• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.797-800
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• 2001

영상 압축 분야에서 데이터의 압축이 필수적인데, 이때 가장 많은 중복성을 가지고 있는 시간적 중복성은 이전 프레임의 데이터를 이용하여 움직임 추정과 움직임 보상을 수행하고 추정된 움직임 벡터에 의해서 보상된 영상과 원 영상과의 차 신호를 부호화하여 데이터를 압축한다. 움직임 추정과 움직임 보상 기법은 비디오 영상압축에서 중요한 역할을 하지만 많은 계산량으로 인하여 실시간 응용 및 고해상도 응용에 많은 어려움을 가지고 있다. 만일 움직임 추정을 하기 전에 블록의 움직임을 예측할 수 있다면 이를 바탕으로 탐색 영역에서 초기 탐색점의 위치 및 탐색 패턴을 결정찬 수 있다. 본 논문에서는 움직임의 높은 시간적 상관성을 이용하여 초기 탐색점의 위치와 탐색 패턴을 결정함으로써 적응적으로 움직임 추정하는 새로운 기법을 제안하고 성능을 평가한다. 실험을 통하여 제안된 알고리즘은 계산량의 감소에 있어서 높은 성능 향상을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1058-1065
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• 2006

In this paper, we propose a new motion vector coding algorithm suitable for MPEG-4 Part 10 video coding standard. In the proposed algorithm, the amount of the motion for a given video sequence is Predicted by using a characteristic of the motion vector distribution for the neighboring blocks as well as the MB_type, which is the syntax element in the standard. And one of the independent coding and the combined coding methods is adaptively employed to compress the motion vector difference. Simulation results show that the proposed algorithm outperforms the conventional methods without additional memory and calculations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.1036-1043
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• 2005

In this paper, we propose a sequential motion vector recovery algorithm for H.264 video coding standard. Motion vectors of H.264 video coding standard cover relatively smaller areas than other standard, since motion estimation of H.264 takes place in the fashion of variable block size. Therefore, the correlation of motion vectors between neighboring blocks increases as the block size of motion estimation is lowered. Under the framework of sequential recovery, we introduce a motion vector recovery using $\alpha$-trimed mean filter. Experimental results show that proposed algorithm is useful in real time video delivery .with nearly comparable or better visual quality than previous approaches such as macro block boundary matching and Lagrage interpolation.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.199-204
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• 2002

Since motion estimation and motion compensation methods remove the redundant data to employ the temporal redundancy in images, it plays an important role in digital video compression. Because of its high computational complexity, however, it is difficult to apply to high-resolution applications in real time environments. If we have information about the motion of an image block before the motion estimation, the location of a better starting point for the search of an exact motion vector can be determined to expedite the searching process. In this paper, we present an adaptive motion estimation approach bated on temporal correlations of consecutive image frames that defines the search pattern and determines the location of the initial search point adaptively. Through experiments, compared with DS(Diamond Search) algorithm, the proposed algorithm is about 0.1∼0.5(dB) better than DS in terms of PSNR(Peak Signal to Noise Ratio) and improves as high as 50% compared with DS in terms of average number of search point per motion vector estimation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.149-159
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• 2001

The conventional block-based motion prediction suffers, especially in low bit-rate video application, from shortcomings such as blocking artifacts of motion field and unstable motion estimation. To overcome the deficiency, this paper proposes one method of adopting a new motion compensation scheme based on the irregular triangular mesh structure while keeping the current block-based DCT coding structure of H.263 as much as possible. To represent the reconstructed previous frame using minimal number of control points, the proposed method designs content-adaptive irregular triangular meshes, and then, estimate the motion vector of each control point using the affine transformation-based matching. The predicted current frame is obtained by applying the affine transformation to each triangular mesh. Experiment with the several real video sequences shows improvement both in objective and subjective picture quality over the conventional block-based H.263 method.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.342-348
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• 2013

