NICT has developed a multi-view 3D video display system with a 200-inch screen (REI display). In this system, several viewers can simultaneously view natural 3D objects from their respective viewing positions without special glasses. We proposed a 3D audio system using multiple vertical panning (MVP), which is compatible with REI display systems. However, the practical realization of our proposed system is obstructed by the assumption that the position of its sound sources is continuous. In this paper, to develop a practical system, we evaluated the effect of the discretization of sound source positions on the sense of presence by performing two audio-visual psychological experiments where the horizontal and vertical positions of sound sources were discretized. 3D videos were presented to viewers wearing glasses in both experiments. The results of the first experiment showed that viewers failed to discriminate differences of the sense of presence with ten or more loudspeakers. In the second experiment, viewers failed to discriminate differences of the sense of presence even if the vertical position of the sound sources was discretized with two steps. We conclude that a practical system using our proposed system can be constructed with five horizontal and two vertical steps of sound source positions.

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A parametric loudspeaker has a higher directivity by utilizing an ultrasound wave and can form a spatial narrow audible area called "audio spot" to a particular listener. However, it is difficult for a single parametric loudspeaker to transmit the same target sound to several listeners in particular area. To solve this problem, we propose a control of audio spot with a flexible parametric loudspeaker. The flexible parametric loudspeaker has concave-surface arrangements of ultrasonic transducers and can steer the directivity by controlling its curvature flexibly. As a result of evaluation experiment, we confirmed the flexible parametric loudspeaker can control an audio spot according to position and number of listeners.

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Understanding the mechanism of virtual reality perception is crucial for the development of high-definition communication systems in multimedia contents. Recent results show that the perception of reality can be enhanced by not only audio-visual contents but adding full-body vibratory information. However, the effects of stimulus onset asynchrony (SOA) on reality perception have not been clearly understood. In this study, we investigated the effects of audio-visual SOA and visual-vibratory SOA on the intensity of reality perception. Results indicated that reality perception was more sensitive to audio-visual SOA than to visual-vibratory SOA.

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We present the FuwaFuwa sensor module, a round, hand-size, wireless device for measuring the shape deformations of soft objects such as cushions and plush toys. It can be embedded in typical soft objects in the household without complex installation procedures and without spoiling the softness of the object because it requires no physical connection. Six LEDs in the module emit IR light in six orthogonal directions, and six corresponding photosensors measure the reflected light energy. One can easily convert almost any soft object into a touch-input device that can detect both touch position and surface displacement by embedding multiple FuwaFuwa sensor modules in the object. A variety of example applications illustrate the utility of the FuwaFuwa sensor module. An evaluation of the proposed deformation measurement technique confirms its effectiveness.

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Galvanic Vestibular Stimulation (GVS) can present left/right, front/back and left/right yaw acceleration sensation. It is known that the acceleration is produced towards anode from cathode. However, presenting superior-inferior directional acceleration sensation is not reported. It seems that current path in the head is not well understood and that gravity acceleration masks the perception of weak acceleration sensation even though it evoked superior-inferior acceleration within the GVS safety guideline. Therefore, we invented the stimulation method that can make subjects feel inferior-superior acceleration sensation within the safety guideline by applying inferior-superior direction countercurrent that can present strong inferior-superior directional acceleration sensation passing through the holes of temporal bone. The effects of inferior-posterior directional countercurrent were investigated by measuring subjective acceleration perception and body sway.

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We propose a puppet-based user interface - named Avatouch - for specifying massage position without looking at the control device. Users can indicate massage position on their backs by touching the puppet's one (Figurel). Besides, we also develop a massage chair system with both a push-button interface and Avatouch. Experimental results confirm that almost half of subjects kept Avatouch well away from their faces. Furthermore, two participants modulated massage position without looking at the plushie. In this paper, we firstly explain about Avatouch. Then, we describe a massage chair system and a user study to observe how people use each interface. At the end of this paper, we will discuss the advantage and disadvantage of Avatouch.

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In this work, we demonstrated that cathodal direct current stimulation to the tongue inhibits salty and umami perception and investigated the relationship between magnitude of current and the effect size of the taste suppression. The acknowledgement from our work would contribute to the virtual reality and human health fields e.g., any tastes can be presented to human virtually and tastes modification would assist the diet.

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We manipulate equipment naturally as an extension of physical ability. However, it is unclear whether we can transform supernumerary body parts to our body image to use the equipment as a similar body parts. So, this study suggests that ownership is formed by the simultaneity of visual and tactile stimulation, and that this perception of ownership is important to form the body image. In addition, we propose that if the equipment appears to be extended continuously from our body and ownership of the equipment occurs, then the body image will be transformed to include the equipment. Therefore, in this study, the equipment was arranged to appear as extending from the body, and visual and tactile stimulation were used to elicit ownership of the equipment. The results confirmed that body image was transformed to include the equipment. Furthermore, this suggested that it is possible to incorporate equipment into one's body image, and that we could use the equipment as a supernumerary our own body-part.

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We investigated no-disparity realistic (NDR) images for perceived image-quality and visual fatigue. NDR images are composed of left and right images. The right image is created by shifting the left image. NDR images are images with no disparity in any area. A stereoscopic effect is expected from this imaging method to render a picture-frame and large-screen effect. In experiment 1, subjects observed still images of both NDR and stereoscopic type and answered questionnaires on realism, SSQ and VAS. In experiment 2, the subjects viewed videos, and 2D video condition was newly provided. Based on the questionnaires on realism conducted in experiments 1 and 2, we found that while the NDR images had a weaker stereoscopic effect than that of stereoscopic images, the former were more natural and easy to watch. We also found that NDR images rendered visual fatigue than that caused by 2D images and lower than that caused by stereoscopic images. The NDR images demonstrated a higher stereoscopic effect than that of 2D images by providing a picture-frame and large-screen effect.

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In this paper, we aim to manipulate user's perceived shape of a curved surface by using pseudo-haptics in projection-based mixed reality. We investigate how we can change the shape which a user feels when touching a curved surface with an index finger, by projecting his/her shifted hand image onto the user's own hand. We performed experiments to investigate the effects of pseudo-haptics and evaluated their influences. The results showed that the shape which the participants perceived was deformed from the actual shape they touched. The results prove the possibility for manipulating user's perceived shape of a curved surface by using pseudo-haptics in projection-based mixed reality.

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