• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.861-872
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• 2011

Many fast block-matching algorithms (BMAs) in motion estimation field reduce computational complexity by screening the number of checking points. Although many fast BMAs reduce computations, sometimes they should endure matching errors in comparison with full-search algorithm (FSA). In this paper, a novel fast BMA for constrained one-bit transform (C1BT)-based motion estimation is proposed in order to decrease the calculations of the block distortion measure. Unlike the classical fast BMAs, the proposed algorithm shows a new approach to reduce computations. It utilizes the binomial distribution based on the characteristic of binary plane which is composed of only two elements: 0 and 1. Experimental results show that the proposed algorithm keeps its peak signal-to-noise ratio (PSNR) performance very close to the FSA-C1BT while the computation complexity is reduced considerably.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1506-1517
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• 1999

In this paper, we propose two fast block matching algorithm using the distribution of mean absolute difference (MAD) at the search region overlapped with neighbor blocks and pixel subsapmling. The proposed methods use the lower and upper bound of MAD at the overlapped search region which is calculated from the MAD of neighbor block at that search position and MAD between the current block and neighbor block. In the first algorithm, we can reduce the computational complexity by executing the block matching operation at the only necessary search points. That points are selected using the lower bound of MAD. In the second algorithm, we use the statictical distribution of actual MAD which exists between the lower bound and upper bound of MAD. By using the statistical distribution of actual MAD, we can significantly reduce the computational complexity for motion estimation. after striking space key 2 times.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1531-1536
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• 2016

In this paper, we propose a fast motion estimation algorithm which is important in performance of video encoding. Even though so many fast algorithms for motion estimation have been published due to its tremendous computational amount of for full search algorithm, efforts for reducing computations in motion estimation still remain. In the paper, we propose an algorithm that reduces unnecessary computations only, while keeping prediction quality the same as that of the full search. The proposed algorithm does not calculate block matching error for each candidate at once to find motion vectors but divides the calculation procedure into several steps and calculates partial sum of block errors. By doing that, we can estimate the minimum error point early and get the enhancement of calculation speed by reducing unnecessary computations. The proposed algorithm uses smaller computations than conventional fast search algorithms with the same prediction quality as full search.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.77-85
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• 2006

There is the spatial correlation of the video sequence between the motion vector of current blocks. In this paper, we propose the enhanced fast block matching algorithm using the spatial correlation of the video sequence and the center-biased properly of motion vectors. The proposed algorithm determines an exact motion vector using the predicted motion vector from the adjacent macro blocks of the current frame and the Cross-Hexagonal search pattern. From the of experimental results, we can see that our proposed algorithm outperforms both the prediction search algorithm (NNS) and the fast block matching algorithm (CHS) in terms of the search speed and the coded video's quality. Using our algorithm, we can improve the search speed by up to $0.1{\sim}38%$ and also diminish the PSNR (Peak Signal Noise Ratio) by at nst $0.05{\sim}2.5dB$, thereby improving the video qualify.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.293-302
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• 2004

Wireless LAN is a rather mature communication technology that connects mobile terminals. A typical wireless LAN system is composed of one AP and more than one terminals, which is called a BSS. Terminals near to an AP can receive high rate data but terminals far from an AP may not receive data with guaranteed high speed rate because received signal strength is weakened. This paper proposes a method to allow high speed data transmission by grouping terminals and using part of wireless terminals as repeaters. We compare and analyze proposed grouping algorithms based on Depth First Search and Breadth First Search via simulations. A grouping algorithm based on Breadth First Search is shown to be more effective in term of efficiency and coverage.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1759-1760
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• 2006

