• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.113-123
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• 2022

Ray tracing-based rendering creates by far more realistic images than the traditional rasterization-based rendering. However, it is still burdensome when implemented for a Head-Mounted Display (HMD) system that demands a wide field of view and a high display refresh rate. Furthermore, for presenting high-quality images on the HMD screen, a sufficient number of ray sampling should be carried out per pixel to alleviate visually annoying spatial and temporal aliases. In this paper, we extend the recent selective foveated ray tracing technique by Kim et al. [1], and propose an improved real-time rendering technique that realizes the rendering effect of the classic Whitted-style ray tracing on the HMD system. In particular, by combining the ray tracing hardware-based acceleration technique and time-constrained rendering scheme, we show that fast HMD ray tracing is possible that is well suited to human visual systems.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.4
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• pp.31-40
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• 2016

Recently, technology of Virtual Reality(VR) based on HMD among various kinds of VR implemented products has received widespread attention. Major IT-related companies around the world participated in VR HMD research and development. Therefore, the possibility of the spread of VR HMD has been highly praised. Demands of VR HMD products using Smart Phone has been especially increased so that it is required to create a high quality of VR contents. The purpose of study in this paper is to apply the depth value of stereoscopic to VR HMD. To implement it, we analyzed VR HMD optical system and converted an experimental image to virtual depth caused by binocular disparity based on the result of calculating NPP(Native Pixel Parallax). We produced the image of stereoscopic applied with the value converted and applied to VR HMD. This study is expected to be utilized as a VR content creation field of quantitative data.

• Korean Journal of Optics and Photonics
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• v.29 no.1
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• pp.19-27
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• 2018

A change in object distance would generally change the magnification of an optical system. In this paper, we have proposed and designed a double-Gauss optical system with a fixed magnification and image surface regardless of any change in object distance, according to moving the lens groups a little bit to the front and rear of the stop, independently parallel to the direction of the optical axis. By maintaining a constant size of image formation in spite of various object-distance changes in a projection system such as a head-up display (HUD) or head-mounted display (HMD), we can prevent the field of view from changing while focusing in an HUD or HMD. Also, to check precisely the state of the wiring that connects semiconductor chips and IC circuit boards, we can keep the magnification of the optical system constant, even when the object distance changes due to vertical movement along the optical axis of a testing device. Additionally, if we use this double-Gauss optical system as a vision system in the testing process of lots of electronic boards in a manufacturing system, since we can systematically eliminate additional image processing for visual enhancement of image quality, we can dramatically reduce the testing time for a fast test process. Also, the Gaussian bracket method was used to find the moving distance of each group, to achieve the desired specifications and fix magnification and image surface simultaneously. After the initial design, the optimization of the optical system was performed using the Synopsys optical design software.

• Journal of the HCI Society of Korea
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• v.4 no.2
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• pp.9-16
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• 2009

3D stereo display systems gain more interests recently. Multiple-view autostereoscopic display system enables observers to watch stereo image from multiple viewpoints not wearing specific devices such as shutter glasses or HMD. Therefore, the Multiple-view autostereoscopic display is being spotlighted in the field of virtual reality, mobile, 3D TV and so on. However, one of the critical disadvantages of the system is that observer can enjoy the system only in a small designated area where the system is designed to work properly. This research provides an effective way of GPU based rendering technique to present seamless 3D stereo experiences from an arbitrary observer's view position.

