Vection is an illusory self-motion perception induced by coherent motion in a wide visual field. We measured vection for two kinds of subjects who could or could not control the optic flows (the driver and passenger). Vection strength was always stronger in the passengers than in the drivers. These results could be explained by the predictability of the optic flow and active behavior with correct feedback.
We used a questionnaire to investigate how non-researchers conceptualize sense of presence. Respondents were 108 students with no professional education related to engineering or virtual reality. More than 90% of the respondents knew of the term, but they tended to use sense of presence not only to refer to a subjective experience of being there in a mediated environment, but also to refer to an experience that makes them feel excited or as having an extraordinary experience in an actual environment. Factor analysis revealed four sense of presence components: evaluation, impact, activity, and mechanicalness. Events with high presence were likely to be evaluated as preferred, impressive, and dynamic. Furthermore, the participants estimated that distal and proprioceptive sensors such as vision, audition, equilibrium, and kinesthesis were closely related to a sense of presence. These results suggest that sense of presence is not a single and simple concept for non-researchers, but is instead an ambiguous and the multidimensional construct with modality-selectivity. These aspects of sense of presence must be considered in specifying physical factors for high presence and establishing objective measures of sense of presence.
'Sensory conflict' theory is one of well-known theories for motion sickness. We conducted two experiments to determine the effects of the conflict between actual (extra-retinal) eye-movement and visually-simulated (retinal) eye-movement on motion sickness in a virtual environment. In results, we found that motion sickness was significantly decreased by controlling observers' eye-movement with a stationary/moving fixation point. When the extra-retinal and the retinal eye-movements were incongruent during the observer's head moving, the motion sickness was increased for sickness-sensitive observers. These results suggest that we can decrease motion sickness by controlling eye-movements with a stationary/moving fixation point to remove conflict between the extra-retinal and the visual eye-movements. This proposal represents a new approach to decreasing or preventing motion sickness in virtual environments.
This study examined the influence of visual inducing stimulus on choice tasks in a computer. Subjects were asked making a series of choices to be random order for two items presented repeatedly on the computer screen. At some choices, an inducer (an arrow or a CG character) was appeared at the center between two items and indicated either item. Results showed that subjects tended to avoid the item indicated by the inducer, especially when the inducer was the arrow. The phenomenon is similar to psychological reactance to restore the freedom from a restricted circumstance. Moreover, the strength of the reactance depended on subject's personality trait "openness to experience" measured in big-five scale.
We aimed to develop a driving simulator that can be steered by neural signals without handling a steering wheel. It will be a pre-prototype of future vehicles utilizing human psychological and physiological information. We developed a driving simulator that uses steady-state visual evoked potentials (SSVEP) to control steering. First, we conducted a basic experiment to measure SSVEPs using two flickering checker patterns, which were located apart right and left and had different reversal frequencies. When observers looked at one of 7 positions between two checkers, observers' SSVEPs quantitatively changed depending on the distance between the fixation point and the left/right checkers. Then, we made a simple algorithm to calculate a steering angle from SSVEPs, and applied it to a driving simulator. Some naive drivers could steer a car only with SSVEPs along a curving course in real-time. However, there were large individual differences and instabilities of performance across different courses.
This paper investigated the effects of active/passive viewing on the visually induced motion sickness. Participants wearing a Head-Mount-Display (HMD) searched a target character in random dots and other characters projected on a screen using a video camera moved by them (active viewing). They could see a part of the screen and the movies displayed via the HMD were recorded. When they saw the recorded movie later (passive viewing) through the HMD, they felt motion sickness worth than before. This suggests that passive viewing induced severer motion sickness than active viewing.
To reveal proficiency of trainees in executing of VR training system simulated for real works, relative fluctuation of hemoglobin concentration in prefrontal cortex of nine healthy subjects as well as time required for dose measurement, were investigated in five experiments by using a video camera and a NIRS system. For the purpose of describing prefrontal cortex activation represented by oxy-hemoglobin concentration, the authors originally proposed the event-related index (called ER index) derived from activation of oxy-hemoglobin concentration during dose measurements. As the result of statistical analysis, it was confirmed that average time required for dose measurement and the ER index simultaneously decreased in the second experiment. According to this result and the previous studies for prefrontal cortex functions, the subjects came to the early proficient stage for dose measurement works demonstrated in the VR training system. Therefore, the ER index proposed in this study was consequently considered to be useful for proficiency evaluation of trainees in executing VR training system.
While a walk-in-place locomotion interface which uses human steps has the advantages of being smaller devices as well as allowing users to intuitively control speed, previous methods are limited to forward motion, and has other problems such as time lags and a tendency to be easily damaged. The current research uses two wireless accelerometers attached to the user's hips, and a geomagnetic sensor attached to the user's trunk to allow intuitive control of stepping forward/backward, jumping and change of direction through the user's actual actions of stepping forward/backward, jumping and body-twisting. We report the algorithms used, as well as a prototype system built for the present research.
In this paper, a haptic rendering system for a virtual control panel using an encountered-type haptic device is presented. The system can render different switches on a panel in virtual space by a single haptic device. A motion planning algorithm of the encountered-type haptic device is proposed in order that the device is properly encountered by the user's finger at the switch locations while it avoiding unintended collisions against the user elsewhere. Two improvements are made to the previously proposed motion planning algorithm. The one is refinement on the weighting function in the algorithm to reduce the duty of the device motion. The other is introducing virtual surface coordinates to the motion planning so that unintended collisions of the device against the user are completely avoided in free space. The proposed method is verified by numerical simulation.
We present a media art work "Mysterious POND", which gives a mysterious illusion for multiple users on a digital table using a revolving polarizer. It normally shows users a waving water surface, but only the users embodying "Sansai ", an oriental philosophy, can watch carps in underwater by illuminating the water surface with a magic lantern. For embodying "Sansai", the user needs to be under the sun or the moon, and wear glasses. This paper describes the theory and its implementation of Mysterious POND, followed by some sceneries of the demonstrations. Finally, the future extensions of the work are discussed from the results of the demonstrations.
3D mesh models generated with a range scanner or video images often have holes due to occlusions by other objects and the object itself. This paper proposes a novel method to fill in the missing regions in incomplete models. The missing regions are filled in by minimizing an energy function that is defined based on the similarity of local shapes between the missing region and the rest of the object. The proposed method can generate complex and consistent shapes in the missing region. In experiments, the effectiveness of the proposed method is successfully demonstrated by applying it to various objects with missing regions.
This study demonstrates a method to calculate a topological change of a finite element model with a fracture phenomenon in real-time. The method reduces restructuring calculation costs for a topological change by restructuring only the local region near the crack-tip. Also, the method presents reaction forces that reflect topological changes to the user through the interpolating pre-calculated reaction forces data. The developed system demonstrated that the proposed method enables the calculation of a topological change in real-time. The time required to conduct the restructuring calculation in the proposed method was shorter than that of the conventional method. Additionally, the errors from the proposed interpolation method were smaller than the errors from methods without interpolation. As a result, the effectiveness of the proposed method was demonstrated.
The motivation for this work is that understanding of the perceptual response could guide to development of highly realistic tactile displays. The term "memory tactile" is used here in the same way as memory color to describe tactile senses that are recalled in association with familiar objects which we frequently touch in our daily life. We carried out an experiment using a standard hardness of pencils to investigate how the remembered tactile differs from the actual hardness. As a result, the rise of hardness in the remembered tactile was confirmed, and it suggests the similar existence of memory tactile to the memory color.