In recent years, head mounted displays (HMDs) have become widely used among general users thanks to the release of low-cost and high-performance versions. It is expected that virtual reality (VR) experiences will often be performed in a relaxed posture, while sitting on a reclining seat at home or in the supine position on a bed in rehabilitation institutions. However, there is no clear knowledge on the subject of how humans perceive the horizontal plane of a virtual world while using HMDs in reclining postures. In this study, we investigated how the angle of the subjective horizontal plane changes in relation to the angle of the upper body in a reclining seat. As a result, we found that the angle of the perceived horizontal plane changes depending on the angle of the upper body, and the physical direction of gravity has little effect on this perception.

In cardiopulmonary resuscitation (CPR), the compression position is considered to be one of the factors affecting survival rate. We developed a CPR simulator called RibFracture CPR, which notifies a trainee through haptics when they are compressing in an inappropriate position by simulating rib fracture. Our system is expected to help trainees to smoothly adjust themselves for an actual CPR situation once they have undergone an initial training phase using visual feedback equipment. In this study, we investigated the accuracy of compression position one month after subjects learned the correct compression position using RibFracture CPR, and we evaluated the sustainability of the learning effect.

We have been investigating about the visual horizontal plane when wearing HMD. We investigated about the change of the visual horizontal plane in the reclining position and the upright position, but there is no clear knowledge as to whether the change in the subjective horizontal plane is due to the change of head angle or the change of posture. In this study, we investigate the effect of head angle on subjective horizontal plane in reclining position and upright position.

Recently, several virtual reality (VR) systems using wind have been built to enhance the user's sense of presence. If wind is used, users need not use additional devices, and some studies have concluded that using wind and presenting a video simultaneously improves this sense of presence. In these studies, however, wind sources were sparsely arranged; with such an arrangement, it is unclear whether an accurate environment was reproduced. A number of variables including gender, age, and the facial hit rate may affect the perception of wind direction. In the proposed study, we have examined the effect of these variables on perception of wind direction by the head.

In many cases, when we present a video to users, we present sound too. Hence, the senses of sight and hearing are stimulated, improving the users' sensation of presence. In addition, recently, several virtual reality systems using wind have been built to enhance this sense of presence. If we use wind, users do not need to use additional devices for sensing presence because in such cases, we can present them with non-contact sensations. Therefore, wind-based systems do not hamper an improvement in the sense of presence. In fact, some studies have concluded that presenting wind and video simultaneously improves the sense of presence. However, in these studies, wind sources were arranged rather sparsely. In this sparse arrangement, we are not sure whether a precise environment can be reproduced. Therefore, we have examined the perception of wind direction by the entire head.

A technique for locally distributing scented air and controlling its direction of movement is proposed. By causing two vortex rings carrying scented air to collide with each other, a local distribution of scent can be achieved in free space. Thus far, however, the behavior of scented air after vortex collision has not been controlled. In this study, we propose a method for varying the moving direction of scented air after the collision by precisely controlling the timing and velocity when expelling vortex rings. We conducted an initial experiment to examine the feasibility of this method and found that direction control of the airflow after vortex collision can be achieved by adjusting the velocity of vortex rings.

In this study, a hardware configuration for reducing the size of a scent projector is proposed, and its performance is examined using a prototype system. A scent projector is a system that delivers a small amount of scented air to the user's nose by channeling the scent through a vortex ring. A projector enables scents to be presented locally in time and space without requiring the user to wear any special apparatus. Such localization is important when scents are presented synchronously with other sensory stimuli. However, scent projectors make use of so-called “air cannons” that usually have significant volume, making their size a major drawback. To solve this problem, we examined the principal parameters that affect the performance of a scent projector, and found that the inner volume of the air cannon does not seriously affect the range of a vortex ring. Based on this analysis, we designed a flat-shaped scent projector that has zero volume in the idle state and built a prototype system. Our prototype performed almost as well as existing scent projectors with larger volume.

We propose a projection-based olfactory display method as an unencumbering way to deliver smells using a scent projector. This device allows us to deliver smells both spatially and temporally by carrying scented air within a vortex ring launched from an air cannon. However, our original scent projector had a problem: users often felt a significant, unnatural airflow when the vortex ring hit their faces. In this paper, we propose a novel configuration of a projection-based olfactory display that reduces this breeze effect. We use two air cannons that launch vortex rings that collide at a target point and break by themselves, distributing their smell at the point where they were broken to make a small "spot" of scent. With this configuration, users feel as if the smell came with a soft breeze, so that they can enjoy a more natural olfactory experience.

