• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.51-54
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• 2020

본 논문에서는 360 도 VR 영상을 전송하는 기법의 일종인 타일 기반 전송을 MMT(MPEG Media Transport) 프로토콜 기반으로 구현하기 위하여 영상의 공간 분할 정보를 전달하는 방법을 소개한다. 360 도 VR 영상 전송은 대용량 미디어 전송인 동시에 사용자의 움직임에 따라 신속하게 적응적 영상을 전달해야 한다. 타일 기반 전송은 HEVC(High Efficiency Video Coding)의 MCTS(Motion Constrained Tile Sets) 기법을 이용하여 뷰포트에 해당하는 타일들을 고화질로 전달함으로써 이러한 요구사항을 해결한다. 반면, MMT 프로토콜은 초저지연 고화질 영상 전송에 유리한 기술로써 사용자의 시점 변화에 따라 기민하게 영상의 품질을 변환시킬 수 있다. 따라서 HEVC 의 SEI(Supplemental Enhancement Information) 메시지에 포함되는 타일들의 공간 분할 정보를 MMT 프로토콜에 적용하는 방식에 따라 적응적 타일 기반 전송 기법의 효율을 높일 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.194-196
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• 2017

최근 들어 VR 관련 기술이 발전하고 대중화가 됨에 따라 VR 하드웨어 기술 이외에도 VR 영상에 대한 개발과 연구에 대한 관심이 증가하고 있다. 이러한 VR 영상을 제작하기 위해서는 360 도의 전방위 촬영, 영상의 스티칭 및 프로젝션 그리고 사용자의 시야점획득을 통한 렌더링등과 같은 기술이 필요하다. 그러나 영상들의 스티칭, 프로젝션 등의 여러 단계의 과정을 거치면서 원 영상에 비하여 많은 왜곡이 발생하게 된다. 따라서 본 논문에서는 이러한 제작과정 중 발생하는 기하학적 왜곡에 대해 분석한다.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.463-470
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• 2017

Currently, virtual reality contents using VR images are spotlighted since they can be easily created and utilized. But because VR images are in a state of lack of interaction, there are limitations in their applications and usability.In order to overcome this problem, we propose a new method in which 360 degree panorama image and game engine are utilized to develop a high resolution of interactive VR service in real time. In particular, since the background image, which is represented by a form of panorama image, is pre-generated through a heavy rendering computation, it can be used to provide a immersive VR service with a relatively small amount of computation in run time on a low performance device. In order to show the effectiveness of our proposed method, an interactive game of a virtual zoo environment was implemented and illustrated showing that it can improve user interaction and immersion experience in a pretty good way.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.193-198
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• 2018

Applying VR technology to animation areas is emerging as a trend of recent years. So if you use this VR technology in traditional ink animation, 2D art piece is expected to be equipped with a new narrative style and visual and auditory language, making it a new animation genre. There's a lot of technical difficulties in putting the existing 2D ink image on a 360 degree display. VR ink animation has been created that gives depth to VR space by using layer extraction method based on depth of distance and placing layers extracted on curved surface that is aligned with depth in 360-degree space in the image of ink painting, which is the background of traditional ink animation. In the text, we took an overview on problems generated in extracting layers of distant view, close-range view and middle distant view from the existing image of ink painting and made suggestions of an effective way to approach them.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.685-697
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• 2020

Immersive media videos, such as panorama and 360-degree videos, must provide a sense of realism as if the user visited the space in the video, so they should be able to represent the reality of the real world. However, in panorama and 360-degree videos, objects appear to overlap or disappear due to parallax between cameras, and such parallax distortion may interfere with immersion of the user's content. Accordingly, although many video stitching algorithms have been proposed to overcome parallax distortion, parallax distortion still occurs due to the low performance of the Object detection module and limitations of the Seam generation method. Therefore, this paper analyzes the limitations of the existing video stitching technology and proposes a method for detecting and correcting parallax distortion of video stitching using the LDPM (Local Differential Pixel Mean) image evaluation method that overcomes the limitations of the video stitching technique.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.1-5
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• 2011

The brand-new small output radio equipment which is over than 800MHz has an all-in-one interior antenna. We suggested new measuring method and developed related equipment because all-in-one radio equipment's performance evaluation requests old way, which is measuring transmitter output and antenna capacity separately, to be changed. That is, origin of small radio equipments with the 360 degree field measured by measuring the TRP, and also 360 degree opposite reception level measured at the radio equipment by measuring the TIS to make a quantitative evaluation was to be. Furthermore, we made managing frequencies, all-in-one radio equipment's best design and capacity management efficiently by measuring the gain of an antenna mounted on a PCB, the circuit around the genetic material, conductive material on the effects of radiation or the reception level.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.27-38
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• 2017

This Paper Presents a Method for Stitching a Large Number of Images Recorded by a Large Number of Individual Users Through a Cellular Phone Camera at a Venue. In Contrast to 360 Camera Solutions that Use Existing Fixed Rigs, these Conditions must Address New Challenges Such as Time Synchronization, Repeated Transformation Matrix Calculations, and Camera Sensor Mismatch Correction. In this Paper, we Solve this Problem by Updating the Transformation Matrix Using Time Synchronization Method Using Audio, Sensor Mismatch Removal by Color Transfer Method, and Global Operation Stabilization Algorithm. Experimental Results Show that the Proposed Algorithm Shows better Performance in Terms of Computation Speed and Subjective Image Quality than that of Screen Stitching.

• Journal of IKEEE
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• v.24 no.2
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• pp.419-425
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• 2020

The market size of immersive 360-degree video contents, which are noted as one of the main technology of the fourth industry, increases every year. However, since most of the images are distributed through illegal distribution networks such as Torrent after the DRM gets lifted, the damage caused by illegal copying is also increasing. Although filtering technology is used as a technology to respond to these issues in 2D videos, most of those filtering technology has issues in that it has to overcome the technical limitation such as huge feature-point data volume and the related processing capacity due to ultra high resolution such as 4K UHD or higher in order to apply the existing technology to immersive 360° videos. To solve these problems, this paper proposes a feature-point recognition ratio improvement method for immersive 360-degree videos using deep learning technology.

• Korean Journal of Optics and Photonics
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• v.20 no.1
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• pp.48-52
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• 2009

We make a simple electrically controllable linear polarization rotator over $360^{\circ}$ without loss by using a thick ECB(electrically controlled birefringence) liquid crystal cell and a quarter wave plate at 514.5 nm wavelength. Its operating principle can be analyzed and explained by using simple polarization analysis and experimental data. We demonstrate that the degree of polarization of the rotator is 0.964 and the temporal variation for 1 week lies within ${\pm}1$ degree. We can easily solve the problem of nonlinearity of the dependence of the rotational angle of linear polarization on the applied voltage by changing the utilized voltage range or its fitting curve.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.4
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• pp.53-61
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• 1996

A distribution photometer was constructed to measure the angular distribution of luminous intensity of light sources and the reflected luminance of retroreflectors. This system incorporates a goniometer to rotate test light source(360 degree in yaw rotation and $\pm$30 degree in pictch rotation), a photomultiplier tube as light detector, light projector for retroreflection measurements, and the control and display unit. The ranges of luminous Intensity measurements and observation angles are 0.01~199900 cd and 0.2~1.5 degree respectively. The uncertainty of luminous intensity measurements is $\pm$3%. This paper describes the construction of the distribution photometer and the performance characteristics.