Takashi Shibata

• PhD
• Professor at Tokai University

Recent increased usage of stereo displays has been accompanied by public concern about potential adverse effects associated with prolonged viewing of stereo imagery. There are numerous potential sources of adverse effects, but we focused on how vergence-accommodation conflicts in stereo displays affect visual discomfort and fatigue. In one experime...

As 3D technology spreads, 3D imagery is being viewed in more diverse situations. Already, televisions and mobile devices are able to present 3D images, in addition to the cinema. Of these, mobile devices have the unique characteristic of requiring users to view images at close range. The authors conduct an experiment to examine the relationship bet...

We conducted experimental classes in an elementary school to examine how the advantages of using stereoscopic 3D images could be applied in education. More specifically, we selected a unit of the Tumulus period in Japan for sixth-graders as the source of our 3D educational materials. This unit represents part of the coursework for the topic of Japa...

Purpose: To determine optimal display positions during heads-up surgery (HUS) to minimize crosstalk. Methods: Three three-dimensional (3D) displays were analyzed to evaluate the relationship between display position and amount of crosstalk. First, the 3D displays were calibrated to show a completely white image in the right eye and completely bl...

Along with the education informatization, use of tablet computers in school classrooms is gaining considerable popularity as a means of improving educational quality. Accordingly, investigating the tablet computer usage among students from an ergonomics viewpoint is important because the usage environment in schools differs from that in daily life....

In the present paper, I discuss several attempts of conducting experimental classes in schools to evaluate the educational effects and advantages of using stereoscopic 3D images and virtual reality (VR) techniques in schools. In comparison with 2D educational material, 3D material can help students focus on specific parts in images as well as to un...

Heads‐up surgery is an operation performed while viewing the surgical field on a 3D display instead of using the eyepiece of the microscope. Clinical trials of ophthalmic surgery revealed that this technique shortened the operation time over time. However, some issues were also identified.

The advantages of stereoscopic 3D images in education were evaluated in an elementary schools' experimental class. The results from the worksheets filled out by students revealed that educational 3D material could help students focus on details and understand three-dimensional spaces or concavo-convex shapes.

Rapid advances in computer and display technologies have made it possible to present high quality virtual reality (VR) environment. To use such virtual environments effectively, research should be performed into how users perceive and react to virtual environment in view of particular human factors. We created a VR simulation of sea fish for scienc...

The authors conducted an experiment that examined the relationship between visual comfort and an individual observer's near phoria in terms of the length of time spent viewing 3D content on a mobile device. Two experimental parameters were used: the position of the stereo video images (in front of the screen and behind the screen) and the time for...

Prolonged use of conventional stereo displays causes viewer discomfort and fatigue because of the vergence-accommodation conflict. We used a novel volumetric display to examine how viewing distance, the sign of the vergence-accommodation conflict, and the temporal properties of the conflict affect discomfort and fatigue. In the first experiment, we...

We conducted an experiment that examined how visual discomfort arises while viewing autostereoscopic displays in a practical viewing situation. Visual discomfort was evaluated by measuring subjective symptoms and accommodative step response before and after viewing displayed material. Subjective discomfort measurements showed that viewing autostere...

Stereo 3D (S3D) is becoming increasingly commonplace in cinema, television, gaming, and elsewhere. S3D viewing is known to cause visual discomfort and fatigue. Conflicts between vergence and accommodation are one source of such symptoms. We measured the combinations of vergence and accommodative stimuli that yield comfortable S3D viewing. We also e...

Prolonged use of conventional stereo displays causes viewer discomfort and fatigue because of the vergence-accommodation conflict. We used a novel volumetric display to examine how viewing distance and the sign of the vergence-accommodation conflict affect discomfort and fatigue. In the first experiment, we presented a fixed conflict at short, medi...

Since 3D display methods and viewing environments vary widely, high-quality content is expected to become multi-purpose. Meanwhile, there is increasing interest in the bio-medical effects of various types of image content and there are moves toward international standardization, so safety and comfort need to be considered in 3D content production....

Monocular head-mounted displays (HMDs) will be a major tool for ubiquitous computing. However, monocular HMD visibility causes a decrease in the light received from the environment. Fluctuating light from the environment strongly affects the visibility of images presented on the monocular HMD. In the present study, we have studied a method for cont...

