Hiromu Ishio

Simultaneous measurement of lens accommodation and convergence to real objects

Human beings can perceive that objects are three-dimensional (3D). as a result of simultaneous lens accommodation and convergence on objects, which is possible because humans can see so that parallax occurs with the right and left eye. Virtual images are perceived via the same mechanism, but the influence of binocular vision on human visual function is insufficiently understood. In this study, we developed a method to simultaneously measure accommodation and convergence in order to provide further support for our previous research findings. We also measured accommodation and convergence in natural vision to confirm that these measurements are correct. As a result, we found that both accommodation and convergence were consistent with the distance from the subject to the object. Therefore, it can be said that the present measurement method is an effective technique for the measurement of visual function, and that even during stereoscopic vision correct values can be obtained.

Stereoscopic vision induced by parallax images on HMD and its influence on visual functions

Visual function of lens accommodation was measured while subjects used stereoscopic vision in a head mounted display (HMD). Eyesight with stereoscopic Landolt ring images displayed on HMD was also studied. In addition, the recognized size of virtual stereoscopic images was estimated using the HMD. Accommodation to virtual objects was seen when subjects viewed stereoscopic images of 3D computer graphics, but not when the images were displayed without appropriate binocular parallax. This suggests that stereoscopic moving images on HMD induced the visual accommodation. Accommodation should be adjusted to the position of virtual stereoscopic images induced by parallax. The difference in the distances of the focused display and stereoscopic image may cause visual load. However, an experiment showed that Landolt rings of almost the same size were distinguished regardless of virtual distance of 3D images if the parallax was not larger than the fusional upper limit. However, congruent figures that were simply shifted to cause parallax were seen to be larger as the distance to the virtual image became longer. The results of this study suggest that stereoscopic moving images on HMD induced the visual accommodation by expansion and contraction of the ciliary muscle, which was synchronized with convergence. Appropriate parallax of stereoscopic vision should not reduce the visibility of stereoscopic virtual objects. The recognized size of the stereoscopic images was influenced by the distance of the virtual image from display.

Visibility Experiment and Evaluation of 3D Character Representation on Mobile Displays

In the experimental study, we measured visibility and readability of text characters presented on a small 3D liquid crystal display (LCD) and evaluated features of the 3D character representation for application to mobile devices. For the visibility evaluation, we focused on time lag for first recognition, time required for full reading, and maximum distance of 3D objects popping out from the fixed display. We also report the dependency of the results on the age of subjects in comparison with 2D and 3D representations.

Measurement of Lens Focus Adjustment While Wearing a See-Through Head-Mounted Display

In recent years, many visual devices have been produced for consumers. The development of see-through smart glasses has attracted much attention. These glasses overlap virtually images by using Augmented Reality (AR) technology. Epson released the BT-2000 see-through smart glasses, which change distance of display by changing convergence. It is not confirmed that changing distance of display allow to change distance of lends accommodation. In this experiment, we measured lens accommodation of subjects viewing images displayed on see-through smart glasses. The results found that lens accommodation moved with the image position for over one hundred people. Therefore, our study verified that correct reaction occurred visual physiologically.

Nodal-line densities of chaotic quantum billiard modes satisfying mixed boundary conditions

Statistics of nodal lines for eigenmodes u in the stadium are computed, and compared with previously derived formulae for monochromatic boundary-adapted Gaussian random waves in the plane. These modes and random waves satisfy the Helmholtz equation, and mixed boundary conditions in which a linear combination of u and its normal derivative must vanish. For the density of nodal lines, and the excess density of nodal lines arising from the boundary, the Gaussian model accurately describes the statistics of the billiard eigenfunctions.

A Study on Within-Subject Factors for Visually Induced Motion Sickness by Using 8K Display

Visually induced self-motion perception (vection) is one of the phenomena related to human vision. It often emerges as a precursory symptom of motion sickness while viewing moving images. Employing a large number of subjects in a wide range of age groups and using a large-scale 8 K display, we investigated within-subject factors which can influence a sense of vection. We report some results of statistical analyses of vection-induced body sway which occurred when the subjects viewed rotating images on the display. Then we find that our fundamental study may provide useful information in order to set safety guidelines for large-scale ultra-high-definition displays such as 4K and 8K which are becoming popular in public use.

Effects of long-time 3d viewing on the eye function of accommodation and convergence

Recently we developed a device by combining a binocular autorefractometer and an eye mark recorder. Then, using the device together with images of very natural and high quality, we have carried out a sequence of experiments on simultaneous measurements of both accommodation and convergence while viewing virtual 3D objects. The results show that there is essentially no discrepancy in the dynamical behaviors of accommodation and convergence especially for young subjects and that they are hence very close to the case of natural viewing of real 3D objects. Following our previous experiments, we now investigate effects of long-time viewing of virtual 3D objects on the eye function of accommodation and convergence. We show that the synchronous dynamical behaviors of accommodation and convergence are definitely not a temporal effect but last for a long time.

Effect of weak hyperopia on stereoscopic vision

Convergence, accommodation and pupil diameter were measured simultaneously while subjects were watching 3D images. The subjects were middle-aged and had weak hyperopia. WAM-5500 and EMR-9 were combined to make an original apparatus for the measurements. It was confirmed that accommodation and pupil diameter changed synchronously with convergence. These findings suggest that with naked vision the pupil is constricted and the depth of field deepened, acting like a compensation system for weak accommodation power. This suggests that people in middle age can view 3D images more easily if positive (convex lens) correction is made.

Temporal Evolution in Potential Functions While Peripheral Viewing Video Clips with/without Backgrounds

In daily life, stereoscopic image technology, such as 3D TV and movies, has become used in various places. Images, not limited to stereoscopic images, may exhibit unfavorable biological effects depending on the viewing and physical conditions, age, and individual differences. In our previous study, an increase was indicated in the sway values that were observed while/after peripheral viewing a stereoscopic video clip. Backgrounds are considered to affect our balance function. We examine the effect of the exposure to stereoscopic video clips without the background on our equilibrium function paper, and fifteen healthy young males voluntarily participated in the present study. Their stabilograms were recorded during monocular vision or binocular parallax vision using semipermeable smart glasses, where the subjects maintained the Romberg posture in stabilometry. We also measured the body sway with the subjects’ eyes closed 0–3 min after the exposure to the video clips. We herein compare the temporal averaged potential functions to control the standing posture during the exposure to 2D/3D video clips with those after the exposure.

Age-dependence of work efficiency enhancement in information seeking by using see-through smart glasses

Very recently, wearable devices have become popular and recognized as useful tools to assist human activities. Especially, see-through smart glasses, which are featuring the augmented reality (AR) technology, can overlay a virtual image on the real view. One of the major functions of the device is to effectively direct attention to a certain location in the view and there let one read virtually-presented information in relation to the real world as is intended. Our primary research interest is age-dependence of work efficiency enhancement in information seeking with the help of AR by using see-through smart glasses. We report the result of our experimental study, adopting our originally developed Route Tracking Test (RTT) for information seeking. We also discuss a potential application to visual instructions for assembly work in school education.