• 대한의용생체공학회:의공학회지
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• 제20권3호
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• pp.265-274
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• 1999

본 논문에서는 3차원 의료 영상에 적합한 interframe 부호화 알고리즘을 제안하였다. 제안된 알고리즘은 움직임 추정/보상과 변환 부호화를 사용하는 동영상 압축 방법에 기초를 두고 있다. 이 알고리즘에서는 움직임 추정을 위해 와핑 방법이 채택되었다. 그리고, 부호화 효율을 향상시키기 위해 적응적 모드 선택을 사용하여 웨이블릿 변환 영역에서 움직임 조상된 오차 영상과 원 영상을 혼합한다. 이렇게 혼합된 영상은 제로트리 부호화 기법에 의해 압축된다. 본 논문은 제안된 방법이 3차원 의료 영상의 부호화에 매우 유용함을 증명하였다. 모의실험결과는 제안된 방법이 슬라이스 간의 간격과 무관하게 항상 좋은 결과를 얻을 수 있도록 하고, 그럼으로써 3차원 의료 영상 압축에 매우 바람직하다는 사실을 보여준다.

• ETRI Journal
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• 제28권2호
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• pp.145-154
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• 2006

In the decoding process associated with interframe wavelet coding, the inverse wavelet transform requires high computational complexity. However, as video technology starts to pervade all aspects of our lives, decoders are becoming required in various devices such as PDAs, notebooks, PCs, and set-top boxes. Therefore, a decoder's complexity needs to be adapted to the processor's computational power, and consequently a low-complexity codec is also required for scalable video coding. In this paper, we propose a method of controlling and lowering the complexity of the spatial wavelet transform while sustaining the same coding efficiency as that currently afforded. In addition, the proposed method may alleviate the ringing effect for slowly changing image sequences.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1454-1456
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• 1987

Space domain image coding with VQ [9, 10, 11] has been very effective at low rates. To achieve quality at lower rates, it is necessary to exploit spaial redundancy over a larger region of pixels than is possible with general VQ. This paper presents a interframe coding algorithm which is capable of obtaining better performance and lower bi t rate than those of the general interframe coding. The performance is evaluated on the basis of SNR (Signal to Noise Ratio), memory requirements and bit rate.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1987년도 춘계학술발표회 논문집
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• pp.31-34
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• 1987

A new efficientcoding system which can transmit video conferenceof viedeophone signals at a 64kbps is proposed. In addition to the interframe and CRC (Conditional Repleni shment Coding) system, BTVQ (Binary Tree searched Vector Quantizer)and RLC (Run Length Coding) methods are incorporated. Couble buffer memory is used for simple comtrol of channel symbol transmission and memory underflow And also buffer memory onerfolw is easily controlled by the thresholds of a MAD (Moving Area Betector)

• ETRI Journal
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• 제24권4호
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• pp.280-289
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• 2002

In this work, we present a novel approach to the bit allocation problem that aims to minimize overall distortion subject to a bit rate constraint. The optimal solution can be found by the Lagrangian method with dynamic programming. However, the optimal bit allocation for block-based interframe coding is practically unattainable because of the interframe dependency of macroblocks caused by motion compensation. To reduce the computational burden while maintaining a result close to the optimum, i.e., near optimum, we propose an alternative method. First, we present a partitioned form of the bit allocation problem: a "frame-level problem" and "one-frame macroblock-level problems." We show that the solution to this new form is also the solution to the conventional bit allocation problem. Further, we propose a bit allocation algorithm using a "two-phase optimization technique" with an interframe dependency model and a rate-distortion model.

• 대한의용생체공학회:의공학회지
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• 제18권3호
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• pp.223-231
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• 1997

본 논문에서는 3차원 의료 영상의 압축을 위한 인터프레임 부호화 방법을 제안한다. 슬라이스 사이의 변화를 뼈나 조직의 움직임으로 간주하여 움직임 보상 기법을 통해 이전 프레임으로부터 현재 프레임을 예측하고, 변환 부호화를 사용하여 오차 영상을 압축한다. 의료 영상의 슬라이스 사이의 복잡한 변화를 잘 예측하기 위해 동영상 부호화에서 가장 널리 사용되는 블럭 정합 알고리즘 (BMA) 대신 bilinear 변환을 통한 영상 warping을 사용하였다. 이 warping 방법은 슬라이스 사이에서 object가 없어지는 경우 예측 성능이 저하되는데, 이러한 단점을 보완하기 위해 블럭 겹침 움직임 보상 (OBMC) 기법을 결합하였다. 움직임 보상된 오차 영상의 부호화에는 EZW 부호화를 사용하였고, 이 때 각 프레임의 wavelet 계수의 양자화 오차를 동일하게 하여 프레임마다 일정한 화질을 얻도록 하였다. 모의 실험에서 warping을 사용한 인터프레임 부호화는 각 프레임을 독립적으로 부호화하는 방식보다 높은 압축 성능을 보였고, OBMC를 결합함으로써 warping만을 사용했을 때보다 성능이 더 개선되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.168-171
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• 1988

This paper describes CODEC based on hybrid interframe and BTVQ including CRC(Conditional Replenishment Coding) system and RLC(Run Length Coding) method. Based upon the algorithm described in this paper, a practical CODEC has been designed for video conference and video phone use at 54Kbps using an ADSP-2100 as a CPU.

• 대한전자공학회논문지
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• 제25권12호
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• pp.1513-1521
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• 1988

BMA, which is generally adopted in low bit-rate motion-compensated coding, performs properly under an assumption of rigid-body motion of moving objects. Since, however, the assumption can not be held in practical coding , the prediction errors with low correlation are generated. For effective transform codings of the interframe prediction errors, we propose a new transform coding technique which decomposes the prediction errors into two sources and then transforms them with DCT and WHT consecutively. The performance of the proposed algorithm is compared to those of the two conventional algorithms in terms of bit rate and subjective image quality.

• 한국통신학회논문지
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• 제22권8호
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• pp.1707-1714
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• 1997

This paper proposes a novel algorithm for fractal coding of image sequence, based on the CPM (Circular Prediction Mapping) and the NCIM (Non Contractive Interframe Mapping). In the CPM and the NCIM, each range block is approximated by a domain block in the adjacent frame, which is of the same size as the range block. Also, in this paepr, we propose a coding scheme of color components and an algorithm for controlling the bit rate, resepectively, for practical implementation of the fractal coder. The computer simulation results on real image sequences demonstrate that the proposed algorithm provides very promising performance at low bit-rate, below 256 Kbps.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.236-239
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• 1988

Prediction errors generated by motion compensated coding are coded with transform coding techniques as DCT. The performance of transform coding techniques are lowered mainly due to the source characteristics with a great deal of zero populations and plus-minus sign changes, i.e., low correlation. In this paper a transform coding scheme which adopts a decomposition of prediciton errors into two sources is proposed and compared its performance with conventional scheme.