High-five is a physical communication in which two people tap their palms together at face level. Particularly in sports, high-five can share greetings, praise, and congratulations. However, recently physical contact, including high-five, has been limited due to COVID-19 pandemic. In this paper, we explore a possibility of “remote high-five” communication system using vibrotactile transmission. This system can measure and present vibration in addition to audiovisual information, allowing users to remotely share their emotions by sending and receiving tapping vibration like giving a high five. We also discussed cases where this system was actually used in sports scenes: family communication of athletes and sports viewing with hearing-impaired person.

We developed a vehicle ride simulation system for immersive virtual reality, consisting of a wheelchair for vibration and vestibular sensation, and a pedestal with a curved surface for the wheelchair to run on. Our unique combination of a wheel and a pedestal can present vibration and vestibular sensations of vehicle acceleration with simple, light-weight, and low-cost equipment. Our system was presented as a demonstration at an international conference for two examples of riding in a car and riding on a roller coaster. We provided 66 participants with a questionnaire to evaluate the quality of our system. Results showed that whole-body vibration by the actuator significantly improved immersion in the riding experience but could not reduce VR-sickness.

To clarify the spatial characteristics of wetness perception, we conducted two experiments to determine whether wet stimuli on the index and ring fingers affect the feeling of wetness in the middle finger of one hand. In Experiment 1, we tested whether the perception of dryness on the middle finger is affected by wet or dry stimuli on the outer two fingers. In Experiment 2, we evaluated the uniformity of the wetness perceived from three fingers when the middle and the outer two fingers were presented with stimuli with different degrees of wetness. Results showed that when the index and ring fingers contacted the wet stimuli, and the middle finger contacted the dry stimulus, the dry sensation of the middle finger was weakened. A uniform sensation of wetness was perceived. In contrast, when the outer two fingers contacted the dry stimuli and the middle finger contacted the wet stimulus, the wet sensation on the middle finger was not affected. These results suggest the phenomenon of “wet referral” exists among the fingers in one hand.

The robust sensory interface with limited information is demanded in virtual reality. In recent years, there has been an increasing amount of research applying the characteristics of integrated perception, which involves processing sensory information through the brain from the outside world to form perceptions and cognitions. This paper reviews the findings of synaesthesia, crossmodal correspondences, and multisensory integration, which is discussed as the integrated perception, from two perspectives: the characteristics and the underlying mechanisms. We also discussed the possibility of applying the findings of integrated perception to the multi-sensory interface.

The objective of the present study is the creation of sensation under turning walking using a vestibular display (a motion seat). We added a yaw-rotation mechanism to our three degrees of freedom (3-DOF) motion seat, with which we investigated the contribution of yaw rotation for the turning walking sensation. After an equivalent stimulus of the seat’s yaw rotation to a real left-turn walking was determined, the virtual turning walking sensation was rated by the user study. The result suggested that yaw rotation stimulation improved the sensation of turning walking by 1.6 to 2.2 times to the 3-DOF seat; the motion generated about 34.2% sensation of the actual walking.

In Japanese, we often use different onomatopoeias to express minute differences in viscoelasticity in daily life, but there are few studies that have clarified the relationship between the differences in tactile onomatopoeias and physical properties. The purpose of this study is to clarify the relationship between the differences in onomatopoeia and physical properties when expressing the softness of an object. In the experiment, two-dimensional movies showing different viscoelastic behaviors were used, and the subjects were asked to answer the onomatopoeia describing the tactile sensation of the images. From the experimental results, the relationship between the mora of the onomatopoeia and the physical properties was discussed.

When watching a 360° video with head-mounted display, viewers feel fear of missing out (FOMO). To reduce FOMO, we developed a technique to present a panoramic thumbnail of a full 360° video. With this technique, the user can grasp the overall view of the video as needed. Experiments comparing our technique to the normal viewing without the technique showed that the proposed technique can reduce FOMO without a negative impact on viewing experience. In addition, the behavioral data suggested that the participants used the panoramic thumbnail to actively search outside their field of view in exploratory videos.

This paper proposes a chair-based synesthetic experience device, Synesthesia X1-2.44, which utilizes auditory, haptic, and visual sensations. In order to realize a synesthetic experience, we designed the chair that includes 44 haptic actuators, two speakers and 5 stage lights, and exhibited it at Media Ambition Tokyo 2019. When discussing this work, we observed “sense of stretching and contracting of the body”, “sense of floating/sinking”, and “sense of disappearance of the body”. In addition, the combination of whole-body haptic sensation and spatial acoustics with sounds felt from inside/outside the body affects the autonomic nervous system and induces a pleasant state, and create a representation different from the usual auditory and haptic experiences.

