• 전기전자학회논문지
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• 제17권3호
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• pp.352-359
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• 2013

본 논문에서는 H.264/AVC 베이스라인 프로파일을 위한 엔트로피 코딩 유닛을 제안한다. 엔트로피 코딩에서는 매크로블록 부호화를 위해 코드 테이블들을 사용한다. 이 코드 테이블에 있는 코드워드들 간에는 일정한 패턴이 존재하는데, 본 논문에서는 코드워드의 패턴을 분석하여 하드웨어 비용을 줄였다. 제안하는 엔트로피 코딩 유닛은 Exp-Golomb 유닛과 CAVLC 유닛으로 구성된다. Exp-Golomb 유닛은 하나의 유닛에서 5가지 코드타입을 처리하고, 코드 패턴을 이용하여 두 개의 덧셈기만으로 복잡한 Exp-Golomb 연산을 처리 할 수 있다. 기존의 CAVLC 유닛은 큰 사이즈의 코드 테이블을 필요로 한다. 본 논문에서는 테이블에 차분 코드워드들을 저장하여 기존 방식대비 테이블 크기를 40% 이하로 줄인다. 엔트로피 코딩 유닛은 생성된 코드워드들이 MSB에 코드값 0이 분포되는 패턴을 이용하여 쉬프터 사이즈를 대폭 줄였다.

• 한국통신학회논문지
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• 제22권7호
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• pp.1515-1522
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• 1997

Several image coding algorithms have been developed for the telecommunication and multimedia systems with high image quality and high compression ratio. In order to achieve low entropy and distortion, the system should pay great cost of computation time and memory. In this paper, the uniform cubic lattice is chosen for Lattice Vector Quantization (LVQ) because of its generic simplicity. As a transform coding, the Discrete Wavelet Transform (DWT) is applied to the images because of its multiresolution property. The proposed algorithm is basically composed of the biorthogonal DWT and the uniform cubic LVQ. The multiresolution property of the DWT is actively used to optimize the entropy and the distortion on the basis of the distortion-rate function. The vector codebooks are also designed to be optimal at each subimage which is analyzed by the biorthogonal DWT. For compression efficiency, the vector codebook has different dimension depending on the variance of subimage. The simulation results show that the performance of the proposed coding mdthod is superior to the others in terms of the computation complexity and the PSNR in the range of entropy below 0.25 bpp.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권6호
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• pp.1222-1236
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• 2010

In this paper, we propose an improved distributed multi-view video coding method that is robust to illumination changes among different views. The use of view dependency is not effective for multi-view video because each view has different intrinsic and extrinsic camera parameters. In this paper, a modified distributed multi-view coding method is presented that applies illumination compensation when generating side information. The proposed encoder codes DC values of discrete cosine transform (DCT) coefficients separately by entropy coding. The proposed decoder can generate more accurate side information by using the transmitted DC coefficients to compensate for illumination changes. Furthermore, AC coefficients are coded with conventional entropy or channel coders depending on the frequency band. We found that the proposed algorithm is about 0.1~0.5 dB better than conventional algorithms.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1240-1243
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• 2004

Multi-Valued Image Entropy Coding (MVIEC) is a new class of joint source channel coding, which reduces both input-width (1/4) and average current (0.36-1.3) for LCD source drivers. This paper describes the detail results on MVIEC for several image sets in order to verify the practical performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.609-612
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• 1999

In this paper, we propose wavelet transform image compression method such that an image is decomposed into multiresolutions using biorthogonal wavelet transform with linear phase response property and decomposed subbands are classified by maximum classification gain. The classified data is quantized by allocating bits in accordance with classified class informations within subbands through arbitrary set bit allocation algorithm. And then, quantized data in each subband are entropy coded. The proposed coding method is that the quantized data perform shuffling before entropy coding in order to remove sign bit plane. And the context is assigned by maximum correlation direction for bit plane coding.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.114-117
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• 2004

This paper proposes a novel algorithm for hybrid lossless audio coding, which employs integer discrete cosine transform. The proposed algorithm divides the input signal into frames of a proper length, decorrelates the framed data using the integer DCT and finally entropy-codes the frame data. In particular, the adaptive Golomb-Rice coding method used for the entropy coding selects an optimal option which gives the best compression efficiency. Since the proposed algorithm uses integer operations, it significantly improves the computation speed in comparison with an algorithm using real or floating-point operations. When the coding algorithm is implemented in hardware, the system complexity as well as the power consumption is remarkably reduced. Finally, because each frame is independently coded and is byte-aligned with respect to the frame header, it is convenient to move, search, and edit the coded data.

• 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.

• 한국산업정보학회논문지
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• 제6권1호
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• pp.39-47
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• 2001

A blocked zerotree coding algorithm for compression of subband image is proposed. Significance of blocks with respect to a certain threshold are coded with a set of transition rules for the significance of blocks. Significant blocks are quantized by vector quantization. The basic idea for this coding approach are: 1) Subband images are coded by blocks, 2) Important blocks based on the significance of blocks are coded and quantized, 3) Multiband codebook which is composed of sub-codebooks dedicated for each threshold and subband level is adapted to produce good reproduction vectors for vector quantization. The compression results are similar to Shapiro's zerotree coding even though ours are obtained without entropy coding of bit streams from blocked zerotree encoder. If an entropy coding is applied to the bitstream, PSNR will be improved.

• 한국통신학회논문지
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• 제29권8C호
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• pp.1055-1061
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• 2004

본 논문에서는 H.264/AVC 엔트로피 부호화 방식에서 다중 부호어를 이용한 효율적인 동적 부호화 방법을 제안한다. H.264/AVC에서 사용된 Exp-Golomb 부호어는 정적 확률 분포 특성 때문에 (7)에서 제시한 일원화 구문요소의 심볼 분포를 충분히 반영하지 못한다. 그러나 본 논문에서 제시한 다중 부호어 들은 다양한 통계적 특성을 나타낸다. 따라서 주어진 동영상에 따라 일원화 구문 요소를 부호화하기 위해 다중 부호어 들을 선택적으로 사용하는 동적 부호화 방법이 제안된다. 실험 결과에서는 제안한 방식이 (7)방식에 비해 화질의 열화 없이 압축 효율의 우수성을 보여준다.

• 한국통신학회논문지
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• 제29권9C호
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• pp.1244-1251
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• 2004

본 논문에서는 H.264/AVC 엔트로피 부호화 방식에서 다중 부호어를 이용한 효율적인 동적 부호화 방법을 제안한다. H.264/AVC 에서 사용된 Exp-Golomb 부호어는 정적 확률 분포 특성 때문에 [7]에서 제시한 일원화 구문요소의 심볼 분포를 충분히 반영하지 못 한다. 그러나 본 논문에서 제시한 다중 부호어들은 다양한 통계적 특성을 나다낸다. 따라서 주어진 동영상에 따라 일원화 구문 요소를 부호화하가 위해 다중 부호어들을 선택적으로 사용하는 통적 부호화 방법이 제안된다. 실험 결과에서는 제안한 방식이 [7] 방식에 비해 화질의 열화 없이 압축 효율의 우수성을 보여준다.