A Proposal and Initial Prototype of a Virtual Reality Content Sharing System
(The Eurographics Association, 2015) Steed, Anthony; Masataka Imura and Pablo Figueroa and Betty Mohler
There are many virtual reality development tools, but we argue that none has solved the disparate problems of ease of content creation, openness of access for developers and broad support for a variety of immersive and nonimmersive virtual reality systems. Yther is a proposal and initial prototype of a platform for sharing immersive and non-immersive virtual environments. Yther doesn't propose a new content standard, but builds upon the Unity system. The first contribution of Yther is a clear separation of concerns between development of content (zones) and support for specific hardware. The second contribution is a set of abstractions that allow developer to author interaction techniques and behaviours without specific reference to the interaction devices that any particular runtime instance has. The third contribution is a mechanism within the Unity development environment for publishing content so that it can be made available for testing and sharing very easily. The current implementation of Yther is a prototype but it already demonstrates capabilities that distinguish it from similar systems.
Physical Space Requirements for Redirected Walking: How Size and Shape Affect Performance
(The Eurographics Association, 2015) Azmandian, Mahdi; Grechkin, Timofey; Bolas, Mark; Suma, Evan; Masataka Imura and Pablo Figueroa and Betty Mohler
Redirected walking provides a compelling solution to explore large virtual environments in a natural way. However, research literature provides few guidelines regarding trade-offs involved in selecting size and layout for physical tracked space. We designed a rigorously controlled benchmarking framework and conducted two simulated user experiments to systematically investigate how the total area and dimensions of the tracked space affect performance of steer-to-center and steer-to-orbit algorithms. The results indicate that minimum viable size of physical tracked space for these redirected walking algorithms is approximately 6m 6m with performance continuously improving in larger tracked spaces. At the same time, no ''optimal'' tracked space size can guarantee the absence of contacts with the boundary. We also found that square tracked spaces enabled best overall performance with steer-to-center algorithm also performing well in moderately elongated rectangular spaces. Finally, we demonstrate that introducing translation gains can provide a useful boost in performance, particularly when physical space is constrained. We conclude with the discussion of potential applications of our benchmarking toolkit to other problems related to performance of redirected walking platforms.
R-V Dynamics Illusion: Psychophysical Phenomenon Caused by the Difference between Dynamics of Real Object and Virtual Object
(The Eurographics Association, 2015) Kataoka, Yuta; Hashiguchi, Satoshi; Shibata, Fumihisa; Kimura, Asako; Masataka Imura and Pablo Figueroa and Betty Mohler
In Mixed-Reality (MR) space, it appeared that the sense of weight can be affected by a MR visual stimulation with a movable portion. We named this psychophysical influence caused by the difference between dynamics of the real object (R) and the virtual object (V) movement, the ''R-V Dynamics Illusion.'' There are many combinations of ex-periments that can be conducted. Previously, we conducted experiments of the case where the real object is rigid and the virtual object is dynamically changeable. In this paper, we conducted experiments of the case where the re-al object is liquid and both the real and the virtual objects are dynamically changeable. The results of the experi-ments showed that the subjects sensed weight differently when virtual object with a movable portion is superim-posed onto a real liquid object.
Influence of Path Complexity on Spatial Overlap Perception in Virtual Environments
(The Eurographics Association, 2015) Vasylevska, Khrystyna; Kaufmann, Hannes; Masataka Imura and Pablo Figueroa and Betty Mohler
Real walking in large virtual indoor environments within a limited real world workspace requires effective spatial compression methods. These methods should be unnoticed by the user. Scene manipulation that creates overlapping spaces has been suggested in recent work. However, there is little research focusing on users' perception of over-lapping spaces depending on the layout of the environment. In this paper we investigate how the complexity of the path influences the perception of the overlapping spaces it connects. We compare three spatial virtual layouts with paths that differ in complexity (length and number of turns). Our results suggest that an increase of the path's length is less efficient in decreasing overlap detection than a combination of length and additional turns. Furthermore, combination of paths that differ in complexity influences the distance perception within overlapping spaces.

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