In this paper, a novel frame rate up conversion (FRUC) algorithm using adaptive extended bilateral motion estimation (AEBME) is proposed. Conventionally, extended bilateral motion estimation (EBME) conducts dual motion estimation (ME) processes on the same region, therefore involves high complexity. However, in this proposed scheme, a novel block type matching procedure is suggested to accelerate the ME procedure. We calculate the edge information using sobel mask, and the calculated edge information is used in block type matching procedure. Based on the block type matching, decision will be made whether to use EBME. Motion vector smoothing (MVS) is adopted to detect outliers and correct outliers in the motion vector field. Finally, overlapped block motion compensation (OBMC) and motion compensated frame interpolation (MCFI) are adopted to interpolate the intermediate frame in which OBMC is employed adaptively based on frame motion activity. Experimental results show that this proposed algorithm has outstanding performance and fast computation comparing with EBME.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.6 s.312
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• pp.57-64
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• 2006

Motion estimation plays an important role for the compression of video signals. The proposed method utilizes an adaptive threshold and characteristics of a distribution of SAD (sum of absolute difference). Generally, the more complex the SAD distribution is, the larger SAD value tends to be. This proposed algorithm tries to reduce the search points in a simple distribution but increase them in a complex distribution to avoid local minima. A macro block is divided into 9 areas. One of them chosen using spatio-temporal correlation is called the primary area and the others are called the secondary area that will be searched to avoid local minima. The proposed algorithm decides if just one area (the primary area or the secondary area) will be enough to be searched or both areas should be searched, using adaptive threshold. Compared with famous motion estimation algorithms, the simulation result shows that the searching points per macro block and MSE decreases about 16.4% and 32.83 respectively on the average.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.129-133
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• 2015

In this paper, we propose a fast motion estimation algorithm which is important in the performance of video encoding. Conventional fast motion estimation algorithms have serious problems of low prediction quality in some frames and still much computation. In the paper, we propose an algorithm that reduces unnecessary computations only, while keeping prediction quality almost similar to that of the full search. The proposed algorithm uses distribution of probability of motion vectors, divides search range into several groups according to its importance, and applies adaptive block matching criteria for each group of search range. The proposed algorithm takes only 3~5% in computational amount and has decreased prediction quality about 0~0.01dB compared with the fast full search algorithm.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.9-18
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• 2016

This paper proposes a multi-view Wyner-Ziv Video coding scheme based on spatio-temporal adaptive estimation. The proposed algorithm is designed to search for a better estimated block with joint bi-directional motion estimation by introducing weights between temporal and spatial directions, and by classifying effectively the region of interest blocks, which is based on the edge detection and the synthesis, and by selecting the reference estimation block from the effective motion vector analysis. The proposed algorithm exploits the information of a single frame viewpoint and adjacent frame viewpoints, simultaneously and then generates adaptively side information in a variety of closure, and reflection regions to have a better performance. Through several simulations with multi-view video sequences, it is shown that the proposed algorithm performs visual quality improvement as well as bit-rate reduction, compared to the conventional methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.522-523
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• 2015

본 논문에서는 FRUC(Frame Rate Up-Conversion)을 위한 효과적인 관심영역 분리 방법을 제안한다. 기존의 알고리듬은 움직임 벡터를 이용하여 관심영역을 지정하고 이를 기반으로 추가적인 재탐색이 요구되며 경우에 따라 잘못 예측된 움직임 벡터가 사용됨으로 인해 관심영역에 대한 신뢰성이 낮다. 본 논문에서는 이전과 다음 영상과의 시간적 연관성을 이용하여 이 두 영상간의 상관관계에 따라 효과적으로 신뢰영역 및 관심영역을 분리한다. 본 논문에서는 기존에 제안되었던 알고리듬으로 생성된 보조 영상과 원본 영상과의 차이에 대해 제안한 관심영역 분리 방법을 적용하여 그 결과를 비교하고, 성능 척도로서 객관적 화질을 비교한다. 실험 결과를 통해 기존에 제시된 다수의 알고리듬 보다 비교적 간단한 방법을 통해 효과적으로 관심 영역을 분리하고 또한, 성능이 크게 향상될 수 있음을 보인다.