Hironori Mitake

With a spread of inexpensive and easy-to-use motion tracking methods such as cameras and trackers for virtual realities (VRs), real-time motion-tracked avatars are becoming increasingly common in virtual environments, particularly social VRs, virtual performers (e.g., virtual YouTubers), and VR games. These applications frequently involve interactions among multiple avatars or between avatars and objects for communication or gameplay. However, at present, most applications do not sufficiently consider the effects of contact for avatars, thus leading to penetration or unnatural behavior. To achieve natural avatar motion in such scenarios, the player must perform as if contact has occurred, even though, in reality, there is no contact with the player’s body. While physics simulation can solve the contact issue, the basic use of physics simulation causes tracking delay. We therefore solve this tracking delay problem by employing Featherstone’s algorithm, a reduced-coordinate method for forward dynamics, and by utilizing the Newton-Euler formulation for inverse dynamics to compute tracking forces and torques. To evaluate the delay, we measured the difference between the joint rotations of the simulated model and the input joint rotations. The evaluation with our method indicates the difference is less than 1.4 micro radians for all joints in real time with a small computational cost. Moreover, accurate tracking enables the fixation of both feet. The proposed method provides accurate tracking and soft reactions to contact.

We propose “Tellipsoid”, an ellipsoidal display for the video conference system, that can realize not only accurate eye gaze transmission but also practicality in conferences, namely the convenience and the identity of the displayed face. The display consists of an ellipsoidal screen, small projector and convex mirror, where the bottom-installed projector projects the facial image of a remote participant onto the screen via the convex mirror.

Investigation of human thermal perception concerning a thermal display is important for designing a better interface. However, research about human perception characteristics for a thermal display using radiant heat has not been conducted so much. In this study, we examined human thermal perception when the palm was irradiated by visible light. Firstly, we compared temperature distribution in case of a peltier device and the visible light LEDs. The result showed that the temperature distribution of the LEDs was ununiform. Secondly, we revealed the minimum temperature where a human can feel the warmth on the skin. As a result, the required minimum temperature of the visible light LEDs to feel warmth is higher than that of a contact type thermal display. The result indicates that the difference between deep body temperature and skin temperature became small and that influences human thermal perception since visible light is absorbed into melanin and hemoglobin well.