• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.457-459
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• 2004

본 논문은 움직임 벡터 재 산출 방법에 있어서 제한된 영역 내의 움직임 벡터 재 탐색 과정을 보다 효율적으로 운용함으로써 기존의 방법보다 빠르게 동작하는 크기조절 트랜스코딩 방법을 제안한다 기존의 크기조절 비디오 트랜스코딩은 크기 조절된 비디오의 정형화된 재 산출 과정을 통해 움직임 벡터를 구하고, 화질 열화의 최소화를 위해 재 산출된 움직임 벡터를 제한된 탐색 영역 내재 탐색을 통해 좀더 정확한 움직임 벡터를 구하는 방법을 사용한다 그러나 움직임 벡터 재 탐색과정은 않은 계산이 요구되어 속도 저하의 원인이 되며, 비디오의 특성에 따라 움직임 벡터 재 탐색 과정이 불필요한 경우가 발생한다. 따라서, 움직임이 없는 비디오에 대해서는 움직임 벡터 재탐색 과정을 수행하지 않음으로써 트랜스코딩 과정의 수행 속도를 개선하고, 움직임이 많은 프레임에 대해서는 움직임 벡터 재 탐색을 수행하여 화질 열화를 최소화하는 방법을 제안한다. 제안된 방법을 적용하였을 때. 움직임이 적은 비디오일수록 화질 열화 없이 트랜스코딩 속도가 약 15%의 향상된 성능을 얻었다.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.9-14
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• 2011

This paper presents a new fast motion estimation method where search ranges are determined by the probabilities of motion vector differences (MVDs), which is an adaptive/dynamic search range (ASR) method. The MVDs' distribution is investigated and its parameter is estimated by the maximum likelihood estimator. With the estimated distribution, we show that the search ranges can be efficiently restricted by a prefixed probability for MVDs. Experimental results showed that the performance of the proposed method is very similar to that of the full search algorithm in PSNR but it enables significant reduction in the computational complexity. In addition, they revealed that the proposed method determine the search ranges much more efficiently than the conventional ASR methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.209-212
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• 2013

본 논문에서 적응적 탐색 영역(Adaptive Search Range)을 이용하여 개선한 제한된 1비트 변환 알고리즘을 제안하였다. 이 변환은 전역 검색 알고리즘 (Full Search Algorithm)을 사용한다. 그러나 이것은 매우 많은 연산량과 복잡도를 가진다. 제안된 알고리즘에서는 각 블록의 탐색범위를 결정하기 위한 움직임 벡터 (Motion Vector)와 함께 제한된 1비트 변환 알고리즘의 제한된 마스크 (Constrained Mask)를 사용한다. 실험결과를 통해 제안된 알고리즘은 움직임 예측의 정확도에 대한 성능을 비슷하게 유지하면서 평균적으로 Search Point의 수를 84% 줄일 수 있음을 보여준다.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.185-195
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• 2010

In this paper, we propose an efficient inter and intra prediction algorithms for fast encoding of H.264/AVC. First, inter prediction mode decision method decides early using temporal/spatial correlation information and pixel direction information. Second, intra prediction mode decision method selects block size judging smoothness degree with inner/outer pixel value variation and decides prediction mode using representative pixel and reference pixel. Lastly, adaptive motion search region restriction sets search region using mode information of neighboring block and predicted motion vector. The experimental results show that proposed method can achieve about 18~53% reduction compared with the existing JM 14.1 in the encoding time. In RD performance, the proposed method does not cause significant PSNR value losses while increasing bitrates slightly.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.2007-2012
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• 2011

To reduce huge computation in the block matching, this paper proposes a fast block matching algorithm which limits search points in the search area. On the basis of two facts that most motion vectors are located in central part of search area and matching error is monotonic decreasing toward the best similar block, the proposed algorithm moves a matching pattern between steps by the one pixel, predicts the motion direction for the best similar block from similar blocks decided in previous steps, and limits movements of search points to ${\pm}45^{\circ}C$ on it. As a result, it could remove the needless search points and reduce the block matching computation. In comparison with the conventional similar algorithms, the proposed algorithm caused the trivial image degradation in images with fast motion but kept the equivalent image quality in images with normal motion, and it, meanwhile, reduced from about 20% to over 67% of the their block matching computation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.2
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• pp.20-28
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• 2003

Recently we need a faster and more accurate motion vector search algorithm for ASIC(Application Specific IC) or small systems. Block motion estimation using Full Search(FS) algorithm provides the best visual quality and PSNR, but it requires intensive computations. The previously proposed fast algorithms reduced the number of computations by limiting the number of searching locations. This is accomplished at the expense of less accuracy of motion estimation and gives rise to an appreciably higher SAD(Sum of Absolute Difference) for motion compensated images. In this paper we exploit the spatial correlation of motion vectors and present a fast motion estimation scheme which uses the predicted motion vector(PMV). The PMV scheme is more clear and simpler than the previously proposed algorithms which also use adjacent motion vectors. Simulation results with standard video sequences show that the PMV scheme is faster and more accurate than other algorithms such as Nearest-Neighbors Search(NNS) algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.49-55
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• 2007

