• Current Optics and Photonics
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• 제4권6호
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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.

• ETRI Journal
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• 제45권6호
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• pp.1046-1055
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• 2023

We introduce a display for virtual-reality (VR) fire training. Firefighters prefer to wear and operate a real breathing apparatus while experiencing full visual immersion in a VR fire space. Thus, we used a thin head-mounted display (HMD) with a light field and folded optical system, aiming to both minimize the volume for integration in front of the face into a breathing apparatus and maintain adequate visibility, including a wide viewing angle and resolution similar to that of commercial displays. We developed the optical system testing modules and prototypes of the integrated breathing apparatus. Through iterative testing, the thickness of the output optical module in front of the eyes was reduced from 50 mm to 60 mm to less than 20 mm while maintaining a viewing angle of 103°. In addition, the resolution and image quality degradation of the light field in the display was mitigated. Hence, we obtained a display with a structure consistent with the needs of firefighters in the field. In future work, we will conduct user evaluation regarding fire scene reproducibility by combining immersive VR fire training and real firefighting equipment.

• 방송공학회논문지
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• 제21권1호
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• pp.43-50
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• 2016

이 논문에서는 스마트폰을 사용한 비디오 투과식 증강현실에서 왜곡 보정과 시야각 조정을 다룬다. 삼성 기어 VR이나 구글의 카드보드와 같은 스마트폰을 사용한 HMD(Head Mounted Display)에서는 일반적으로 렌즈로 인해서 영상이 왜곡되어 렌더링이 된다. 특히나 스마트폰을 사용한 증강현실에서는 스마트폰의 카메라와 HMD의 렌즈로 인해서 발생하는 왜곡이 합해져서 보다 복잡한 형태의 왜곡이 발생하게 된다. 이러한 왜곡은 사용자에게 시각적인 인지나 인식 기능에 부조화를 야기하게 된다. 유리와 같은 투명 디스플레이를 궁극적인 형태의 HMD라고 생각하면 최대한 이런 왜곡을 없애서 투명한 것과 같은 효과를 주어야 한다. 이 논문에서는 스마트폰 기반 비디오 투과식 증강현실 방식에서 왜곡을 보정하고 시야각을 조정하여 투명에 가까운 효과를 주는 방법을 제시한다. 논문에서 왜곡 보정 및 시야각 조정 모듈을 개발하고 이에 대한 성능을 측정하였다.

• 농업생명과학연구
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• 제51권1호
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• pp.205-212
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• 2017

경운기 시뮬레이터 운전자가 가상환경에서 교육에 몰입할 수 있도록 현실세계에 가상 물체를 겹쳐 보여주는 증강 현실 기술을 구현하였다. 3D 카메라 입력 장치로부터 초당 30 frame 이상 속도로 경운기 모의 운전 장치의 영상을 획득한다. 획득된 현실 영상을 크로마키 처리하여 가상 현실과 결합하였다. RGB 영상의 HSI 변환 실험결과 색상 최대값 0.52, 최소값 0.153, 채도 최대값 0.57, 최소값 0.16, 명도 최대값 1, 최소값 0.12이 크로마키 처리를 위해 최적값이었다. 본 연구에서는 키패드를 이용하여 크로마키 처리된 현실 영상의 위치를 전 후 상 하 좌 우를 버튼으로 조정하여 초기 결합위치를 조정할 수 있고 최종 조정된 값은 저장하여 유지 관리되도록 하였다. 이를 토대로 초당 30프레임 이상의 속도로 가상현실과 크로마키 처리 영상을 결합한 증강현실 구현이 가능함을 보였다.

• PNF and Movement
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• 제18권2호
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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.