The seated virtual reality (VR) has the advantage of not requiring large real space and much fatigue, but it has the problem that it is difficult to look around the entire virtual environment (VE) in a natural way due to the limited range of the neck movement. As a solution to this problem, rotation gains has been proposed, which amplifies the amount of head rotation in virtual space. However, previous studies have shown that this technique decreases the comfort and enjoyment of the VR experience. We assumed that this decrease was caused by the discrepancy between vision and proprioception. Therefore, we proposed a method of providing force feedback with a rubber band to improve the quality of VR experience with rotation gains. We conducted two experiments and showed that the appropriate strength of force feedback with a rubber band improved the naturalness of looking around in VE compared to the conventional rotation gains.

A method called redirected walking has been proposed to enable users to walk in a real space of limited size in a vast virtual space by manipulating the user’s direction and amount of movement. Three viewpoint manipulation methods, namely translation gain, rotation gain, and curvature gain, are mainly used in redirected walking. The rotation gain manipulates the user’s direction of travel by manipulating the rotation around the user’s head. However, when the rotation gain is applied to a user walking around a turn, the user’s walking path may deviate from the target. This deviation of the user’s walking path would be a serious problem, especially when interacting with real objects. To solve this problem, we propose a novel turning gain and correction method, which can control the user’s walking path even when the user turns without stopping.

Olfaction is a sensory modality that is easily modulated by other sensory stimuli. Odor impressions evoked by even one odorant differ depending on the temperature and humidity. In this paper, we investigate how odor impressions differ by presenting thermal stimuli and wind stimuli to the face. The effects of differences in the areas and positions of the stimuli are also investigated. The results show the factors that cause olfactory modulation are combined. In general, it is confirmed that olfactory modulation degree and odor impressions tend to differ depending on the presentation temperature when the stimuli are presented in a small area.

Conventional olfactory displays require the same number of odor sources as smells to be presented because “primary odors” that can represent all arbitrary odors in a combination do not exist. To solve this problem, olfactory displays that use crossmodal perception between other senses and olfaction have been proposed; however, the range of odors that can be represented from a few odor sources is still insufficient for practical use. In this study, we focus on the influence of nasal skin-temperature sensation on olfactory perception and proposed a novel olfactory-simulation method that combines visual presentation and nasal skin-temperature control. First, because the influence of the nasal skin-temperature sensation on olfactory perception has not been clarified, a user study was conducted to investigate its characteristics. The results suggested that the way odor changes by nasal skin-temperature control depends on the characteristics of the original odor source. Moreover, the change in perceived odor was similar if the characteristics of the original odor sources were similar. Second, the effectiveness of the proposed method was tested, and the results suggested that our method can extend the range of smells represented by a single odor source wider than existing methods.

The orthonasal and retronasal aromas are thought to affect odor-taste interactions differently. Many possible candidates can be postulated as cues for the identification of these aromas, and one of them is the kinetic sensation of breathing. However, in the previous study that investigated the relationship between breath and odor-taste interaction, the spout for presenting the odor stimulus was placed in the oral cavity during exhalation and the front of the nose during inhalation. This difference in placement results in significant differences in odor intensity between conditions. In addition, a tube in the oral cavity prevents food consumption and only allows participants to undergo experiments on the effects of odor while drinking. To investigate breath and odor-taste interaction, there is a need for a methodology that allows participants to stably smell when they are both breathing in and breathing out is needed. We placed the tube for presenting the odor stimulus in the nasal cavity and blocked the gap between the tube and the nostril. Participants consistently experienced smell stimuli during both inhalation and exhalation. We found that if the gap between the tube and the nostril are completely blocked, a insertion of less than 1cm of tubing is sufficient. Our novel methodology enabled the presentation of the smell perceived during exhalation and inhalation through a single nostril tube. More studies would be required to clarify whether the odor presented during exhalation in the present study was similar to the retronasal odor evaluated in previous studies.

In VR space, it is necessary to present the scent interactively according to time and location. Although it is possible to attach a scent presentation device to a head mounted display (HMD), some users would not prefer to wear any devices on their face. VR experiences without such a device require a method of presenting the scent locally. We previously proposed a scent presentation method using an air cannon that generates a vortex ring. In this study, we propose a novel configuration of an air cannon, CDA (Cluster Digital Air cannon). The CDA is composed of an aggregate of small-diameter holes, to synthetically forms an air cannon opening. By controlling the air pressure and opening time of valves, we achieved the velocity control of vortex rings and rapid shots. In addition, the size of air cannon can be shrunk because CDA, unlike conventional air cannon, does not need large inner volume. In this study, vortex ring generation by CDA was examined by computer fluid dynamics (CFD) simulation, as well as the vortex ring generation by the actual machine was performed. Furthermore, we verified that the scent was successfully presented by CDA.