• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.1058-1068
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• 2011

Video FRUC (Frame Rate Up Conversion) is one of the main issues that have arisen in recent years with the explosive growth of video sources and display formats in consumer electronics. Most advanced FRUC algorithms adopt an efficient motion interpolation technique to determine the motion vector field of interpolated frames. But, in some application areas such as post processing in receiver side, it is necessary to evaluate how well the MCI (Motion Compensated Interpolation) frame was reconstructed. In order to achieve this aim, first, this paper introduces some cost functions to estimate the reliability of a block in the MCI frame. Then, by using these functions, this paper proposes two distortion estimation models for evaluating how much noise was produced in the MCI frame. Through computer simulations, it is shown that the proposed estimation methods perform effectively in estimating the noises of the MCI frame.

• Journal of KIISE
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• v.41 no.11
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• pp.900-910
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of multi view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, improved prediction structure and motion estimation method is proposed in this paper. The proposed prediction structure exploits an average distance between the current picture and its reference pictures. The proposed prediction structure divides every GOP into several groups to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. And the proposed motion estimation method uses a hierarchical search strategy. This strategy method consists of modified diamond search pattern, progressive diamond search pattern and modified raster search pattern. Experiment results show that the complexity reduction of the proposed prediction structure and motion estimation method over JMVC (Joint Multiview Video Coding) reference model using hierarchical B pictures of Fraunhofer-HHI and TZ search method can be up to 40~70% while maintaining similar video quality and bit rates.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.259-261
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• 1999

본 논문은 MPEG-2 TM 5 video 부호기의 전체구조 및 처리과정을 기술한다. MPEG-2는 저장 매체, 통신, 방송 매체 등을 위한 동영상 압축이 표준이다. MPEG-2 압축 방법에는 공간적 압축과 시간적 압축 방법이 있다. 공간적 압축 방법에는 화면에서의 중복성을 줄이기 위한 표본화 주파수(4:4:4, 4:2:2, 4:2:0, format), DCT, scanning(zigzag 혹은 alternate scanning)과 quantization이 있고 시간적 압축 방법에는 움직임 예측(motion estimation)과 I, P, B-picture를 사용하는 방법이 있다. 본 논문에서는 MPEG-2 부호기의 핵심을 전체 구조, DPCM, MPEG bitstream syntax, MPEG-2 부호화 알고리즘, 움직임 예측, 움직임 벡터, rate control 그리고 가변길이 코딩(variable length coding)으로 구분하여 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.153-156
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• 2006

본 논문에서는 H.264 표준화 기구인 Joint Video Team(JVT) 권고안의 정수 단위 화소 움직임 예측을 위한 Unsymmetrical-cross Multi-Hexagon-grid Search(UMHexagonS) 알고리즘에서 Uneven Multi-Hexagon-grid Search(UMHGS) 부분을 개선한 알고리즘을 제안한다. 제안하는 알고리즘은 이전 프레임의 동일위치 또는 상위 모드에서 이미 선택된 움직임 벡터(MV: Motion Vector)를 이용하여 신호 대 잡음 비(PSNR: Peak Signal to Noise Ratio) 및 평균 비트 율(Average Bitrates)을 유지하면서, 현재 매크로블록의 검색영역을 줄이는 것이 가능하다. 제안하는 알고리즘의 성능은 Full Search Block Matching Algorithm(FSBMA) 및 UMHexagonS 알고리즘의 integer pel 에 대한 SAD(Sum of Absolute Difference) 연산횟수로 비교평가 하였다. 그 결과, FSBMA 에 비하여 평균 97.64%, UMHexagonS 에 비하여는 평균 17.48%의 연산횟수를 감소시키는 우수함을 보였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.204-206
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• 2016

본 논문에서는 template matching을 이용한 PMMVD(Pattern Matched Motion Vector Derivation)기술에 대해 움직임 추정 방식에 따라 복잡도를 분석한다. PMMVD 기술은 HEVC의 화면 간 예측 기술과는 다르게 움직임과 관련된 정보를 부호화하지 않으며, 복호화기에서 움직임 벡터를 추정하는 방식이다. 따라서 종래의 기술 대비 높은 효율이 발생하지만 복호화기의 복잡도는 급격히 증가하게 된다. 이러한 이유로 다양한 움직임 추정 방식에 따라 성능을 분석하여 최적의 조합을 찾는 것은 매우 중요한 이슈임을 알 수 있다. 이를 위하여 현재 JVET(Joint Video Exploration Team)에서 FVC(Future Video Coding)를 위해 발표한 참조 소프트웨이인 JEM 2.0(Joint Exploration Test Model 2)을 이용하여 실험을 수행하고 향후 연구 방향을 논의한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.973-976
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• 2007

