The saliva secretion system has many important roles for our life, such as maintaining oral condition, smoothing speech, support eating and swallowing and others. The saliva section involves emotion and eating and drinking experience. Thus, digital technology to control saliva secretion would be an effective tool to affect VR experience. Previous studies conducted in the fields of dental health show that electrical stimulation inside or near the mouth promotes saliva secretion after long durational stimulation. However, in terms of VR use case, the effect should occur during stimulation and preferred to affect strongly. Therefore, we developed a novel stimulation method to effectively promote human saliva secretion using finite element analysis. And then, the effect of the stimulation method were quantitatively evaluated the effect during stimulation.

The virtual image presented with Augmented Reality (AR) device is superimposed on the real world, and we can perceive it as if actually existing there. However, it is still unclear whether we could perceive a virtual image with the setting values for depth (distance and size). In this study, we examined the basic characteristics of depth perception for the AR images by the adjustment method (compared between an AR object and a real object) and the constant method (compared between an AR object and reference of distance). The results of experiments showed the overestimation of depth for a virtual image. In addition, the monocular observation would induce much overestimation than the binocular observation, while the sensitivity of depth improved with occlusion for another side of the eye where the virtual image was not presented. These results would help more appropriate presentation of the virtual image in the AR devices.

We propose a configuration that combines a conventional video call system and a contour-based projected hand by a laser scanning projector that works in a bright room. To increase the presence of the projected hand in the remote site, we focus on the projected hand’s visual effects. From the perspective of minimal design, we confirmed the importance of minimal design for the palm shape of the contour-based projected hand. In addition, we investigated the characteristics of promising hovering and contact states on the contour-based projected hand. As a result, we confirmed that the shadow effect and the transition expression from hovering to contact were suitable for expressing hovering and contact with the contour-based projected hand.