In our previous study (Seno & Yoshinaga, 2016), we suggested the immersion vection stimulus which VR system reflects observer’s motion real-timely to. In this study, we developed a wearable virtual earthquake demonstration system with the immersion vection stimulus and Google Cardbord VR system. We further developed our Virtual Earthquake into SR content. We also conducted Psychological experiments to evaluate and estimate our systems.
Sense which is experienced one body as own body is called sense of body ownership. Normally, we perceive a sense of body ownership over own body. Nevertheless, previous work has reported we can experience avatar as own body. This illusion is called Body Ownership Illusion. Our research investigated relationship with visuo-motor synchrony, perspective and avatar's height in terms of sense of body ownership. Our findings result in visuo-motor synchrony and first person perspective are main factor regarding inducing sense of body ownership over bird avatar.
In some phenomena of visual perception, the visual system shows different behavior in oblique directions from the cardinal (vertical and horizontal) directions, and it is called “Oblique effect”. In this study, we investigated the oblique effect of vection strength. Random dot optical flows which moved in 16 directions (0, ±20, ±45, ±60, ±90, ±120, ±135, ±150, 180°) on the frontal parallel plane were used as stimuli, and vection strengths (latency, duration and magnitude) were measured for each direction. The results significantly indicated that vection strength in oblique direction was weaker than the cardinal directions.
We investigated whether strength of vection could be modulated by a change in subjective stimulus region with the physical region kept constant. Amodal completion of a motion stimulus behind subjective figures enlarged the subjective region of the stimulus. We measured vection, manipulating the existence of amodal completion. The results show that the subjectively enlarged stimulus enhanced vection induction even when the depth information of the motion stimulus was constant.
It was shown that the self-motion perception (i.e., vection) with cutaneous inputs was influenced by the “change” (with or without) of the wind intensity which is applied to the participants’ face.(Murata et al., 2015). The present study aimed to investigate whether the change of the cutaneous intensity (“approaching to” or “leaving from” the wind source) would also influence the vection. The former condition is that the source itself was moved to the participant sitting on an aero bike (which is placed on a board). The latter condition is that the source was moved away from the participant. In both conditions, the wind intensity was manipulated by continuously changing the distance from the source to the face. A constant vibration was applied to the participants via the board in such a way that the participants received simulated vestibular stimulations. The latency and duration were measured as indices of the vection. The result showed that the vection appeared to be faster in the “leaving” condition compared to the “approaching” condition.
Murata et al. (2014) reported the wind for cutaneous sensation with vibration for vestibule could occur perceived self-motion. The authors of this study have compared perceived self-motion by cutaneous sensation with actual body transfer. Komatsu et al. (2015) found the occurrence of perceived self-motion was facilitated when the direction of wind was corresponded with the direction of transfer. This study investigated the condition that the wind from front and behind blew at the same time.
We examined the effects of sole vibration on the visually induced self-motion perception (known as ‘vection’).We measured the strength of vection when sole vibration and/or visual oscillation were added to the optic flow simulating the observer’s forward translation. The results showed that the strength of vection did not change when both sole vibration and visual oscillation were added, and that the strength of vection decreased when either sole vibration or visual oscillation was added. These results suggest that the consistency between visual and sole sensory inputs influences the strength of vection.
Body ownership illusions typified by the rubber hand illusion (RHI) have been gaining attention as a phenomenon that directly shows the considerable flexibility of our brain, even on the perception of our own body. Since such illusion occurs when an individual is feeling an integration of own body with other’s body, the perception of other’s body could be altered in some ways under the illusion. Here we investigated how an RHI-like illusion affects the perception of other’s motions, by comparing the performance of detecting finger movement change between two conditions, under illusion and non-illusion. We created a dummy hand in a virtual space using 3-dimensional computer graphics and induced the RHI-like illusion over the hand of the subject by producing visuo-tactile stimulation with a computer-generated animation and a vibration motor. The subject’s task was to detect a small change in motion which was randomly inserted into the repeating cycles of finger movements. Regardless of the fact that there was no visual difference between the two conditions, the detection performance was higher under body ownership transfer illusion. The result suggests that body ownership transfer has an effect on the visual perception of other’s motion.
To examine the interaction among binocular disparity, motion parallax, and relative size cue for perceiving large depth, we quantified the apparent depth from these cues using a matching method. When only one of these cues was given, apparent depth was tiny. When the depth was specified by both binocular disparity and motion parallax, perceived depth was small again. However, adding relative size cue to binocular disparity and/or motion parallax expanded apparent depth much. These results suggest that the interaction between relative size cue and binocular disparity or motion parallax plays a major roll for perceiving large depth.
Benham’s top makes the observer perceive apparent color when it is spinning. Our new finding is that the perceived length of a line segment is clearly enlarged. We examined three factors of stimuli (line style, position of the line, and background color of the line), and the length illusion in two ways in order to understand the perceptual mechanism; line segment length (magnitude estimation task) and endpoint location (alignment task using other rotating marks outside the disk). Experiments show that the perceived “line segment length” is clearly elongated in the “rear / white-background” condition (max 11 deg. at 60 rpm) whereas the “endpoint location” is mostly correct (max 2.6 deg. at 40 rpm). Results suggest that the length illusion occurs (1) at a relatively high perceptual stage, and (2) only at the white-to-black transition on the white sector.