• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.417-426
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• 1996

In this paper, we report the effects of visual stimulation patterns in the postural balance control. We used the motor-driven cloth panel and HMD(Head Mounted Display) to evaluate the effect of visual stimulation patterns in the postural balance control. We also investigated the usefulness of HMD in the postural balance rehabilitation training system from the view of reducing the scale of experimental system. Our results showed that a vertical-strip visual pattern was more effective than the others in the postural balance control. It was also indicated that HMD might be applied to clinical use as a new postural balance training system.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.593-595
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• 2019

원격지의 로봇을 조작함에 있어, 원격지의 상황을 정확히 인식하는 것이 우선적으로 필요하다. 본 연구에서는 로봇에 설치된 스테레오 카메라를 통해 입력된 비디오를 네트워크를 통해 전달하고, 조작 공간에 있는 사용자가 Head Mounted Display(HMD) 기기를 통해 원격지의 상황을 현장감 있게 파악할 수 있는 비전 시스템을 구현했다. 로봇 내 S/W의 효과적인 통합을 위해 카메라 입력 처리 및 비디오 스트리밍은 Ubuntu의 ROS를 이용하여 구현됐으며, 조작 공간의 HMD 기기 및 관련 조작 센서 통합은 Windows 상에 구현하여, 실험을 통해 원격지의 상황을 25fps 수준의 HD 해상도 비디오로 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.135-138
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• 2001

증강현실 시스템을 구축하는데 있어 실시간 가상객체 위치 추적은 실세계와 가상객체를 정확하고 깊이감 있게 정합하고, 실세계 움직임에 따른 가상객체 위치변화 추적에 중요하다. 따라서 실시간 카메라 입력영상으로부터 가상객체의 위치를 추적하는데 있어 정확성과 함께 빠른 수행시간이 요구된다. 본 논문에서는 HMD(Head Mounted Display)장비에 장착된 두 개의 카메라로부터 관찰자의 시점 이동에 따른 가상객체 정합위치 정보를 입력받아 그 위치를 정확하게 인식하고 빠르게 추적하기 위하여 인위적인 랜드마크 형태를 정의하였으며, 실시간 입력영상으로부터 랜드마크 중심점 위치를 실시간으로 추적하기 위해 일정시간 간격마다 입력받은 첫 영상으로부터 얻은 랜드마크 영역 정보를 이용하여 중심점의 위치를 추적함으로써 수행시간을 줄이고자 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.64.2-64
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• 2001

In this paper, fabricated is a motion capture and attitude detection system for Head Mounted Display HMD composed of three low-price and low-grade micro gyroscopes and a micro-controller, To calculate attitude of a body, modified INS algorithm is used. Because the micro gyroscope has much bias drift error, scale factor error, and run-to-run bias error, the motion of a body can not be measured exactly if the general INS algorithm and micro gyroscopes are used. To reduce the errors, three accelerometers can be used. In this case, however, the size and power consumption become too large to use in HMD system. The modified INS algorithm use the grid map and the characteristics of the human motions.

• International Journal of Contents
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• v.15 no.1
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• pp.1-9
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• 2019

Since the VR market is expected to have a high growth, this study aimed to investigate the human factor-related determinants of user satisfaction with mobile VR headsets. A pre-study of customer reviews was conducted with the help of semantic network analysis to identify the core keywords for understanding negative and positive predictors of mobile VR headset experiences. Through laboratory testing with three different commercial models, the main study measured and identified the predictors of user satisfaction. From the results, five factors were extracted as valid predictor variables and used for regression analysis. These factors were immersion, VR sickness, usability, wear-ability and menu navigation interface. All the five predictors were proved to be significant determinants of the perceived user satisfaction with mobile VR headsets. Usability was the strongest predictor, followed by VR sickness and wear-ability. Practical and theoretical implications of the results were discussed.

• Journal of Broadcast Engineering
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• v.25 no.7
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• pp.1073-1080
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• 2020

360-degree video streaming technologies have been widely developed to provide immersive virtual reality (VR) experiences. However, high computational power and bandwidth are required to transmit and render high-quality 360-degree video through a head-mounted display (HMD). One way to overcome this problem is by transmitting high-quality viewport areas. This paper therefore proposes a motion-constrained tile set (MCTS)-based tile extractor for versatile video coding (VVC). The proposed extractor extracts high-quality viewport tiles, which are simulcasted with low-quality whole video to respond to unexpected movements by the user. The experimental results demonstrate a savings of 24.81% in the bjøntegaard delta rate (BD-rate) saving for the luma peak signal-to-noise ratio (PSNR) compared to the rate obtained using a VVC anchor without tiled streaming.

• Current Optics and Photonics
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• v.5 no.4
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• pp.402-408
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• 2021

An off-axis system refers to an optical system in which the optical axis and normal vector at the vertex of each surface do not match. The most important specification in an optical system is its focal length. Among the various methods for measuring the focal length, the most suitable method for the off-axis system is the method that adopts magnification. However, head-mounted display (HMD) optics must be measured while considering the virtual image distance, which is not infinity owing to product characteristics. For the virtual image distance, a camera with a focusing function was used. By measuring HMD optics via this magnification method, the error generated in this measurement was 0.68% of the HMD's focal length, which is within the 1%-3% range of the conventionally permitted design error for the focal length allowed at the optical design stage. Therefore, it can be verified that the measurement accuracy of the method proposed in this study is sufficiently feasible in practice.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.49-55
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• 2022

Hair styling has a significant influence on human social perception. An increasing number of people are learning hair styling and obtaining hair designer licenses. However, it takes a considerable amount of money and time to learn professional hairstyle and beauty techniques for hair styling. Since COVID-19, there has been a growing need for offline and video lectures due to the decline in onsite training opportunities. This study provides a field practice environment in which real hair beauty is performed in a virtual space. Further, the hairstyle that is most similar to the user's hair taken with a webcam or mobile phone is determined through an image matching system using the speeded up robust features (SURF) method. The matching hairstyle was created into a three-dimensional (3D) hair model. The created 3D hair model uses a head-mounted display (HMD) and a controller that enables finger tracking through mapping to reproduce the haircutting scissors' motion while providing a feeling of real hair beauty.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.59-61
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• 2021

뷰포트 예측은 360° VR(Virtual Reality) 영상 전송에서 사용자의 안정적인 콘텐츠 몰입을 위해 고안된 기법이다. 하지만 뷰포트 예측 모델의 정확도는 예측에 활용되는 데이터 또는 네트워크 상황에 따라 변동될 수 있다. 특히 사용자의 움직임은 뷰포트 예측 성능에 직접적인 영향을 주기 때문에 사용자의 움직임에 대한 정밀한 분석이 중요하다. 본 논문에서는 뷰포트 적응적 전송의 효율적인 개선을 위하여 HMD(Head-Mounted Display)의 속도가 뷰포트 예측에 미치는 영향을 분석한다.

• 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.