We present recent results we have obtained in the design of a wireless tactor system for use in virtual as well as real environments. We describe a system we have designed that uses vibration motors wired to a body-worn control box, which in turn communicates with a host computer using a wireless connection. Though we have successfully integrated this system into an existing VR-based dismounted infantry simulator, it is clear that expanding the body coverage and number of vibration points requires a solution that is completely wireless. To this end, we describe a working prototype we have built that, though still somewhat large and feature-limited, has convinced us of the merit of our approach.

This paper presents work we have done on the design and implementation of an untethered system to deliver haptic cues for use in immersive virtual environments through a body-worn garment. Our system can control a large number of body-worn vibration units, each with individually controllable vibration intensity. Several design iterations have helped us to refine the system and improve such aspects as robustness, ease of donning and doffing, weight, power consumption, cable management, and support for many different types of feedback units, such as pager motors, solenoids, and muffin fans. In addition, experience integrating the system into an advanced virtual reality system has helped define some of the design constraints for creating wearable solutions, and to further refine our implementation.

An interface that involves all five senses, including olfaction, would be the ultimate interface for virtual reality (VR). We are trying to construct an olfactory display that does not require the user to wear anything on the face. We used an "air cannon" to transport small packets of scented air to the user's nose from some nearby place. In this paper, we report the ongoing development of an olfactory display system with a nose-tracking feature by incorporating vision-based face tracking technology.

This paper presents results from two experiments into the use of vibrotactile cues for near-field haptics in virtual environments. In one experiment, subjects were tested on their ability to identify the location of a one-second vibrotactile stimulus presented to a single tactor of a 3-by-3 array on their back. We recorded an 84% correct identification rate. In a second experiment, subjects were asked to match the intensity of a vibrotactile stimulus presented at one location with the intensity at another location. We found that subjects could match the intensities to within 7Hz if the reference and adjustable stimuli were presented at the same location, but only to within 18Hz otherwise.

The Proactive Desk is a new digital desk with haptic feedback. The Proactive Desk allows a user to handle both virtual and real objects on a digital desk with a realistic feeling. We proposed it for a co-experience web that would enable people to share the feelings and experiences of other users via the Internet. In the Proactive Desk, two linear induction motors are equipped to generate an omnidirectional translational force on a user's hand or a physical object on the desk without any mechanical link nor wire, thereby preserving the advantages of a digital desk. In this paper we report applications of the Proactive Desk and the performance of the first trial model.

Proposes a novel visuo-haptic display using a head-mounted projector (HMP) with X'tal Vision (Crystal Vision) optics. Our goal is to develop a device which enables an observer to touch a virtual object just as it is seen. We describe in detail the design of an HMP with X'tal Vision, which is very suitable for augmented reality. For instance, the HMP makes the occlusion relationship between the virtual and the real environments nearly correct. Accordingly, the user can observe his/her real hand with the virtual objects. Furthermore, the HMP reduces eye fatigue because of the low inconsistency of accommodation and convergence. Therefore, we applied HMP-model 2 to a visuo-haptic display using a camouflage technique. This technique, called optical camouflage, makes an obstacle object, such as a haptic display, become translucent. With this method, a user can observe a stereoscopic virtual object with a nearly correct occlusion relationship between the virtual and the real environments, and he can actually feel the object.

Projection-based visual display systems are expected to be effective platforms for virtual reality (VR) applications in which the displayed images are generated by computer graphics using 3D models of virtual worlds. However, these kinds of visual displays, as well as other kinds of fixed screen-based displays, such as various head-tracked displays (HTDs) and conventional CRT displays, have not been utilized to achieve precise telexistence in a real environment, which requires appropriate stereoscopic video images corresponding to the operator's head motion. We found that the time-varying off-axis projection required in these systems has prevented fixed screen-based displays from being used for telexistence, as ordinary cameras only have fixed and symmetric fields of view about the optical axis. After evaluating the problem, a method to realize a live video-based telexistence system with a fixed screen is proposed, aiming to provide the operator with a natural 3D sensation of presence. The key component of our method is a feature that keeps the orientation of the cameras fixed, regardless of the operator's head motion. Such a feature was implemented by designing a constant-orientation link mechanism.