본 논문에서는 영상 시퀀스 내의 흔들림을 제거하는 고속 알고리즘을 제안한다. 프레임 지터 제거에 관한 연구는 영상 취득과정에서 발생하는 손떨림에 의한 영향을 제거하거나 오래된 영화필름에서 녹화장치의 기구적인 문제로 인해 발생한 흔들림을 제거하기 위해 많이 연구되었다. 제안하는 알고리즘은 영상 프레임을 배경과 전경 영역으로 나누고 움직임 벡터를 이용하여 천역 움직임을 구한다. 전역 움직임을 구하는 과정에서 잘못된 움직임 예측이 발생할 가능성이 높은 블록을 사전에 제거하여 속도를 개선하였으며 알고리즘을 실제 영상에 적용하여 영상 프레임 정합됨을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2C
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• pp.110-120
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• 2003

In this paper, we propose a Multiresolution Motion Estimation(MRME) adapted to Low-Band-Shift(LBS) method in wavelet domain. To overcome shift-variant property on wavelet coefficients, the LBS was previously proposed. This method which is applied to reference frame in video coding technique, has superior performance in terms of rate-distortion characteristic. However, this method needs more memory and computational complexity. In this paper, The computational complexity of the proposed method(LBS-MRME) is about 15.6% of that of existing method at 3-level wavelet transform. And although it has about 7 times as much as existing method's motion vector since each subband has different motion vector, it decreases motion compensated prediction error by detailed motion estimation, and then has better efficient coding performance. The experimental results with the proposed method showed about 0.3∼11.6% improvement of MAD performance in case of lossless coding, and 0.3∼3.0㏈ improvement of PSNR performance at the same bit rate in case of lossy coding.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.3
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• pp.20-29
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• 2008

In this paper, we propose a do-interlacing algorithm using integral projection-based motion estimation considering Region Of Interest(ROI). The proposed motion estimation method finds the motion of the given ROI accurately with low computational cost. In order to incorporate the motion estimation in do-interlacing, an entire image is first segmented into multiple ROIs according to the temporally predicted block-wise motion types and spatial positions. Then, motion vectors of respective ROIs are obtained by the integral projection method. In this paper, totally five ROIs, one for the global motion and four for the local motions, are made, and therefore, five motion vectors are produced for each field. By using the estimated motion vectors, motion compensation is performed for increasing the vortical resolution of the converted frames. Finally, do-interlaced frames are obtained by effectively combining the results of motion compensation and stable intra-field do-interlacing according to the reliability of motion compensation. Experimental results show that the proposed algorithm provides better image quality than existing algorithms in both subjective and objective measures.

• Journal of Broadcast Engineering
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• v.23 no.3
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• pp.409-420
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• 2018

In this paper, we propose a Motion Vector-based Particle Filter(MVPF) for object tracking on bitstreams and a object tracking system using the MVPF. The MVPF uses motion vectors to both the transition and the observation models of a general particle filter to improve the accuracy while maintaining the number of particles. In the proposed object tracking system, the state of the target object can be predicted using the histogram of motion vectors extracted from the bitstream. In terms of precision, F-measure and IOU(Intersection Of Union), the proposed method is about 30%, 17%, and 17% better on average, respectively, in MPEG test sequences and VOT2013 sequences. Furthermore, When the tracking results are displayed in box form for subjective performance evaluation, the proposed method can track moving objects more robust than the conventional methods in all test sequences.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.6
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• pp.91-99
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• 2004

This paper proposed two transcodiing methods, which maintain the same spatio-temporal resolution and reduce a spatial resolution, to convert a H.264 video bitstream into an MPEG-4 video bitstream. When the H.264 video bitstream is transformed into the MPEG-4 video bitstream, the conversions between H.264 block types and MPEG-4 block types are performed by minimizing distortion and the ${\times}4$ block-based motion vector mapping is performed. The proposed two transcoding methods run 4.14～5.1 times as fast as the cascaded transcoding methods in MPEG-4 encoder side, while the PSNR (peak-signal-to ratio) is slightly degrade with maximum 0.3dB.