Stereoscopic displays can produce perceptual distortions, performance decrements, and fatigue/discomfort because of conflicts between the presented binocular disparities and focus cues (blur and accommodation). We have developed a display that circumvents this problem. It uses a fast switchable lens synchronized to the display such that focus cues...

This paper describes the making of stereoscopic 3-D movies utilizing the Metaverse. The authors focused on machinima, which is a way to make movies using PCs and video games. A tool for making stereoscopic 3-D movies in Second Life is proposed. The tool also enables running experiments with different ways of stereo shooting. The purpose of this stu...

Monocular head-mounted displays (HMD) are expected as a core device for ubiquitous computing. However, monocular HMD can decrease the visibility by environment light. High luminance environment light makes high contrast between the environment and images presented by monocular HMD. This situation causes perceptional lost of the images. In this stud...

High-quality stereoscopic image content must be viewable in a variety of visual environments, from 3-D theaters to 3-D mobile devices. Stereoscopic effects, however, are affected by screen size, viewing distance, and other parameters. In this study, the authors focus on the stereoscopic image quality experience of viewing 3-D content on a mobile de...

Stereoscopic filming is roughly divided into two types: toed-in and parallel camera configurations. Both types have disadvantages: toed-in cameras cause keystone distortions, and parallel cameras cause image loss by shifting. In addition, it is difficult for inexperienced creators to understand the optimal camera settings and post-processing proced...

A floating-image display produces 3-D effects using a lens system that makes an image appear to float in the air. The authors examine the effects on depth perception and asthenopia of viewing a floating image that continuously changes in size. The results of the experiments suggest that viewers perceive the floating image to be moving back and fort...

A field-sequential colour projection system can display colour images using a single panel. Such a system, however, produces characteristic trichromatic separation, or “colour breakup”. Colour breakup is the perceived splitting of the white portions of an image into its red, green, and blue components when the image is projected with the colour seq...

Digital 3D cinema has recently become popular and a number of high-quality 3D films have been produced. However, in contrast with advances in D display technology, it has been pointed out that there is a lack of suitable 3D content and content creators. Since D display methods and viewing environments vary widely, there is expectation that high-qua...

本研究では, 光学補正により観察者の調節を適切に作用させられる立体ディスプレイを用いて, 立体映像を観察することによる眼精疲労の回復効果を検討した. 実験1では, 立体映像の観察前後に視力と眼精疲労の自覚症状を測定することで, 回復効果の程度を検討した. そして, 実験2では, 一日中VDT作業を行っている事務職員を被験者として, 朝の測定値および平面映像観察と比較することで回復効果を検討した. また, 被験者の視覚状態に合わせて徐々に遠方視させることを目的とした刺激呈示のフィードバック機能を用いて, 調節の緊張緩和を促した. 実験の結果から, 調節が適切に作用する立体映像は, 平面映像と比較して, 眼精疲労の回復効果が高いことが示された. 本研究で得られた眼精疲労の回復効果は, 一過性の反...

A field-sequential color projection system displays color images using a single panel and a color filter wheel. The wheel spins very rapidly, and creates a sequence of red, green, blue, and white images that combine to create a single full-color image. Although the use of a single panel can reduce both projector size and costs, the field-sequential...

Monocular head-mounted displays (HMDs) can be used with wearable computers. However, such displays can cause binocular rivalry, a phenomenon in which the left and right images alternate, and is unstable. Binocular rivalry, when using HMD, causes the image of the environment to alternate with the HMD image, or even the total loss of perception of th...

This paper presents ergonomic approaches to editing and evaluating content for 3D displays. Two systems, a nonlinear editing system and an evaluation system, were developed to improve viewing safety and comfort for 3D content observ ers and provide better usability for the creators from the viewpoint of ergonomics.

A field-sequential color projection system can display color images using a single panel. However a characteristic trichromatic separation, or ‘color breakup’ occurs. The viewing of images in which color breakup occurs may cause visual fatigue and mental stress. Moreover, it is expected that the state of viewing is different. In this study, the aut...

