• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.133-136
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• 2003

In this paper, we propose a low bit-rate embedded video coding scheme with 3-D block partition in the wavelet domain. The proposed video coding scheme includes multi-level three dimensional dyadic wavelet decomposition, raster scanning within each subband, partitioning of blocks, and adaptive arithmetic entropy coding. Although the proposed video coding scheme is quite simple, it produces bit-streams with good features, including SNR scalability from the embedded nature. Experimental results demonstrate that the proposed video coding scheme is quite competitive to other good wavelet-based video coders in the literature.

• 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.

• 정보처리학회논문지B
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• 제9B권3호
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• pp.351-358
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• 2002

DCT(Discrete Cosine Transform) 기반 동영상 압축 기법은 블록화 현상과 해상도 변화 시 픽셀의 손상이 생기는 단점이 있다. DWT(Discrete Wavelet Transform)을 기반한 기법은 이러한 문제점을 극복할 수 있다. Wavelet을 기반한 동영상 부호화 기법 중 하나인 SAMCoW(Scalable Adaptive Motion Compensation Wavelet)에서 화면내 부호화와 움직임 보상된 오차 영상은 EZW(Embedded Zerotree Wavelet) 부호화 방식으로 부호화한다. 그러나 움직임 보상된 오차 영상의 wavelet 변환 계수의 특성은 정지 영상의 wavelet 변환 계수의 특성과는 다르다. 신호의 에너지는 대부분의 정지 영상의 경우와는 달리 저주파 대역에 집중되지 않고 오히려 모든 주파수 대역에 고르게 분포한다. 본 논문에서는 이러한 특성을 이용한 새로운 동영상 부호화 방식을 제안하였다. EZW 부호화 대신 고주파 성분이 많이 포함된 영상의 부호화에 효율적이며 계수사이의 대역별 상관관계에 의존하지 않는 공간 부호화를 화면내 부호화와 화면간 부호화에 적용하였다. 공간 부호화는 EZW와는 달리 wavelet 분해를 통해 얻어진 각 대역을 대역간의 상관 관계를 이용하지 않으면서 각 대역내의 중요 계수의 존재 여부와 위치를 점진적으로 부호화하는 기법이다. Wavelet 기반 동영상 부호화에 EZW 부호화 대신 공간 부호화를 적용하였을 때 우수한 성능을 나타내었다.

• 한국정보처리학회논문지
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• 제4권10호
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• pp.2629-2639
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• 1997

최근 초저속 전송 매체용 비디오 코딩 기법에 대한 관심이 높아지고 있다. 그러나 기존의 블럭을 기반으로 하는 변환 코딩기법들은 비트율 제한으로 인해 블럭화 현상 등으로 화질 열화가 심하다. 본 논문에서는 초저속 전송 매체를 위하여 웨이브릿 변환과 다중해상도 움직임 추정 및 보상 기법을 이용하는 비디오 코딩 시스템을 제안한다. 제안된 시스템은 non-stationary 신호를 적응적으로 표현하며, 인간 시각 특성을 잘 반영하는 웨이브릿 변환을 사용한다. 웨이브릿 변환된 계수들은 움직임 추정 및 보상 후 예측 오차의 크기에 따라서 다양한 모드로 코딩된다. 이와 함께 일정한 화질을 유지하기 위하여 간단한 버퍼 제어 기법을 사용한다. 실험을 통하여 제안된 기법은 블럭화 현상이 줄어들며, 기존의 블럭을 기반으로 하는 변환 코딩 기법보다 복원 영상의 화질이 좋음을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.190-192
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• 2004

In this paper, we propose a low bit-rate embedded video compression scheme with 3-D block partition coding in the wavelet domain. The proposed video compression scheme includes multi-level 3-dimensional dyadic wavelet decomposition, raster scanning within each subband, formation of block, 3-D partitioning of block, and adaptive arithmetic entropy coding. Although the proposed video compression scheme is quit simple, it produces bit-stream with good features, including SNR scalability from the embedded nature. Experimental results demonstrate that the proposed video compression scheme is quit competitive to other good wavelet-based video coders in the literature.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.900-903
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• 2002

This paper proposes the use of wavelet packet transform in a transform based video coding scheme, which is mainly used in low/very low bit-rate video coding schemes i.e. H.263 standard. In the experiments, the discrete cosine transform in the video coding scheme is replaced by the wavelet packet transform, and the improved performance in term of peak signal to noise ratio is measured and compared with the results obtained from the coding scheme implementing the ordinary wavelet transform. The experimental results show an impressive improvement obtained from the use of wavelet packet transform.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.802-805
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• 2007

A hardware architecture is presented of a wavelet based multiple line addressing driving scheme for passive matrix displays using the FPGA (Field Programmable Gate Arrays), which will be integrated in the scalable video coding $architecture^{[1]}$. The incoming compressed video data stream will then directly be transformed to the required column voltages by the hardware architecture without the need of employing the video decompression.

• 한국통신학회논문지
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• 제21권4호
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• pp.822-833
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• 1996

The video coding for very low bit rate has recently received considerable attention, but conventional block based transform coding schemes suffer from the blocking effect for the constraints of bit rates. In this paper, we present a video coding sysem suing multi-resolution motion estimation/compensation with variable size block(VMRME/C) and multi-resolution vector quantization(MRVQ) in wavelet transform domain for very low bit rate coding. It is shown that the presented scheme has better performance in the peak signal-to-nose ratio(RSNR) by 0.2-0.6 dB as well as subjective quality than that of conventional block based transform video coding techniques(especially, H. 263 which is DCT based video coding).

• 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.

• ETRI Journal
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• 제27권6호
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• pp.713-724
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• 2005

This paper focuses on the problem of key-frames coding and proposes a new promising approach based on the use of fractals. The summary, made of a set of key-frames selected from a full-length video sequence, is coded by using a 3D fractal scheme. This allows the video presentation tool to expand the video sequence in a "natural" way by using the property of the fractals to reproduce the signal at several resolutions. This feature represents an important novelty of this work with respect to the alternative approaches, which mainly focus on the compression ratio without taking into account the presentation aspect of the video summary. In devising the coding scheme, we have taken care of the computational complexity inherent in fractal coding. Accordingly, the key-frames are first wavelet transformed, and the fractal coding is then applied to each subband to reduce the search range. Experimental results show the effectiveness of the proposed approach.