• 대기
• /
• 제25권3호
• /
• pp.511-520
• /
• 2015

Existing studies on radar rainfall uncertainties were performed to reduce the uncertainty for each stage by using bias correction during the quantitative radar rainfall estimation process. However, the studies do not provide quantitative comparison with the uncertainties for all stages. Consequently, this study proposes a suitable approach that can quantify the uncertainties at each stage of the quantitative radar rainfall estimation process. First, the new approach can present initial and final uncertainties, increasing or decreasing the uncertainty, and the uncertainty percentage at each stage. Furthermore, Maximum Entropy (ME) was applied to quantify the uncertainty in the entire process. Second, for the uncertainty quantification of radar rainfall estimation at each stage, this study used two quality control algorithms, two rainfall estimation relations, and two bias correction techniques as post-processing and progressed through all stages of the radar rainfall estimation. For the proposed approach, the final uncertainty (ME = 3.81) from the ME of the bias correction stage was the smallest while the uncertainty of the rainfall estimation stage was higher because of the use of an unsuitable relation. Additionally, the ME of the quality control was at 4.28 (112.34%), while that of the rainfall estimation was at 4.53 (118.90%), and that of the bias correction at 3.81 (100%). However, this study also determined that selecting the appropriate method for each stage would gradually reduce the uncertainty at each stage. Finally, the uncertainty due to natural variability was 93.70% of the final uncertainty. Thus, the results indicate that this new approach can contribute significantly to the field of uncertainty estimation and help with estimating more accurate radar rainfall.

• 전자공학회논문지
• /
• 제52권6호
• /
• pp.62-69
• /
• 2015

본 논문에서는 움직임 추정 기법을 적응적으로 사용하는 프레임율 증강 기법인 AME-FRUC (Adaptive Motion Estimation Frame Rate Up-Conversion)을 제안하고자 한다. 제안하는 알고리즘은 영상의 움직임이 적은 영역에서 기존의 EBME (Extended Bilateral Motion Estimation)을 활용하고, 움직임 벡터 정보를 활용하여 관심영역을 결정한다. 관심 영역에서는 제안하는 텍스쳐 정보에 기반한 블록 분할을 활용한 단방향 움직임 추정을 수행하도록 하여 정확도를 높였다. 최종적으로 MCFI (Motion Compensated Frame Interpolation)기법을 움직임 추정 방법에 따라 적용하고 보간 하여 중간 프레임을 생성 한다. 실험 결과를 통해 제안하는 알고리즘이 기존의 FRUC 알고리즘에 비해 최대 68% 적은 SAD 연산으로 3dB 높은 PSNR 성능과 0.07 더 높은 SSIM 성능을 보이는 것을 확인할 수 있다.

• ETRI Journal
• /
• 제36권4호
• /
• pp.528-536
• /
• 2014

High Efficiency Video Coding (HEVC) is the most recent video coding standard to achieve a higher coding performance than the previous H.264/AVC. In order to accomplish this improved coding performance, HEVC adopted several advanced coding tools; however, these cause heavy computational complexity. Similar to previous video coding standards, motion estimation (ME) of HEVC requires the most computational complexity; this is because ME is conducted for three inter prediction modes - namely, uniprediction in list 0, uniprediction in list 1, and biprediction. In this paper, we propose an efficient inter prediction mode (EIPM) decision method to reduce the complexity of ME. The proposed EIPM method computes the priority of all inter prediction modes and performs ME only on a selected inter prediction mode. Experimental results show that the proposed method reduces computational complexity arising from ME by up to 51.76% and achieves near similar coding performance compared to HEVC test model version 10.1.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.749-752
• /
• 2008

Various Motion Estimation (ME) algorithms have been proposed since ME requires large computational complexity. The proposed algorithm employs Enhanced Cross Search Pattern (ECSP) using motion vector of neighbor-blocks to search the motion vector. The experimental results show that proposed algorithm reduces the search point up to 35% compared to conventional methods.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.38-40
• /
• 2007

In this paper, we propose a novel architecture, which is based on DCT (Discrete Cosine Transform), for ME (Motion Estimation) and MC (Motion Compensation). The traditional algorithms of ME and MC based on DCT did not suffer the advantage of the coarseness of the 2-dimensional DCT (2-D DCT) coefficients to reduce the operational time. Therefore, we derive a recursion equation for transform-domain ME and MC and design the structure by using highly regular, parallel, and pipeline processing elements. The main difference with others is removing the IDCT block by using to transform domain. Therefore, the performance of our algorithm is more efficient in practical image processing such as DVR (Digital Video Recorder) system. We present the simulation result which is compare with the spatial domain methods. it shows reducing the calculation cost. compression ratio. and peak signal to noise ratio (PSNR).

