• Broadcasting and Media Magazine
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• v.24 no.2
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• pp.39-52
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• 2019

본 고에서는 라이트필드 혹은 디지털 홀로그램에 기반한 근안 디스플레이 기술에 대하여 알아본다. 헤드 마운티드 디스플레이로 불리기도 하는 근안 디스플레이는 사용자가 착용하는 안경 형태의 디스플레이 기기를 말하며, 가상현실 및 증강현실 응용의 핵심 기기 중 하나이다. 본 고에서는 라이트필드 및 디지털 홀로그램 기술이 근안 디스플레이에 적용될 경우 갖는 장점들을 살펴보고 관련 연구 동향을 소개한다.

• Review of Korea Contents Association
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• v.14 no.4
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• pp.14-16
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• 2016

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.549-552
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• 2022

본 논문에서는 가상현실에서 헤드 마운티드 디스플레이(Head mounted display, HMD) 사용자와 Non-HMD 사용자에게 사용자의 걷기, 뛰기, 절름발이 움직임을 몰입감 있게 표현하기 위한 새로운 가상현실(VR, Virtual Reality) 인터페이스를 제안한다. 가상현실에서는 몰입감을 높이기 위해 시각적 감각을 활용한 HMD와 사용자의 자세나 움직임을 추적하는 장비를 활용하지만, 일반적인 사용자들에게 HMD 보급은 많이 이루어져 있지 않으며, 비용적인 측면과 멀미로 인해 가상현실 콘텐츠에 몰입하기 어렵다. 본 논문에서는 효율적으로 몰입도를 높이고 비용적인 부담을 줄여주기 위해 아두이노를 활용한 새로운 보행 인터페이스 장치를 제안한다. 보행 인터페이스 장치는 사용자의 다리 가속도 정보를 기반으로 사용자의 상태 변화에 맞게 패턴을 설정하여 사용자의 걷기, 뛰기, 절름발이 움직임을 통해 사용자 캐릭터의 움직임을 제어하고 표현할 수 있는 새로운 결과를 보여준다.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.277-285
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• 2020

The purpose of this study was to evaluate the effects of wearing Head-Mounted Display (HMD) on the cervical range of motion (CROM), neck muscle thickness, and pain in healthy young adults. The HMD group(male=16, female=7) was asked to perform sitting comfortably in a backless chair with hands on their knees with the HMD was worn on their heads to watch the video for 30 minutes. The control group(male=15, female=8) was asked to sit in the same posture as the HMD group for 30 minutes. CROM, neck muscle thickness, and pressure pain threshold (PPT) of both the upper trapezius and levator scapulae were measured before and after intervention. CROM and PPT of the upper trapezius and levator scapulae in the HMD group were significantly decreased and the thickness of the muscles in the HMD group were significantly increased more than in the pre-test (p<.05). There was no significant difference in CROM, muscle thickness, and PPT in the control group. Wearing HMD for a long time can cause a decrease in CROM and PPT and an increase in muscle thickness, and there is a risk of developing musculoskeletal disorders in the neck and shoulder. Therefore, this study recommends maintaining the correct posture of the neck and shoulder and using HMD only for an appropriate time.

• 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.

• Korean Journal of Optics and Photonics
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• v.34 no.4
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• pp.157-169
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• 2023

Augmented reality (AR) using a head mounted display (HMD) is used in various fields such as military, medicine, manufacturing, gaming, and education. In this paper, we discuss the design and fabrication of the AR optical system, which is most essential for HMD. The AR optical system for HMD requires a wide transparent area in which the augmented image of the display and the real world can be viewed at the same time. To this end, an AR optical system was designed and manufactured by dividing it into three parts according to each characteristic. Also, the refractive index of the ultra-violet (UV) adhesive layer required to make the three optical systems into one complete AR optical system was considered from the design stage to minimize the optical path shift phenomenon when the input light source passes through the UV adhesive layer. In addition, when designing the AR optical system, two aspheric surfaces were used to compensate for off-axis aberration and to be suitable for mass production. Finally, for HMD mass production, an aspheric AR optical system with a thickness of 11 mm, a diagonal field of view of 40°, and a weight of 11.3 g was designed and manufactured.

