This paper describes about spherical immersive display using convex mirror. Our display provides seamless image that totally surrounds a viewer. In order to construct the system, we designed optical configuration of display through the virtual projector that simulates behavior of projected light. The prototype display based on the optical design provides 360 degree horizontal and 115 degree vertical image. This optical configuration has an advantage in displaying video image. Then we also developed a camera head with convex mirror, which corrects distortion of displayed image.

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We propose a 3-D modeler which can design and manipulate 3-D geometry in CAVE. In this system, two new techniques which can support modeling operations in a virtual environment are proposed. One is the technique which realizes the intuitive operation using a pen-type input device and simple gestures. The other is the technique in which operators can control the constraint condition dynamically according to their gestures and geometric characteristics of virtual objects. These techniques are very important to apply a high degree of freedom which is a merit of virtual environments to modeling operations. With this system, the operator can design 3-D objects more intuitively and more efficiently in a virtual environment.

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When people have casual meetings, it is not unusual that several participants sit around a table and point at and manipulate artifacts on a desktop. Such collaboration includes collaborative design activity with sheets of paper and collaborative learning using tangible device. We are interested in supporting this kind of collaboration in remote setting. In this paper we introduce the video mediated remote collaboration system. This system is designed so that embodiment of participants' conducts can be monitored naturally. To allow a system at least four participants, we employed the roundtable meeting metaphor. Two 60-inch screens are settled along two side of each desk. Images of remote participants are projected onto the screens. Artifacts and gestures on both desktop are shared by using a similar configuration to Double DigitalDesk. In this paper, we describe design principle, architecture, and initial impressions of the system.

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Visual motions in large region, retinal periphery, and in far depth elicit the inevitable perception of self motion (vection) in the opposite direction to those visual motions. We investigated whether voluntary attention affects the perceived vection direction. The opponent-directional motions were presented on a CAVE-type display where the size, the eccentricity, and the depth were identical in opponent motions. The subject was instructed to pay attention to one direction of visual motion and to judge the perceived vection direction. Vection was perceived in the direction opposite to the non-attended motion, indicating the non-attended motion dominates vection. Next, attentional effect on the uni-directional motion was compared with that on the opponent motions. In the uni-directional-motion condition, the vection was perceived in the opposite direction to the attended motion or the whole motion. This is consistent with the previous findings without attention manipulation. The present study suggested that the attentional modulation of the vection occurs when the opponent-directional motions were applied or the visual motion has unstable components.

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In this paper, a wireless and lightweight interface A-MUSE(Active emission tracking system in MUltiscreen Environment), which makes it possible to use without preventing users' illusion of immersion in large-scale VR(Virtual Reality) systems such as CAVE(CAVE Automatic Virtual Environment), is proposed. A-MUSE measures 6DOF(degrees of freedom) which are position and direction of the device. It projects five pairs of rays onto screens and then it measures 6DOF from geometrical relation between the initial and the transmitted state. It also possible to use several devices simultaneously. By using projective transformation invariants of five pairs of rays, A-MUSE makes a correspondence of rays between the initial and transmitted state. The correspondence process includes two steps. One is to detect a pair of rays projected from one device among a large number of rays. The other is to correspond each ray in the initial state to a ray in the pair of transmitted rays. The computational complexity of the process is n^5 order of the number of devices. Therefore, acceleration of the process is proposed by setting some restrictions to the process. Moreover, error reduction method is proposed for the practical use of A-MUSE in order to reduce the error occurred from several factors. It gives restriction to a matrix used for measuring of 6DOF. Finally, in order to evaluate the proposed system, A-MUSE is compared with the alternating current magnetic sensor which is usually used in CAVE. The measuring results of A-MUSE is more precise than that of magnetic sensor.

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We have applied virtual reality technology to an electric power plant training environment. Virtual reality systems with multiple projectors to provide sense of presence in a wide view environment were large-scale, complicated and expensive. Therefore, we developed a virtual reality system with a small cylindrical screen in order to provide a wide view field using one projector, as well as joystick control methods for this training environment.

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The multi-screen display using video projector has concerned interest and become popular for virtual reality display. In this paper, we discuss a visual effects that depends on the number of screens of a cubic display and report a development of COSMOS. COSMOS is a CAVE-like 6 screen display and the user is surrounded by screens completely. We examined a visual effect of multi-screen display and confirmed that the 6 screen display has an outstanding visual effect comparing to display that has less than 6 screens. By using the COSMOS, we investigated the effects of full immersion in the large scale virtual space navigation. The result suggests that the changes from 5 screens to 6 screens are not only "quantitative difference" but also "qualitative difference".

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Visual display systems based on Immersive Projection Technology, such as CAVE and CABIN, are considered to be effective platforms for VR applications. However, these kinds of visual displays, as well as conventional CRT displays and other kinds of Head-Tracked Displays, have not been utilized for exact telexistence in real environment, which requires appropriate stereoscopic image sequences reflecting the operator's head motion. In this paper, a method to provide the operator with natural three-dimensional sensation of presence using a fixed screen is presented, focusing on the consistency of the perspective transform performed at remote site and the operator's site.

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We developed of VR presentation system with a spherical screen which covers our whole view, and we can experience and construct together what an ideal urban development planning. This development is one of the target of National project by MITI named Urban Environment Human Media. In this paper we introduce a spherical screen and this characteristics, and hardware configuration. Then we describe image correction method to map graphics on a spherical screen.

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Because the field of view of Head Mounted Display(HMD) is narrow, you have to look around by moving your head widely to recognize the situation of the environment. But in real world, without HMD, you can see and recognize the world at a glance. So it can be expected that the way of recognition of the presented virtual environment is not same as that in real world. And more, the internal spatial model of the virtual environment may be not accurate. In this paper, the risk of a mistake of recognizing the virtual environment by using HMD was discussed. As the result of experiments, by using an HMD with narrow field of view, the importance of the somatosensory information and wide view visual information were suggested.head mounted display

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In a virtual reality system with a glove-based input device, the time lag affects the usability of direct manipulation of virtual objects. To find out how to improve the usability, we conducted two empirical studies. The experimental results show that visibility of a real hand is effective for improving both manipulation efficiency and manipulation feeling. Also shown is that visual feedback hardly affects manipulation efficiency, though it improves manipulation feeling.

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In this paper, the implementation of visual and haptic feedback of deforming and cutting operations is discussed. In the implementation of the deforming operation, the surface shape is represented by a geometric model while the physical reaction is simulated using a spring model. The deformation of the spring model is considered on the geometric model by using interpolation technique. In the implementation of the cutting operation, we realized visual and haptic feedback of the cutting operation remarking on the geometric and physical aspects, respectively. Combining the deforming and the cutting environment, we successfully implemented a work space in which we can form and design shapes through operations similar to clay modeling.

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