Introduction: An increasing number of surgical procedures are performed in a microsurgical and minimally-invasive fashion. However, the performance of surgery, its possibilities and limitations become difficult to teach. Stereoscopic video has evolved from a complex production process and expensive hardware towards rapid editing of video streams wi...

This paper describes the trial development of an ergonomic evaluation system for stereoscopic video production. The purpose of the system is to quantify the parallax distribution of stereoscopic images and evaluate their viewing safety and comfort. The authors processed the images to extract the optical flow between the right and left images. The r...

A common cause of asthenopia is viewing objects from a short distance, as is the case when working at a VDT (Visual Display Terminal). In general, recovery from asthenopia, especially accommodative asthenopia, is aided by looking into the distance. The authors have developed a stereoscopic 3-D display with dynamic optical correction that may reduce...

The experimental production of an ergonomic evaluation system for stereoscopic 3-D images is described. The purpose of the system is to quantify the depth sensation of 3-D images and to evaluate them. Image processing was applied to compute the optical flow between right and left videos. The functionality of the system was examined by referring to...

We developed a prototype system to reduce asthenopia by using stereoscopic 3-D images that moved in depth direction, and evaluated the effects of the system. Accommodative step response time, profiles of mood states and refractions were measured as indexes for examining the subject's visual fatigue. In young subjects, the accommodative relaxation t...

This paper describes a method for reducing the discrepancy between accommodation and convergence when viewing stereoscopic 3-D images. The method uses a newly developed stereo-scopic 3-D display system with a telecentric optical system and a mobile LCD. The examination of a mono-focal lens showed that a correction lens having the appropriate refrac...

The purpose of this study was to consider a practical application of a newly developed stereoscopic 3-D display that solves the problem of discrepancy between accommodation and convergence. The display uses dynamic optical correction to reduce the discrepancy, and can present images as if they are actually remote objects. The authors thought the di...

Stereoscopic video teaching can facilitate understanding for current minimally-invasive operative techniques. This project was created to set up a digital stereoscopic teaching environment for training of ENT residents and medical students. We recorded three ENT operative procedures (tympanoplasty, paranasal sinus operation and laser chordectomy) a...

Pachinko is a pinball-like game peculiar to Japan, and is one of the most common pastimes around the country. Recently, with the videogame market contracting, various multimedia technologies have been introduced into Pachinko machines. The authors have developed a Pachinko machine incorporating an autostereoscopic 3D display, and evaluated its effe...

Stereoscopic video teaching can facilitate understanding for current minimally-invasive operative techniques. This project was created to set up a digital stereoscopic teaching environment for training of ENT residents and medical students. We recorded three ENT operative procedures (tympanoplasty, paranasal sinus operation and laser chordectomy) a...

This paper describes an examination of a stereoscopic 3-D display system using a correction lens. The purpose of the system is to reduce the accommodation and convergence difference during viewing stereoscopic 3-D images by using simple technique. This correction lens is a mono-focal lens, and added to the polarized filter glasses. In this study, t...

We developed software for the non-linear editing of stereoscopic 3-D movies. This software has functions unique to stereoscopic 3-D movies and works on a personal computer. Editing is much simpler with this software than it is with conventional systems that require four synchronized video tape recorders. At the same time, the software makes possibl...

We describe the development and evaluation of an electro- optical 3D adapter for recording stereoscopic 3D images with a standard video camcorder. The adapter uses a combination of liquid crystal shutters and a half prism to record right and left images in each field of an NTSC signal. The purpose of this study was to develop a simple and usable 3D...

This paper describes the development of software for non- linear editing of stereoscopic 3-D movies. The purpose of the software is to simplify the creation of stereoscopic 3-D movies as well as reduce production costs. The software has the following functions: 1) Separate a field-sequential movie file into right and left movie files. 2) Display ri...

This chapter describes head mounted displays (HMDs) from the viewpoint of the human factors. Because it has two separate display systems, HMDs are especially effective in displaying stereoscopic images. To develop better stereoscopic three-dimensional display technologies, it is important to investigate visual functions such as accommodation and co...

This paper describes a production of stereoscopic 3D movies of a Spanish monastery for a digital archive. The authors have previously produced and presented an experimental virtual museum of Japanese Buddhist art in 1995. The purpose of this study was to produce a parallel with it, and to examine a simple method for the production.