• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.772-774
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• 2008

A navigation system for virtual environments using low-quality HMD(head mounted display)must quantize images when the system presents true-color image with restricted number of colors. Such navigation system quantizes an image by using fixed palette. If the system represents an image by using a variable palette which is made considering a region around the viewpoint then user can perceive a virtual environments more vividly because human visual system is sensitive to the colors variation in the region around the viewpoint. In this paper we propose a color quantization algorithm that quantize a region around the viewpoint more finely than other regions at each variation of viewpoint for virtual environments navigation system and compose virtual environments navigation system using proposed algorithm. The system quantizes an image at each variation of viewpoint and shows a quantized image to user through HMD. We tested user preferences for our proposed system and the results show that users preferred our system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.423-425
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• 2019

Users may experience a sub-type of motion sickness, called cybersickness, when interacting with virtual reality (VR) applications in the state of wearing head mounted display (HMD) devices. Although the root cause of cybersickness is still unclear, it is believed to result from a sensory mismatch between visual and vestibular systems. However, there is a lack of studies developing data collection and analysis systems to measure cybersickness. In this paper, therefore, a system is designed that collects electroencephalography (EEG) and physiological data from a user wearing a VR HMD device through an internet of things (IoT) platform and decides whether a user experiences a symptom of cybersickness, namely dizziness, or not by using a decision threshold. Experimental results showed that the proposed system achieved about 92% accuracy of a dizziness detection when considering 14 participants.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2124-2127
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• 2003

This paper suggests user interface method with wearable computer by means of detecting gaze under HMD, head mounted display, environment. System is derived as follows; firstly, calibrate a camera in HMD, which determines geometrical relationship between monitor and captured image. Second, detect the center of pupil using ellipse fitting algorithm and represent a gazing position on the computer screen. If user blinks or stares at a certain position for a while, message is sent to wearable computer. Experimental results show ellipse fitting is robust against glint effects, and detecting error was 6.5％, and 4.25％ in vertical and horizontal direction, respectively.

• The Optical Journal
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• s.128
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• pp.38-41
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• 2010

HMD(Head mounted Display)는 보안경이나 헬멧 형태로 눈앞의 지근거리에 초점이 형성된 가상스크린을 보는 안경형 모니터 장치로서 예전에는 군사용 시뮬레이션이나 가상현실(VR-Virtual Reality)을 실현하기 위해 개발되었으며, 양쪽 눈의 근접한 유치에 설치된 1인치 이하의 LCD, OLED, MEMS panel 등 마이크로 디스플레이에서 발생되는 이미지를 광학시스템을 통해 확대하여 대형 가상화면을 형성한다. IT 산업의 비약적인 발전에 힘입어 휴대용 동영상 및 모바일 정보검색, 3D의 시대가 대두됨에 따라 휴대폰이나 PMP의 작은 화면으로는 만족하지 못하는 소비자의 수요에 적합한 개인 휴대용 모니터 장치로, 3D를 구현하는 안경형 모니터로서 향후 크게 형성될 모바일 산업의 핵심제품이 될 전망이다.

• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.67-73
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• 2022

In a head-mounted display (HMD) for virtual-reality applications, a narrow viewing angle is preferred to the usual, wide viewing angle because the HMD is positioned close in front of the user's eyes, and the display position is fixed. In this paper, we propose a new back-light unit (BLU) for implementing a narrow viewing angle, which is suitable for a HMD. By optimizing the scattering patterns in the light-guide-plate and inverse-prism structures, the viewing angle and correlations between structural parameters in the BLU components are analyzed with ray-tracing simulations. As a result, a double-angle inverse-prism structure incorporating the scattering patterns of a light-guide plate is chosen, which results in a 14% increase in center luminance, a 16% decrease in the vertical viewing angle, and a light efficiency of up to 70%, compared to a conventional BLU. Thus, the new BLU system is expected to be applied in a high-efficiency liquid crystal display.

