• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2020년도 하계학술대회
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• pp.497-499
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• 2020

포인트 클라우드는 다수의 3D 포인터를 사용한 3D 데이터의 표현 방식 중 하나이며, 멀티미디어 획득 및 처리 기술의 발전에 따라 다양한 분야에서 주목하고 있는 기술이다. 특히 포인트 클라우드는 3D 데이터를 정밀하게 수집하고 표현할 수 있는 장점을 가진다. 하지만 포인트 클라우드는 방대한 양의 데이터를 가지고 있어 효율적인 압축이 필수적이다. 이에 따라 국제 표준화 단체인 Moving Picture Experts Group에서는 포인트 클라우드 데이터의 효율적인 압축을 위하여 Video based Point Cloud Compression(V-PCC)와 Geometry based Point Cloud Coding에 대한 표준을 제정하고 있다. 이 중 V-PCC는 기존 High Efficiency Video Coding(HEVC) 표준을 활용하여 포인트 클라우드를 압축하여 활용성이 높다는 장점이 있다. 본 논문에서는 V-PCC에 사용하는 HEVC 코덱을 2020년 7월 표준화 완료될 예정인 Versatile Video Coding으로 대체하여 V-PCC의 압축 성능을 더 개선할 수 있음을 보인다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.908-911
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• 2002

Over the past 30 years, many efficient 2D video coding techniques have been presented and developed from many research centers for commercialization. However, direct application of these monocular compression schemes is not optimal for stereo video coding. In this paper, we present a new technique for coding stereo video sequences based on Discrete Wavelet Transform (DWT). The proposed technique exploits Zerotree Entropy Coding (ZTE) that makes use of the wavelet block concept to achieve low bit rate stereo video coding. The one of two image streams, called main stream, is independently coded by modified MPEG-4 encoder and the other stream, called auxiliary stream, is coded by predicting from its corresponding image, its previous image or its follow image.

• 한국통신학회논문지
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• 제34권10B호
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• pp.1093-1103
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• 2009

본 논문에서는 효율적인 보조 정보 생성을 통한 새로운 분산 다시점 비디오 코딩 기법을 제안한다. 분산 비디오 코딩은 원영상과 디코더에서 생성한 보조 정보 간의 오차를 채널 코딩 기법으로 정정한다. 따라서 보조 정보를 정확히 만들수록 분산 비디오 코딩의 성능은 좋아지게 된다. 제안한 기법에서는 깊이지도를 기반으로 하는 다시점 비디오 코딩에 분산 비디오 코딩 기법을 적용한다. 또한 깊이지도를 이용한 3차원 워핑을 통해 인접한 시점의 영상으로부터 보조 정보를 생성하고, 3차원 워핑과 시간 축 상의 인접한 영상을 이용하는 MCTI(motion compensated temporal interpolation)를 효율적으로 혼합하여 사용한다. 실험 결과 제안한 기법으로 생성한 보조 정보는 MCTI와 3차원 위핑을 따로 사용한 방법보다 평균 0.97dB의 PSNR이 향상되었음을 알 수 있었다. 또한 R-D 곡선 상에서 동일 PSNR 대비 평균 8.01%의 비트율이 감소되었다.

• ETRI Journal
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• 제36권4호
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• pp.528-536
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• 2014

High Efficiency Video Coding (HEVC) is the most recent video coding standard to achieve a higher coding performance than the previous H.264/AVC. In order to accomplish this improved coding performance, HEVC adopted several advanced coding tools; however, these cause heavy computational complexity. Similar to previous video coding standards, motion estimation (ME) of HEVC requires the most computational complexity; this is because ME is conducted for three inter prediction modes - namely, uniprediction in list 0, uniprediction in list 1, and biprediction. In this paper, we propose an efficient inter prediction mode (EIPM) decision method to reduce the complexity of ME. The proposed EIPM method computes the priority of all inter prediction modes and performs ME only on a selected inter prediction mode. Experimental results show that the proposed method reduces computational complexity arising from ME by up to 51.76% and achieves near similar coding performance compared to HEVC test model version 10.1.

• 방송공학회논문지
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• 제24권1호
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• pp.132-141
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• 2019