• Journal of Korea Multimedia Society
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• v.22 no.1
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• pp.110-116
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• 2019

Virtual reality (VR) sickness can have an influential effect on the viewing quality of VR 3D contents. Particularly, watching the 3D contents on a head-mounted display (HMD) could cause some severe level of visual discomfort. Despite the importance of assessing the VR sickness, most of the recent studies have focused on unveiling the reason of inducing VR sickness. In this paper, we subjectively measure the level of VR sickness induced in the viewing of omnidirectional 3D graphics contents in HMD environment. Apart from that, we propose an objective assessment model that estimates the level of induced VR sickness by calculating the difference between head movement velocity and global camera motion velocity.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.248-251
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• 2015

High injury and fatality rates remain a serious problem in the construction industry. Many construction injuries and fatalities can be prevented if workers can recognize potential hazards and take actions in time. Many efforts have been devoted in improving workers' ability of hazard recognition through various safety training and education methods. However, a reliable approach for evaluating this ability is missing. Previous studies in the field of human behavior and phycology indicate that the visual focus of attention (VFOA) is a good indicator of worker's actual focus. Towards this direction, this study introduces an automated approach for estimating the VFOA of equipment operators using a head orientation-based VFOA estimation method. The proposed method is validated in a virtual reality scenario using an immersive head mounted display. Results show that the proposed method can effectively estimate the VFOA of test subjects in different test scenarios. The findings in this study broaden the knowledge of detecting the visual focus and distraction of construction workers, and envision the future work in improving work's ability of hazard recognition.

• IE interfaces
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• v.16 no.2
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• pp.149-155
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• 2003

The focus of this study is to investigate how personal display systems - a VDU (Visual Display Unit) and an HMD (Head Mounted Display) physiologically affect the body in virtual environments, and to evaluate differential effects of using the VDU and the HMD on physiological responses to mental stressful tasks (virtual reality flight simulation). As physiological variables, autonomic measures (heart rate, blood pressure), immune cells (leukocyte, neutrophil, lymphocyte), and hormones (catecholamine) were measured before and after experiments. Physiological data were measured in order to compare a level of mental stress on the VDU and the HMD. Increments in blood pressure (systolic (p<0.05), diastolic (p<0.1)), norepinephrin (catecholamine) (p<0.005), and neutrophils (p<0.2) of the group using the HMD showed a significant difference with the group using the VDU. Although, the heart rate was not statistically significant between two environments, differences of them quietly increased on the HMD more than on the VDU.

• Electronics and Telecommunications Trends
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• v.31 no.4
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• pp.13-22
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• 2016

다수의 미디어와 기술 시장 보고서가 2016년을 가상현실(Virtual Reality: VR) 기술이 대중화되는 원년으로 전망하고 있다. 착용형 디스플레이는 컴퓨터로 시뮬레이션되는 가상의 콘텐츠 세계와 현실의 사용자를 연결하는 대표적인 VR 인터페이스 장치이다. 일정 수준 이상의 사용성을 제시하는 데에 필요한 기술의 진입 장벽이 낮아지면서 다양한 소비자 제품들의 시장 출시가 진행 중이고, 주요 업체들은 킬러 콘텐츠 발굴과 함께 새로운 산업 생태계 구축에 역량을 집중하고 있다. 선도적인 연구그룹들은 차세대 가상/증강현실(VR/AR) 인터페이스의 구현 목표를 가볍고 휴대성이 우수한 안경형 디스플레이에 두고 있으며, 모니터 및 키보드와 마우스를 벗어난 다양한 입출력 기술을 개발하고 있다. 본고에서는 VR 시장의 중심이 되고있는 완전몰입형 디스플레이(Head Mounted Display: HMD) 현황을 정리하고, 향후 AR 시장으로의 확대에 기반이되는 안경형 디스플레이(Eye Glasses-type Display: EGD) 기술의 연구개발 동향을 정리한다.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.116-119
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• 2019

User interface/experience and realistic game manipulation play an important role in virtual reality first-person-shooting game. This paper presents an intuitive hands-free interface of gaming interaction scheme for FPS based on user's gesture recognition and VR controller. We focus on conventional interface of VR FPS interaction, and design the player interaction wearing head mounted display with two motion controllers; leap motion to handle low-level physics interaction and VIVE tracker to control movement of the player joints in the VR world. The FPS prototype system shows that the design interface helps to enjoy playing immersive FPS and gives players a new gaming experience.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.37-43
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• 2006