It has been reported that even users of virtual environments and entertainment systems experience motion sickness. This
visually induced motion sickness (VIMS) is known to be caused by sensory conflict, for instance, the disagreement
between vergence and visual accommodation while viewing stereoscopic images. The simulator sickness questionnaire is
a well-known tool that is used herein for verifying the occurrence of VIMS. We used the SSQ and also quantitatively
measured head acceleration and sway of the center of gravity of the human body before and during the exposure to
stereoscopic images on a head-mounted display. During the measurement, the subjects were instructed to maintain the
Romberg posture for the first 60 s and a wide stance (with the midlines of heels 20 cm apart) for the next 60 s. We
proposed a method to obtain stochastic differential equations (SDEs) as a mathematical model of the body sway on the
basis of the stabilogram. While there are several minimal points of time-averaged potential function in the SDEs, the
exposure decreases the gradient of the potential function. We have succeeded in estimating the decrease in the gradient
of the potential function by using an index called sparse density.
In the present study, we examined the visual accommodation of subjects who were gazing fixedly at 3D images from two different displays: a cathode ray tube (CRT) while wearing special glasses and a liquid crystal display (LCD) while not wearing special glasses. The subjects were 3 people aged 20 years (2 people) and 36 years, all with normal vision. Visual function was tested using a custom-made apparatus (Nidek AR-1100). The instrument objectively measured
visual accommodative changes of the right eye in both binocular and natural viewing conditions. The target shown to subjects moved away slowly and disappeared at a distance about 3 m from the eye. The results suggested that it was easy and comfortable to focus on both the LCD and CRT. When the subjects viewed the progressively receding target, their accommodation was about 0.8 D at the presumed furthest points, a level at which the ciliary muscle is relaxed. The accommodative power differed by about 1.5 D from the near to far point. Thus, the ciliary muscle is repeatedly strained and relaxed while the subject views the moving target. In the present study, the subjects’ accommodative amplitude was changed when the target moved from the near to far point.
A design of prototype Infra-Red High-dispersion Spectrograph (IRHS) is described. IRHS is a cryogenic echelle spectrometer for 8.2-m Subaru Telescope, which will operate at 8 to 13 μm with resolving power of 200,000. To achieve such a high dispersion and broad bandwidth, a Germanium immersion echelle grating was adopted. As a preliminary step, we started to develop the proto-type of IRHS (ProtoIRHS) with currently available Ge immersion grating (30x30x72 mm) and one 512x412 Si:As impurity band detector array, which will provide the maximum resolving power of 50,000 at 10 μm with slit width of 0.612 arcseconds (0.48 mm) and two-pixels sampling.
We tested 130 subjects including elderly people using two types of stereogram. One was a 3D image of a repeating parallel pattern showing balloons, from a software program called Stretch Eye. This program adopts a shift method in which the balloons diverge just at the point that causes a single shift between the right and left eyes, so that they appear to be more distant than the monitor screen. The Stretch Eye image was shown on a color LCD. The other image was a paper stereogram. Both used the same image of balloons. Using these 2 types of 3D image, we analyzed the recognition of stereoscopic images among elderly people. The subjects were 130 people aged 18 to 86 years, including 60 people over 60 years of age. The subjects' visual functions of cataract cloudiness (CC) and pupil distance were measured. Comparisons were carried out for the two targets of the paper stereograms and color LCDs. Subjects were divided into four groups according to the severity of CC. Two-way ANOVA was used for the statistical analysis in order to compare the influence of the target types, age and cataract cloudiness on the ability, distance and time of stereoscopic recognition. In a two-way ANOVA, two kinds of dependant variables, recognized speed (RS) and recognized distance (RD) were used for the subjects' stereoscopic recognition performance.