• 대한간호학회지
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• 제51권4호
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• pp.465-477
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• 2021

Purpose: This study aimed to evaluate the effects of head monted display based home-visits virtual reality simulation (HVRS) program developed for undergraduate nursing students. Methods: A nonequivalent control group with a non-synchronized design was utilized and 84 participants (experimental group, 44; control group, 40) were recruited from August 31, 2020 to November 8, 2020 in Gwangju metropolitan city. The HVRS program consisted of scenarios of three nursing cases, hypertension, diabetes mellitus, and stroke. Data were analyzed SPSS version 25.0 for Windows. Results: At the completion of HVRS, significant differences were found between groups in knowledge of home-visits (t = 4.73, p < .001), self-confidence (t = 6.63, p < .001), self-efficacy (t = 3.13, p = .002), and clinical competency (t = 4.13, p < .001). No significant difference was shown between groups in nursing knowledge about strokes, a subcategory of knowledge pertaining to home visits. Conclusion: The HVRS program developed for undergraduate nursing students is effective in improving knowledge of home-visits, self-confidence, self-efficacy, and clinical competency for nursing students.

• 한국광학회지
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• 제34권4호
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• pp.157-169
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• 2023

헤드 마운티드 디스플레이(head mounted display, HMD)를 이용한 증강 현실(augmented reality, AR)은 군사, 의료, 제조, 게임 및 교육 등 다양한 분야에서 활용되고 있다. 본 논문에서는 HMD에 가장 필수적인 AR 광학계의 설계 및 제작에 대해 논의한다. HMD용 AR 광학계는 디스플레이의 증강 영상과 현실 세계를 동시에 볼 수 있는 넓은 투명 영역이 필요하다. 이를 위해, AR 광학계를 각각의 특성에 따라 세 부분으로 나누어 설계 및 제작하였다. 그리고 3개의 광학계를 하나의 완전한 AR 광학계로 만들기 위해 필요한 ultra-violet (UV) 접착층의 굴절률을 고려해 설계함으로써 입력 광원이 UV 접착 층을 통과할 때의 광경로 이동(shift) 현상을 최소화하였다. 또한, AR 광학계를 설계할 때 축외 수차를 보정하고 양산에 적합하도록 2개의 비구면을 사용했다. 끝으로 HMD 양산을 위해 두께 11 mm, 대각선 화각(diagonal field of view) 40°, 무게 11.3 g의 비구면 AR 광학계를 설계하고 제작하였다.

• Current Optics and Photonics
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• 제4권2호
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• pp.121-126
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• 2020

With the increasing demand for head-mounted display applications, the image quality provided by a near-eye display device is a key factor in satisfying the consumer. Among various techniques to realize a near-eye display that has a thinner volume than the working distance of a human eye, a lightfield image-generation method based on a pinhole array is attracting much attention, with its simple and thin structure. In this paper, we propose a numerical analysis of the visual parameters and verifications with computational reconstruction.

• 한국항해학회지
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• 제24권3호
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• pp.133-140
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• 2000

The paper deals with the implementation of prototype Ship Simulator system (VRSS) by Virtual Reality techniques with Head Mounted Display (HMD) device. The prototype VRSS was consists of PC-based human sensors, object oriented operating system. In addition, two kinds of databases arranged from Head Related Transfer Functions and 3D object models were used to create 3D sea sound, and to construct virtual world, respectively. Using the prototype system, we carried out some simulation tests for the overtaking situation to prevent collisions at sea, and discussed on the usability of the system. As results from simulations, the prototype VRSS can provide multisensory and interactive display environment. The results gave rise to the user interaction with 3D objects that give realistic reproduction of navigational environments under a given scenario. Thus, we found that the prototype VRSS should be one of the next-generation ship simulation system.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.973-974
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• 2008

Optically transparent and flexible electronic circuits and displays are attractive for next-generation visual technologies, including windshield displays, head-mounted displays, and transparent screen monitors. Here we report on the fabrication of transparent transistors and circuits based on the combination of nanoscopic dielectrics and organic, inorganic, or hybrid semiconductors. Furthermore, the first demonstration of a transparent and flexible AMOLED display driven solely by $In_2O_3$ nanowire transistors (NWTs) is reported. The display region exhibits an optical transmittance of ~35% and a green peak luminance of ${\sim}300\;cd/m^2$. These results indicate that NWT-based drive circuits are attractive for fully transparent display technologies.