• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.73-74
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• 2021

This paper presents a scheme to downscale the patches in geometry atlas based upon its contents for MPEG Immersive Video (MIV). In proposed scheme, the geometric contents of a patch is analyzed across the intra period, and a decision is made, whether to downscale a patch or not. The patches containing homogeneous information is downscaled by half, while the patches having salient information about the object such as edges are retained. Experimental results show that the bitrate saving is achieved by incorporating the patch level downscaling.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.295-296
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• 2020

3DoF+ 비디오 부호화 표준을 개발하고 있는 MPEG-I 비주얼 그룹은 표준화 과정에서 참조 SW 코덱인 TMIV(Test Model for Immersive Video)를 개발하고 있다. TMIV 는 제한된 공간에서 동시에 여러 위치에서 획득한 뷰(view)의 텍스처(texture) 비디오와 깊이(depth) 비디오를 효율적으로 압축하여 임의 시점의 뷰 렌더링(rendering)을 제공한다. TMIV 에서 수행되는 깊이 비디오의 비트 심도 스케일링 및 압축은 깊이 정보의 손실을 발생하며 이는 렌더링(rendering)된 임의 시점 비디오의 화질 저하를 야기한다. 본 논문에서는 보다 효율적인 깊이 비디오 압축을 위한 히스토그램 등화(histogram equalization) 기반의 구간별(piece-wise) 깊이 매핑 기법을 제안한다. 실험결과 제안기법은 자연 영상(natural sequence)의 End-to-End 부호화 성능에서 평균적으로 3.1%의 비트율 절감이 있음을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.93-100
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• 2019

One of critical issues in dealing with 360-degree realistic contents is the performance degradation in searching and recognition process since they support up to 4K UHD quality and have all image angles including the front, back, left, right, top, and bottom parts of a screen. To solve this problem, in this paper, we propose an efficient search and comparison method for 360-degree realistic contents. The proposed method first corrects the distortion at the less distorted regions such as front, left and right parts of the image excluding severely distorted regions such as upper and lower parts, and then it extracts feature points at the corrected region and selects the representative images through sequence classification. When the query image is inputted, the search results are provided through feature points comparison. The experimental results of the proposed method shows that it can solve the problem of performance deterioration when 360-degree realistic contents are recognized comparing with traditional 2D contents.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.257-260
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• 2022

국제표준 3차원 포인트 클라우드 압축 기술인 MPEG(Moving Picture Experts Group)-I(Immersive) V-PCC(Video-based Point Cloud Compression)에는 점유 맵(Occupancy Map) 손실/무손실 압축 기술이 포함되어 있다. V-PCC는 기존에 보급되어 있는 2차원 비디오 코덱(H.264/AVC, HEVC, AV1 등)을 그대로 활용할 수 있는 장점이 있는데, 대부분의 소비자 영상 기기에 포함되어 있는 2차원 비디오 복호화기 HW는 무손실을 지원하지 않는다. 따라서 V-PCC 복호화기의 폭넓은 상용화를 위해서는 부호화기에서 점유 맵의 손실 압축이 필수적이다. 본 논문은 V-PCC 부호화기의 점유 맵을 최소한의 압축 효율 저하로 손실 압축하기 위해 다양한 파라미터 실험을 통한 최적의 파라미터 값을 제시한다.

• Journal of Korea Multimedia Society
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• v.17 no.1
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• pp.104-112
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• 2014

With recent development of virtual reality technology, coupled with the growth of the marine industry, virtual underwater simulation systems are under development in various studies, for educational purposes and to simulate virtual reality experiences. Current literature indicates many underwater simulation systems to date have focused on the quality of visual stimulus delivered through three-dimensional graphics user interface, limiting the reality of the experience. In order to improve the quality of the reality delivered by such virtual simulations, it is crucial to develop multi-sensory technology rather than focus on the conventional audio-visual interaction, which limits experiencer from the sense of underwater immersion and existence within the simulation. This work proposes the immersive multi-sensory effector system, delivering the users with a more realistic underwater experience. The sense of reality perceived was evaluated, as the main factor of the virtual reality system.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.948-955
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• 2019

As interests in 360-degree VR (Virtual Reality) video services enormously grow, compression and streaming technologies for VR video data have been rapidly developed. Quality Emphasized Region (QER) based streaming scheme has been developed as a kind of viewport-adaptive 360-degree video streaming technology for maintaining immersive experience and reducing bandwidth waste. For selecting a QER corresponding to the user's gaze coordinate, QER-based streaming scheme requires the calculation of Quality Emphasis Center (QEC) distance and signaling message delivery for requesting QER switching. QEC distance calculations require high computational complexity because of repeated calculations as many times as the number of QERs. Furthermore, the signaling message interval results in a trade-off relationship between efficient bandwidth usage and flexible QER switching. In this paper, we propose an improved QER selection algorithm based on MMT protocol to solve this problem. The proposed algorithm could achieve computational complexity reduction by using preprocessed QER_ID_MAP. Also, flexible QER switching could be achieved, as well as efficient bandwidth utilization by an adaptive adjustment of the signaling interval.