• Broadcasting and Media Magazine
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• v.24 no.4
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• pp.102-108
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• 2019

VVC(Versatile Video Coding)는 H.264/AVC(Advanced Video Coding)와 H.265/HEVC(High Efficiency Video Coding)의 엔트로피 코딩 기술로 사용되었던 CABAC(Context-based Adaptive Binary Arithmetic Coding)을 기반으로하여 압축율과 처리율을 향상시킬 수 있는 다양한 기술들이 채택되어 현재 CD(Committee Draft)가 완성되었고 참조 모델인 VTM6.0이 정식으로 배포되었다. 본 논문에서는 VVC Draft 6에 채택된 엔트로피 코딩 관련 기술들과 H.265/HEVC의 엔트로피 코딩의 차이점을 설명하고 엔트로피 코딩의 압축 성능과 엔트로피 코딩의 복잡도를 분석한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.138-139
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• 2010

본 논문은 저복잡도 비디오 부/복호화를 위한 엔트로피 부호화 기반의 분산 비디오 코딩 방법을 제안한다. 제안하는 엔트로피 부호화 기반의 분산 비디오 코딩은 복호기의 복잡도를 줄이기 위하여 기존의 분산 비디오 코딩에서 사용하는 채널코딩을 이용하는 것이 아니라 엔트로피 코딩을 이용하여 부호화를 수행한다. 제안하는 방법에서 복호가는 움집임 추정을 수행하고 그 결과인 움직임 백터를 부호기로 전송하며, 부호기는 전송받은 움직임 백터를 초기 움직임 백터로 하여 움직임 백터 값의 갱신을 수행한다. 제안한 방법의 성능을 평가하기 위하여 기존의 분산 비디오 코딩 방법과 복호기 복잡도를 비교한 결과 99%의 복잡도 감소가 있었고, H.264/AVC의 All Intra 방법과 비교하여 20.3%의 비트율 감소가 있었다.

• Journal of IKEEE
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• v.17 no.3
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• pp.352-359
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• 2013

This paper proposes an entropy coding unit for H.264/AVC baseline profile. Entropy coding requires code tables for macroblock encoding. There are patterns in codewords of each code tables. In this paper, the patterns between codewords are analyzed to reduce the hardware cost. The entropy coding unit consists of Exp-Golomb unit and CAVLC unit. The Exp-Golomb unit can process five code types in a single unit. It can perform Exp-Golomb processing using only two adders. While typical CAVLC units use various code tables which require large amounts of resources, the sizes of the tables are reduced to about 40% or less of typical CAVLC units using relationships between table elements in the proposed CAVLC unit. After the Exp-Golomb unit and the CAVLC unit generate code values, the entropy unit uses a small size shifter for bit-stream generation while typical methods are barrel shifters.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.383-385
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• 2007

웨이블릿 화상 코딩 기법은 자연적으로 레이어드된 비트스트림을 생성해 내기 때문에, 주파수 제한적인 채널 상황에서 에러에 강한 성능을 나타내고 있다. 본 논문에서는 Progressive Image Coder의 성능을 비교하고 평가하는 새로운 기법인 시각적 엔트로피를 이용해, 웨이블릿 영역에서 시각적인 가중치를 이용해 정량화하려고 한다. 이 시각적인 가중치는 주파수 영역과 공간 영역에서, 인간의 시각 체계(HVS, human visual system)에 기반 하여 만들어진 것으로, 웨이블릿 계수들의 코딩 순서를 결정하는 기준으로 사용되고, 이렇게 해서 시각적인 화질을 개선할 수가 있다. 정규화된 채널 용량이 0.3일 때, 전송 이득은 시각적 엔트로피로 측정해 보았을 때 23% 이상 얻을 수 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.209-213
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• 2010

