• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.505-508
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• 2009

The super multi-view (SMV) display and the high-density directional (HDD) display were proposed as a natural 3D display that is free from the visual fatigue caused by the accommodation-vergence conflict and provides smooth motion parallax. The multi-projection system, the flat-panel system, and the time-multiplexing system are used to construct the HDD displays. The recent progress of the HDD 3D display is reviewed.

• ETRI Journal
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• v.40 no.3
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• pp.366-375
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• 2018

Recently, techniques involving head-mounted displays (HMDs) have attracted much attention from academia and industry owing to the increased demand for virtual reality and augmented reality applications. Because HMDs are positioned near to users' eyes, it is important to solve the accommodation-vergence conflict problem to prevent dizziness. Therefore, holography is considered ideal for implementing HMDs. However, within the Nyquist region, the accommodation effect is limited by the space-bandwidth-product of the signal, which is determined by the sampling number of spatial light modulators. In addition, information about the angular spectrum is duplicated over the Fourier domain, and it is necessary to filter out the redundancy. The size of the exit-pupil of the HMD is limited by the Nyquist sampling theory. We newly propose a holographic HMD with an expanded exit-pupil over the Nyquist region by using the time-multiplexing method, and the accommodation effect is enhanced. We realize time-multiplexing by synchronizing a high-speed digital micromirror device and a liquid-crystal shutter array. We also demonstrate the accommodation effect experimentally.

• Electronics and Telecommunications Trends
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• v.32 no.5
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• pp.65-73
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• 2017

A holography technique optically reconstructs a three-dimensional object in space to provide a natural sense of depth and volume to the observer, thereby providing an ultimate 3D image capable of solving the problem of "vergence-accommodation conflict" occurring in a conventional stereoscopic imaging system. In this paper, we present a technical framework for measuring the performance and evaluating the quality of a holographic display, which enables a quantitative measurement of the optical and physical properties that affect the performance and quality of a holographic display. In addition, we provide the trend regarding standardization related to holographic display measurements. Although this trend has barely started, research activities related to holographic display measurements and quality evaluations are expected to grow in the near future.

• Current Optics and Photonics
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• v.4 no.6
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• pp.524-529
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• 2020

We propose a depth-fused-type three-dimensional (3D) near-eye display implemented using a birefringent lens set that is made of calcite. By using a birefringent lens and image source (28.70 mm × 21.52 mm), which has different focal lengths according to the polarization state of the incident light, the proposed system can present depth-fused three-dimensional images at 4.6 degrees of field of view (FOV) within 1.6 Diopter (D) to 0.4 D, depending on the polarization distributed depth map. The proposed method can be applied to near-eye displays like head-mounted display systems, for a more natural 3D image without vergence-accommodation conflict.

• Current Optics and Photonics
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• v.7 no.6
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• pp.597-607
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• 2023

Volumetric 3D displays generate voxels to enable users to watch three-dimensional virtual objects from various angles, and they have a significant advantage over other types of 3D displays in terms of realism and the absence of vergence-accommodation conflict (VAC). By virtue of these advantages, various volumetric 3D display technologies incorporating novel approaches have been introduced competitively. As a result, the conventional classification criteria for volumetric 3D technology often fall short in categorizing these innovative methods. In this study, we present an improved classification framework capable of accommodating these new technologies. We expect that a new classification may offer some intuition to identify areas of technical deficiency and contribute to improving the technology.

• Journal of Korea Multimedia Society
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• v.19 no.9
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• pp.1723-1737
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• 2016

When watching 3D contents, people often experience various visual discomforts like tiredness, dryness, headaches, and dizziness. Previous researches on visual discomfort analyzed and concluded vergence-accommodation conflict, viewing distance, and brightness changes to be the causes of visual discomfort. Yet it is necessary to systematically analyze the visual discomfort due to the changes in object, background brightness and viewing distance. In this paper, we produce four videos that have four different background brightness and two different viewing distances to solve analyze the visual discomfort from watching 3D contents. We measure and analyze eye-blink and saccadic movement, saccadic latency, Nearest Point of Convergence (NPC), and participant survey for amore accurate result compared to previous researches. Our results show that the eye-blink rate and saccadic latency increase when the background is bright and viewing distance is close while the saccadic movement decreases in the same environment. However, NPC only changes when the background brightness changes. We confirm that the bright background and near viewing distance create greater visual discomfort and decrease depth perception abilities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1067-1073
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• 2021

Participants in the virtual environment will have an immersive and memorable perceived experience through interacting with virtual objects. Recently, commercial virtual reality technologies have released simple and cost-effective smartphone-based head-mounted displays (HMD) and high-quality wide field-of-view (FOV) HMDs. However, due to the vergence-accommodation conflict structure of HMD and the learned cognition mechanism in real, side effects such as dizziness and nausea remain challenging to overcome. This study focuses on consistent size perception among various cognitive difference factors, which are essential for interaction with virtual objects. We verified whether the visual angle, which affects the size perception of an object in real, is also the main factor in the virtual environment. Our experiments derived the relation between the visual angle and the environmental components, shadow, and grid, which help perceive a virtual object. As a result of the regression analysis, we presented that in the small FOV HMD environment, the visual angle affects size perception, and the relation between the shadow and the grid is statistically significant.

• Science of Emotion and Sensibility
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• v.19 no.1
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• pp.61-70
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• 2016

3D visual fatigue is known as one of the most important factors that interfere the commercial success of 3D contents. Vergence-accommodation conflict, which is known to occur when an observer watches an image containing binocular disparity presented on a 3D display, has been suggested as a major cause of 3D visual fatigue. This implies that any image incorporating binocular disparity might cause 3D visual fatigue. In order to reduce 3D visual fatigue, it would be necessary to consider indirect ways of reducing 3D visual fatigue as well as eliminating the direct causes of 3D visual fatigue. We have examined the effect of the variables that are expected to affect subjective 3D visual fatigue and these variables included the relative disparity contained in an image, viewing distance and viewing angle. We have also figured out the proper levels of the variables required to minimize 3D visual fatigue. The results indicate that observers began to report significant 3D visual fatigue when the crossed disparity contained in an image exceeded 7.22' and the vertical viewing angle was larger than 15 degree.