To improved the multi-resolution fast hierarchical motion estimation by using de-interlacing algorithm that is effective in term of both performance and VLSI implementation, is proposed so as to cover large search area field-based as well as frame based image processing in SoC design. In this paper, we have simulated a various picture mode M=2 or M=3. As a results, the proposed algorithm achieved the motion estimation performance PSNR compare with the full search block matching algorithm, the average performance degradation reached to -0.7dB, which did not affect on the subjective quality of reconstructed images at all. And acquiring the more desirable to adopt design SoC for the fast hierarchical motion estimation, we exploit foreground and background search algorithm (FBSA) base on the dual arithmetic processor element(DAPE). It is possible to estimate the large search area motion displacement using a half of number PE in general operation methods. And the proposed architecture of MHME improve the VLSI design hardware through the proposed FBSA structure with DAPE to remove the local memory. The proposed FBSA which use bit array processing in search area can improve structure as like multiple processor array unit(MPAU).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.225-228
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• 2011

동영상을 고효율로 압축할 수 있는 중요한 기술 중의 하나가 움직임 추정 기술이다. 움직임 추정 기술에서 가장 널리 사용되는 탐색 방식과 정합오차를 판단하는 기준은 각각 전역 탐색(FS: Full Search)알고리듬과 Sum of Absolute Differences(SAD)이다. 하지만, FS와 SAD를 사용한 움직임 추정기술은 인코더 전체 계산량의 50%이상을 차지하게 된다. 무선 통신 및 인터넷 환경에서 사용되는 응용프로그램에 대해서는 많은 계산량이 실시간 전송을 어렵게 만든다. 이러한 이유로, 동영상 압축 기술에서 계산량을 줄이는 방법이 중요하게 되었다. 그 결과로, SAD대신 다른 정합 오차 기준을 사용하여 움직임 추정기술의 계산량을 줄이는 알고리듬들이 제안되었다. 본 논문에서는 계산량을 줄이면서 하드웨어 구현 시 많은 이점을 가진 1비트 변환 (One-bit Transform, 1BT)알고리듬과 1비트 변환의 성능을 향상시킨 제한된 1비트 변환(Constrained one-bit transform, C-1BT)을 소개하고 C-1BT방법에 있어서 기존 방식의 빠른 인코딩속도를 유지하면서 PSNR을 증가시키는 알고리듬을 제안한다. 제안하는 알고리듬에서는 기존 C-1BT에서 고정해서 사용한 파라미터 D값을 대신에 현재블록과 동일한 위치에 있는 참조영역의 블록과 그 주변블록의 움직임벡터 정보를 이용해서 블록의 움직임 정도를 판단하고, 블록단위로 D값을 적응적으로 결정한다. 실험결과는 제안하는 알고리듬이 기존의 알고리듬과 비교하여 평균 0.11dB PSNR 증가를 보여 준다.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.63-68
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• 2004

In this paper, we propose a method about the extraction of vehicle and tracking trajectory for moving vehicle tracking system in road. This system applied to the monitoring system of the traffic flow for ATMS(advanced traffic management system) of ITS(intelligent transport system). Also, this system can solve the problem of maintenance of loop sensor. And we detected vehicle using differential image analysis. Because of the road environment changes by real time. Therefore, the method to use background image is not suitable. And we used Kalman filter and innovation value and variable search area for vehicle tracking system. Previous method using fixed search area is sensitive to the moving trajectory and the speed of vehicle. Simulation results show that proposed method increases the possibility of traffic measurement more than fixed area traffic measurement system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.56-65
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• 2009

Stereoscopic images consist of the left image and the right image. Thus, stereoscopic images have much amounts of data than single image. Then an efficient image compression technique is needed, the DPCM-based predicted coding compression technique is used in most video coding standards. Motion and disparity estimation are needed to realize the predicted coding compression technique. Their performing algorithm is block matching algorithm used in most video coding standards. Full search algorithm is a base algorithm of block matching algorithm which finds an optimal block to compare the base block with every other block in the search area. This algorithm presents the best efficiency for finding optimal blocks, but it has very large computational loads. In this paper, we have proposed fast disparity estimation algorithm using motion and disparity vector information of the prior frame in stereo image coding. We can realize fast disparity vector estimation in order to reduce search area by taking advantage of global disparity vector and to decrease computational loads by limiting search points using motion vectors and disparity vectors of prior frame. Experimental results show that the proposed algorithm has better performance in the simple image sequence than complex image sequence. We conclude that the fast disparity vector estimation is possible in simple image sequences by reducing computational complexities.