In this paper, an efficient predictor for entropy coding is proposed. It adaptively selects one of two prediction errors obtained by MED(median edge detector) or GAP(gradient adaptive prediction). The reduced error is encoded by existing entropy coding method. Experimental results show that the proposed algorithm can compress higher than existing predictive methods.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.39-49
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• 2012

Demand for high resolution video services leads to active studies on high speed video processing. Especially, widespread deployment of multi-core systems accelerates researches on high resolution video processing based on parallelization of multimedia software. Previously proposed parallelization approach could improve the decoding performance. However, some parallelization methods did not consider the entropy decoding and others considered only a partial decoding parallelization. Therefore, we consider parallel entropy decoding integrated with other parallel video decoding process on a multi-core system. We propose a novel parallel decoding method called Integrated Parallelization. We propose a method on how to optimize the parallelization of video decoding when we have a multi-core system with many cores. We parallelized the KTA 2.7 decoder with the proposed technique on an Intel i7 Quad-Core platform with Intel Hyper-Threading technology and multi-threads scheduling. We achieved up to 70% performance improvement using IP method.

• Annual Conference on Human and Language Technology
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• 1989.10a
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• pp.54-57
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• 1989

본 논문에서는 정보원의 집합이 여러개의 부집합으로 나누어지며 정보 발생 방법은 이들 부집합을 순서적으로 선택한 후 그 부집합에서 확률에 따라 원소를 발생시키는 성질을 갖는 정보원을 인코딩할 때 데이타를 압축시킬 수 있는 엔트로피 감소 모델을 제시하였다. 방법은 정보를 전송하는 과정에서 정보원이 갖고있는 성질에 관한 정보를 제외시킴으로서 평균 정보량 즉 엔트로피를 줄이는 것이다. 이와 같은 원리로 인코딩을 하면 데이타를 압축시킬수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.35-44
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• 2004

In this paper, we design an efficient VLSI architecture of entropy coding algorithm in JPEG2000. Entropy coder is a context-based binary arithmetic encoder, and composed of a Context Extractor(CE) and an Arithmetic Coder(AC). We speed-up CE by skipping no-operation bits in coding passes, and AC is to be performed based on MQ coder. Because of using Qe value associated with each allowed context and probability estimation, MQ coder is a multiplication free coder that reduces computation loads and makes simple the structure of arithmetic coder. We have developed and synthesized the VHDL models of CE and AC pairs using Xilinx FPGA technology. The proposed architecture operates up to 30MHz.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.133-143
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• 2011

In this paper, a complexity-balancing algorithm is proposed for distributed video coding based on entropy coding. In order to reduce complexity of DVC-based decoders, the proposed method employs an entropy coder instead of channel coders and the complexity-balancing method is designed to improve RD performance with minimal computational complexity. The proposed method performs motion estimation in the decoder side and transmits the estimated motion vectors to the encoder. The proposed encoder can perform more accurate refinement using the transmitted motion vectors from the decoder. During the motion refinement, the optimal predicted motion vectors are decided by the received motion vector and the predicted motion vectors and complexity load of block is allocated by adjusting the search range based on the difference between the received motion vector and the predicted motion vectors. The computational complexity of the proposed encoder is decreased 11.9% compared to the H.264/AVC encoder and that of the proposed decoder are reduced 99% compared to the conventional DVC decoder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.707-715
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• 2008

This paper proposes an algorithm for efficient compression gray-level images by entropy encoder. The issue of the proposed method is to replace original data of gray-level images with particular ranked data. For this, first, before encoding a stream of gray-level values in an image, the proposed method counts co-occurrence frequencies for neighboring pixel values. Then, it replaces each pay value with particularly ranked numbers based on the investigated co-occurrence frequencies. Finally, the ranked numbers are transmitted to an entropy encoder. The proposed method improves the performance of existing entropy coding by transforming original gray-level values into rank based images using statistical co-occurrence frequencies of gray-level images. The simulation results, using gray-level images with 8-bits, show that the proposed method can reduce bit rate by up to 37.85% compared to existing conventional entropy coders.