Catálogo de publicaciones - libros

Hybrid display systems are those that combine different types of displays to exploit the complementary characteristics of the constituent display systems. In this paper, we introduce a hybrid system that combines a stereoscopic optical see-through head-mounted display (HMD) and a large projection display for an application in a multi-user ship painting training scenario. The proposed hybrid system’s projection display provides a large FOV and a physical metaphor to the ship surface with natural depth perception, while the HMD provides personal and unoccluded display of the motion training guides. To quantify its effectiveness, we conducted a human subject experiment, comparing the subject’s motion following task performance among three different display systems: large projection display, head-mounted display, and hybrid. The preliminary results obtained from the experiment has shown that given the same FOV, the hybrid system performed, despite problems with registration between the real and virtual worlds, up to par with the head-mounted display, and better than the projection display. Thus, it is expected that the hybrid display will result in higher task performance with the larger FOV factor available.

Subjects in the experiment reported observed the same spatial layout in the rectangular room and the cylindrical room from the exocentric ( 45° ) perspective first and then the egocentric ( 0° ) perspective. The mental representations of space were testified by the judgment of relative direction between objects. The results showed that subjects represented the spatial horizontal relation more accurately along the imagined direction that paralleled to the wall in the rectangular room but along the imagined direction that was ever faced in the cylindrical room. The rectangular room better facilitated the coding of spatial vertical information than the cylindrical room. Subjects could respond faster when retrieving the spatial relations in the direction faced during the observation. The data indicated that the orientation-specific representation was constructed and the environmental geometry could influence the accuracy of spatial direction in mind.

It is proposed that the concept of transparent telepresence can be closely approached through high fidelity technological mediation. It is argued that the matching of the system capabilities to those of the human user will yield a strong sense of immersion and presence at a remote site. Some applications of such a system are noted. The concept is explained and critical system elements are described together with an overview of some of the necessary system specifications.

This paper highlights some of the current problems in CVE development. These problems are mainly due to a lack of a good interaction model guiding the behaviour of the environments. This paper introduces the definition of a model based on the idea of the . The key concepts for understanding are also given during the explanation of the model. The paper also describes a reference architecture based on this model which can be found useful for the design of modelling tools, and a prototype application that helps understanding both the architecture and the model.

This paper proposed a new visual tag system for enhancing real world media interaction using handheld camera devices. This paper also described performance evaluations of the prototype, and its applications. C-Band is based on a ring with a color pattern code. A C-Band tag can provide a self-contained URL, and is flexible enough to allow various aesthetic designs for the tag’s surface. Furthermore, the tag’s structure is useful for building interactive techniques. Taken together, these features suggest that C-Band is an effective method to build various attractive camera-based media interactions.

This paper proposes a framework for VR application based on 3 different kinds of hierarchical structures for spatial, temporal, and semantic relationship. To achieve this, we incorporate scene graph, time graph, and ontology into the framework. This approach will enable to integrate synthetic space, real space, and knowledge seamlessly as a new way of developing immersive tangible space.

In this paper we describe our experiences and lessons learned from two user studies about the effects of short-term memory on data analysis tasks with graphical user interface and virtual environment. Visualization is a powerful tool for representing scientific data for analysis purpose. Current research progress enables us to create a high fidelity visual representation of scientific data. However, the value of traditional graphical user interface and Virtual Reality (VR) as human computer interface in data analysis via visualization tool is questioned by the domain scientists. We carried out two user studies that asked users to perform data analysis tasks. The first user study compared the user performance on selecting and manipulating transfer function (TF) with different graphical user interfaces in volume visualization to search certain structures within a 3D data set. The second user study investigated the performance difference of immersive VR, fish tank VR and haptic-based fish tank VR systems on four generic visualization tasks. The two user studies indicates that short-term memory plays an important role in 3D user interaction during data analysis task. The pitfall of 3D user interface design for scientific visualization is that too many efforts have been put into the interface itself or technology, rather than designing user interface to match or amplify human capabilities, for instance the limit amount of short term memory and its importance in data analysis process.

Navigation is a fundamental task in virtual environments. Some of the metaphors that are used to determine where users want to be placed at each moment are based on physical locomotion. Usually, these techniques require the use of several sensors and complex algorithms. In this paper, we present Super-Feet, a wireless navigation system controlled by natural movements without requiring invasive methods or devices. It uses a low-cost infra-red system to detect the instantaneous position of both feet and this information is translated into a walking and rotation velocity in the environment. Preliminary results show that Super-Feet navigation is more accurate but slower than joypad based navigation systems.

In stereo vision, the measurement of depth perception remains an enigmatic question. On the basis of geometric optics, numerous hypothesis and mathematical formulations have been proposed for explaining the mechanism of depth perception responsible of vertical exaggeration, although none of them have shown to be entirely satisfactory. We believe that stereo vision is not merely determined by geometry elements but also by mental factors that interact through a psychophysical process. Our initial observations refer to stereo-drawings that suggest a logarithmic correlation between real depth (stimulus) and perceptual depth (sensation), according to the psychophysical Fechner’s law. On this new approach, experimental data is being obtained in order to determine the Fechner’s constant for the sensorial modality of stereo vision, and to establish the logarithmic equation that rules the stereoscopic relationships between real and sensorial space. This equation might involve possibilities for technological developments, and it is the next step of our current research.

In the context of the optimization of the mechanical platform of a virtual reality system involving a haptic device, this paper introduces two tools in order to help the designer for obtaining the best positioning of the device respect to the application workspace. With this purpose we have defined a measure called Average Volumetric Manipulability, of how the application workspace fits in with the volume where haptic device provides its best performance. Also, we have defined other measure called Useful Manipulability which takes in account the frequency with which each zone of the application workspace is visited during the simulation process. The practical use of these measures is demonstrated using them during the design and development of a real application.