• Korean Journal of Optics and Photonics
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• v.25 no.3
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• pp.125-130
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• 2014

Holographic optical elements (HOEs) provide systems of thin-film optics that could include a variety of functions and have many advantages as optical devices in various research fields. Research and developments based on the use of HOEs in the fields of communications and displays are in progress. This paper introduces the properties of HOEs and their applications in diffractive optical elements (DOEs), holographic projection screens, and head-mounted displays (HMDs). For widespread use of HOE technology in these various applications some challenges need to be solved, as discussed in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.782-788
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• 2018

This paper proposes a novel method for the omnidirectional camera-based image rendering synchronization system using head mounted display. There are two main processes in the proposed system. The first one is rendering 360-degree images which are remotely photographed to head mounted display. This method is based on transmission control protocol/internet protocol(TCP/IP), and the sequential images are rapidly captured and transmitted to the server using TCP/IP protocol with the byte array data format. Then, the server collects the byte array data, and make them into images. Finally, the observer can see them while wearing head mounted display. The second process is displaying the specific region by detecting the user's head rotation. After extracting the user's head Euler angles from head mounted display's inertial measurement units sensor, the proposed system display the region based on these angles. In the experimental results, rendering the original image at the same resolution in a given network environment causes loss of frame rate, and rendering at the same frame rate results in loss of resolution. Therefore, it is necessary to select optimal parameters considering environmental requirements.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.889-891
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• 2018

가상현실 (Virtual Reality, VR) 컨텐츠가 다양해지면서 사용자들의 관심도 높아지고 있다. 초기 VR 컨텐츠는 헤드 마운티드 디스플레이 (Head Mounted Display, HMD)와 컨트롤러만 사용한다. 사용자의 요구가 높아지면서 현실적인 컨텐츠 구현을 위해서 사용자의 신체 움직임으로 제어하는 풀 바디 트래킹(Full Body Tracking) 기술이 도입되고 있다. 머리에 착용하는 HMD와 양손으로 제어하는 두 개의 컨트롤러 뿐만 아니라 모션캡쳐장비, 트래커 장비를 사용자의 다양한 위치에 착용시켜, 세밀한 움직임 트래킹이 가능해졌다. 본 연구에서 서브 모션 기반의 움직임 추적 방법과 이를 기반한 서브모션 시스템을 제안한다. 서브모션 시스템은 VR 컨텐츠에 사용되는 사용하는 센서 위치를 VR캐릭터의 대응되는 위치에 출력하는 방식이 아닌, 사용자의 움직임에 따라 다양한 센서 위치 변화를 인식하고, 이를 기반으로 VR에서 사전에 지정된 모션을 인식 및 출력한다. 사용자의 움직임을 세분화하여 각각의 연속된 서브모션들로 인식하고, 각각의 서브 모션에서 연속적으로 인식 가능한 서브 모션을 분기를 통해 정의하고 인식함으로써 다양하고 자유도 높은 모션 처리가 가능하다. 선행 기술들의 문제점인 고정된 데미지 방식 및 부자연스러운 모션을 해결하고 사용자에게 실제와 같은 동작을 취하도록 유도하여 몰입감등을 부여할 수 있다. 서브 모션들을 자동적으로 생성하는 시스템을 통해 풀 바디 트래킹 VR 컨텐츠에 적용 가능한 엔진을 연구 및 개발하여 해당 산업의 발전에 이바지하고자 한다.

• Journal of the Korea Computer Graphics Society
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• v.27 no.3
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• pp.43-53
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• 2021

This paper presents an interactive wind system that generates artificial winds in a virtual reality (VR) environment according to online user inputs from a steering wheel and an acceleration pedal. Our system is composed of a head-mounted display (HMD) and three electric fans to make the user sense touch from the winds blowing from three different directions in a racing car VR application. To evaluate the effectiveness of the winds for reducing VR cybersickness, we employ the simulator sickness questionnaire (SSQ), which is one of the most common measures for cybersickness. We conducted experiments on 13 subjects for the racing car contents first with the winds and then without them or vice versa. Our results showed that the VR contents with the artificial winds clearly reduce cybersickness while providing a positive user experience.