매우 제한된 전송 대역을 이용하여 비디오 데이터를 전송해야 하는 필요성은, 광대역을 통한 비디오 서비스가 활성화되어 있는 현 시점에서도 꾸준히 존재한다. 본 논문에서는 초협대역 네트워크를 통한 저해상도 비디오 전송을 위해, 공간 확장형 스케일러블 비디오 코딩 프레임워크에서 기본 계층의 부호화된 프레임을 심층 신경망 기반 초해상화 기법을 이용하여 업스케일링 하여 향상 계층 부호화 시에 예측 영상으로 활용하여 부호화 효율을 높이는 방법을 제안한다. 기존의 스케일러블 HEVC (High efficiency video coding) 표준에서는 고정된 필터로 업스케일링을 하는데 비해, 본 논문에서는 초해상화 수행을 위해 학습된 심층신경망을 기존의 고정 업스케일링 필터를 대체하여 적용하는 스케일러블 비디오 코딩 프레임워크를 제안한다. 이를 위해 스킵 연결과 잔차 학습 기법 등이 적용된 심층 콘볼루션 신경망 구조를 제안하고, 비디오 코딩 프레임워크의 실제 응용 상황에 맞추어 학습시켰다. 입력 해상도가 $352{\times}288$이고 프레임율이 8fps인 영상을 110kbps로 부호화 하는 응용 상황에서, 기존의 스케일러블 HEVC 프레임워크에 비해 제안하는 스케일러블 비디오 코딩 프레임워크의 화질이 더 높고 부호화 효율이 우수함을 확인할 수 있었다.

• ETRI Journal
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• 제46권3호
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• pp.538-549
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• 2024

A conventional codec aims to increase the compression efficiency for transmission and storage while maintaining video quality. However, as the number of platforms using machine vision rapidly increases, a codec that increases the compression efficiency and maintains the accuracy of machine vision tasks must be devised. Hence, the Moving Picture Experts Group created a standardization process for video coding for machines (VCM) to reduce bitrates while maintaining the accuracy of machine vision tasks. In particular, in-loop filters have been developed for improving the subjective quality and machine vision task accuracy. However, the high computational complexity of in-loop filters limits the development of a high-performance VCM architecture. We analyze the effect of an in-loop filter on the VCM performance and propose a suboptimal VCM method based on the selective activation of in-loop filters. The proposed method reduces the computation time for video coding by approximately 5% when using the enhanced compression model and 2% when employing a Versatile Video Coding test model while maintaining the machine vision accuracy and compression efficiency of the VCM architecture.

• ETRI Journal
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• 제31권2호
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• pp.151-161
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• 2009

In this paper, we propose an adaptive multiview video coding scheme based on spatiotemporal correlation analyses using hierarchical B picture (AMVC-HBP) for the integrative encoding performances, including high compression efficiency, low complexity, fast random access, and view scalability, by integrating multiple prediction structures. We also propose an in-coding mode-switching algorithm that enables AMVC-HBP to adaptively select a better prediction structure in the encoding process without any additional complexity. Experimental results show that AMVC-HBP outperforms the previous multiview video coding scheme based on H.264/MPEG-4 AVC using the hierarchical B picture (MVC-HBP) on low complexity for 21.5%, on fast random access for about 20%, and on view scalability for 11% to 15% on average. In addition, distinct coding gain can be achieved by AMVC-HBP for dense and fast-moving sequences compared with MVC-HBP.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1762-1773
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• 2014

In this paper, a distributed image coding scheme for multi-view video through an efficient generation of side information is proposed. A distributed video coding technique corrects the errors in the side information, which is generated with the original image, by using the channel coding technique at the decoder. Therefore, the more correct the generated side information is, the better the performance of distributed video coding. The proposed technique is to apply the distributed video coding schemes to the image coding for multi-view video. It generates side information by selectively and efficiently using both 3-dimensional warping based on the depth map with spatially adjacent frames and motion-compensated temporal interpolation with temporally adjacent frames. In this scheme the difference between the adjacent frames, the sizes of the motion vectors for the adjacent blocks, and the edge information are used as the selection criteria. From the experiments, it was observed that the quality of the side information generated by the proposed technique was improved by the average peak signal-to-noise ratio of 0.97dB than the one by motion-compensated temporal interpolation or 3-dimensional warping. The result from analyzing the rate-distortion curves revealed that the proposed scheme could reduce the bit-rate by 8.01% on average at the same peak signal-to-noise ratio value, compared to previous work.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.298-300
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• 2004

In the decoding process of interframe wavelet coding, the inverse wavelet transform requires huge computational complexity. However, the decoder may need to be used in various devices such as PDAs, notebooks, PCs or set-top Boxes. Therefore, the decoder's complexity should be adapted to the processor's computational power. A decoder designed in accordance with the processor's computational power would provide optimal services for such devices. So, it is natural that the complexity scalability and the low complexity codec are also listed in the requirements for scalable video coding. In this contribution, we develop a method of controlling and lowering the complexity of the spatial wavelet transform while sustaining almost the same coding efficiency as the conventional spatial wavelet transform. In addition, the proposed method may alleviate the ringing effect for certain video data.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.57-60
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• 2008

In this paper, we describe the technology about multiview video coding which is a hot issue in diqital video coding. A multiview video coding (MVC) is able to provide a free view point and 3-D effect, resulting that it gives more realism to users. Now, the MVC has been standardized as an amendment of H.264/AVC. In this paper, we present not only the MVC standard but also relevant techniques which were under consideration in the MVC standardization.