• Information and Communications Magazine
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• v.32 no.5
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• pp.73-86
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• 2015

본고에서는 먼저 서비스 측면에서 사용자 중심인 모바일인터넷과 기기 간 통신인 사물인터넷 서비스, 단말 측면에서 안경단말기, HMD(Head Mounted Display), 드론, 스마트센서, Connected Car가 어떻게 5G 통신의 견인차 역할을 하는 지 알아보고, 5G서비스와 단말을 수용하는 코어와 무선액세스 네트워크 구조 및 중요 기술에 대해 설명한다. 또한, 5G 주파수 소요량 분석 및 선정을 위한 ITU-R 동향에 대해서도 간략히 알아본다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.89-90
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• 2008

본 논문은 네트워크를 통해서 이동로봇을 원격제어하기 위해 필요한 비전 시스템에서 HMD(Head Mounted Display)의 방향각 측정 알고리즘에 관한 연구이다. 우선 이 이동로봇 원격제어 시스템은 AP와 무선랜을 이용하여 독립 무선 네트워크를 구축하였고 이동로봇의 주변 환경을 레이저 센서와 스테레오 카메라를 이용하여 사용자에게 정보를 전송한다. 스테레오 카메라를 통해 전송된 영상 정보는 HMD를 통하여 볼 수 있다. 실시간으로 영상 카메라에 의해 측정 된 HMD의 회전 각도는 pen-tilt에 전송되어 HMD가 회전한 만큼 pen-tilt도 회전하여 이동로봇의 주변 환경 영상정보를 얻을 수 있는 알고리즘을 제안하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.701-702
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• 2022

최근 메타버스는 초대형 소셜미디어회사인 페이스북의 사명과 비전 변경으로 인해 그 어느 때보다 트랜디한 키워드로 부상되고 있다. 초기 메타버스는 지금의 가상현실(Virtual Reality)와 거의 동일한 개념으로 사용되었으나, 2007년 ASF이후 AR, VR, 미러월드, Lifelogging과 같이 다양한 영역을 통한 새로운 세계의 도출이라는 확장을 통해 그 활용 가능성이 무궁무진해지고 있다. 한편, 메타버스의 영역 확장에도 불구하고 HMD는 메타버스의 중요한 하드웨어라는 인식이 더 견고해지고 있는데, 그동안 고가였던 HMD가 2020년 보급형HMD의 등장으로 본격적인 판매량 증가를 보이고 있다. 본 연구는 메타버스의 중요 하드웨어 중 하나인 HMD(Head-Mounted Display)의 보급 정도를 기반으로 메타버스의 대중화 정도와 근미래에 대해 알아보고자 한다.

• PNF and Movement
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• v.18 no.2
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• pp.265-273
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• 2020

Purpose: The purpose of the study was to investigate the effects of HMD (head mounted display)-based virtual reality balance training on static balance in young adults, and whether appropriate balance training can help healthy adults to improve balance ability in daily living. Methods: The study subjects were 14 healthy adults. Subjects received 20 minutes of HMD-based virtual reality balance training 3 times per week for 4 weeks. Static balance was measured before, during, and after training and after one month. Static balance was measured in a total of 8 conditions, and the results were classified as visual (F1), somatosensory (F5-6), vestibular (F2-4), and central nervous system (F7-8). Results: The test results showed no significant difference in pre-training, post-training, and follow-up results under all conditions at Fourier index F1, F5-6, and F7-8 frequencies. For the F2-4 frequency, there was a significant difference before and after training under NC (neutral head position, eyes closed, firm surface) and PC (neutral head position, eyes closed, elastic surface) conditions. The NC condition returned a significant decrease of F2-4 frequency in post-training testing as compared to pre-training, and the PC condition showed a significant decrease of F2-4 frequency between the pre-training and mid-training tests, and between the pre-training and post-training tests. Conclusion: These results indicate that HMD-based balance training can improve balance ability, even in normal adults, and seems especially effective for vestibular function training.

• 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.