GPS 수신기에서 항법을 수행하기 위해서 신호탐색, 신호추적, 데이터 동기, 데이터 복조, 측정치 생성 및 위치 계산의 과정을 거쳐야 한다. TTFF(Time To First Fix)는 이러한 시간의 합으로 수신기의 성능을 나타내는 중요 평가지수 중의 하나이다. 일반적인 수신기의 TTFF는 80~90초인 것으로 알려져 있으며, 고속으로 운동하는 항체의 경우, 빠른 TTFF를 필요로 하므로 가장 긴 시간이 소비하는 신호탐색 과정의 시간을 줄여야 한다. 본 논문에서는 고속으로 운동하는 항체에서 GPS 신호의 코드 탐색 시간을 줄이기 위하여 다중 상관기 구조를 가지는 수신기를 설계 하고자한다. 설계한 수신기는 수신된 신호의 코드위상을 여러 개의 상관기에서 동시에 탐색하도록 다중 상관기를 구성하여 코드위상 검색에 소요되는 시간을 단축시킨다. 이를 검증하기 위하여 GPS 모의 신호 발생기를 이용하여 실험을 수행하였다. GPS 신호는 IF 데이터 수집 장치로부터 수집된 신호를 이용하며, 실험 수행 결과 다중 상관기를 이용하였을 때 TTFF가 단축되는 것을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1392-1400
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• 1999

In this paper, we propose a two-stage fast full search algorithm for block motion estimation that produces the same performance to that of full search algorithm (FSA) but with remarkable computation reduction. The proposed algorithm uses the search region subsampling and the difference of adjacent pixels in the current block. In the first stage, we subsample the search region by a factor of 9, and then calculate mean absolute error (MAE) at the subsampled search points. And in the second stage, we reduce the search points that need block matching process by using the lower bound of MAE value at each search Point. We Set the lower bound of MAE value for each search point from the MAE values which are calculated at the first stage and the difference of adjacent pixels in the current block. The experimental results show that we can reduce the computational complexity considerably without any degradation of picture quality.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.418-423
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• 2004

The motion estimation algorithm based block matching is a widely used in the international standards related to video compression, such as the MPEG series and H.26x series. Full search algorithm(FA) ones of this block matching algorithms is usually impractical because of the large number of computations required for large search region. Fast search algorithms and conventional binary block matching algorithms reduce computational complexity and data processing time but this algorithms have disadvantages that is less performance than full search algorithm. This paper presents new Boolean matching algorithm, called BCBM(Bit Converted Boolean Matching). Proposed algorithm has performance closed to the FA by Boolean only block matching that may be very efficiently implemented in hardware for real time video communication. Simulation results show that the PSNR of the proposed algorithm is about 0.08㏈ loss than FA but is about 0.96∼2.02㏈ gain than fast search algorithm and conventional Boolean matching algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.126-131
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• 2004

Full search algorithm(FA) provides the best performance but this is usually impractical because of the large number of computations required for large search region. Fast search and conventional Boolean matching algorithms reduce computational complexity and data processing time but this algorithms have disadvantages that is difficult of implementation of hardware because of high control overhead and that is less performance than FA. This paper presents new Boolean matching algorithm, called BCBM(Bit Converted Boolean Matching). Proposed algorithm has performance closed to the FA by Boolean only block matching that may be very efficiently implemented in hardware for real time video communication. Simulation results show that the PSNR of the proposed algorithm is about 0.08㏈ loss than FA but is about 0.96∼2.02㏈ gain than fast search algorithm and conventional Boolean matching algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.174-175
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• 2013

HEVC의 화면내 예측 부호화는 예측 모드를 최대 35개까지 확장함으로써 기존H.264/AVC에 비해서 향상된 부호화 효율을 갖는다. 반면 화면내 부호화의 복잡도 또한 크게 증가하여 복잡도 감소를 위한 고속 부호화 기법이 요구된다. HEVC의 차조모델인 HM에서는 화면내 부호화 고속화를 위해 RMD(Rough Mode Decision) 과정을 통하여 후보 모드를 결정하고 선택된 후보 모드에서 초종 예측 모드를 결정한다. 본 논문에서는 화면내 부호화의 복잡도 감소를 위하여 고속 화면내 예측 모드 결정 기법을 제시한다. 본 기법은 후보 모드를 결정하기 위한 RMD 과정에서의 탐색 모드 수와후보 모드로부터 최종 모드를 결정하기 위한 탐색 모드 수를 제한하는 방법을 결합하여 모드 결정을 위한 복잡도를 감소한다. 본 제안 기법은 실험결과 HM 12.0대비 1.0%의 비트 증가로 13.19%의 복잡도를 감소시킬 수 있었다.