• 정보통신설비학회논문지
• /
• 제10권2호
• /
• pp.53-61
• /
• 2011

This research presents an adaptive fast motion estimation (ME) computation on the stage of uneven multi-hexagon grid search (UMHGS) algorithm included in an unsymmetrical-cross multi-hexagon-grid search (UMHexagonS) in H.264 standard. The proposed adaptive method is based on statistical analysis and previously obtained motion vectors to reduce the computational complexity of ME. For this purpose, the algorithm is decomposed into three processes: skipping, terminating, and reducing search areas. Skipping and terminating are determined by the statistical analysis of the collected minimum SAD (sum of absolute difference) and the search area is constrained by the slope of previously obtained motion vectors. Simulation results show that 13%-23% of ME time can be reduced compared with UMHexagonS, while still maintaining a reasonable PSNR (peak signal-to-noise ratio) and average bitrates.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -2
• /
• pp.807-810
• /
• 2000

In this paper, a new hierarchical motion estimation (ME) scheme using the wavelet transformed multi-resolution image layers is proposed. While the coarse-to-fine (CtF) ME, used in previously proposed coding schemes, can provide a better estimate at the coarsest resolution, it is difficult to accurately track motion at finer resolution. On the other hand, in fine-to-coarse (FtC) ME, it can solves this local minima problem by estimating motion track at the finest subband and propagating the motion vector (MV) to coarser subband. But this method causes to higher computational overhead. This paper proposes a new method for reducing the computational overhead of fine-to-coarse rnulti-resolution motion estimation (MRME) at the finest resolution level by searching for the region to consider motion vectors of the coarsest resolution subband.

• 방송공학회논문지
• /
• 제8권3호
• /
• pp.288-296
• /
• 2003

ATSC (Advanced Television System Committee)에서는 18가지의 DTV (Digital Television)를 위한 동영상 포맷들을 제정하였다. ATSC 포맷들은 스캔 포맷, 크기 포맷, 프레임율 포맷 등의 적당한 조합들이다. 효과적인 MPEG-2 트랜스코딩을 위해서는 이런 포맷들 간의 변환도 지원할 수 있어야 한다. 여러 포맷 변환들 중에서 특히 스캔 포맷 변환은 프레임율과 크기 변화가 함께 일어나기 때문에 상대적으로 구현하기가 힘들다. 스캔포맷 변환으로 픽쳐 타입도 함께 변하기 때문에 트랜스코더의 움직임 추정부 (motion estimation; ME)에 상당한 연산량 부담을 주게 된다. 이런 문제를 해결하기 위해 본 논문은 스캔포맷 변환을 지원하는 MPEG-2 동영상 트랜스코딩을 위한 고속 움직임 추정 알고리즘을 제안한다. 먼저, 트랜스코더의 수신단은 입력 비트열로부터 재 부호화(re-encoding)에 적합한 후보 움직임 벡터들을 추출한다. 그런 다음. 가중치 중간값 선택기(weighted median selector)를 이용하여, 여러 후보 움직임 벡터들 중에서 최적의 움직임 벡터를 선택한다. 모의 실험 결과는 제안한 움직임 추정 알고리즘이 전역 탐색 기법(Full Search Algorithm: FSA)에 비해 현저하게 적은 연산량을 가지면서, FSA와 거의 동일한 PSNR 성능을 가짐을 증명한다.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.381-384
• /
• 2009

In the Wyner-Ziv coding, compression performance highly depends on the quality of the side information since better quality of side information brings less channel noise and less parity bit. However, as decoder generates side information without any knowledge of the current Wyner-Ziv frame, it doesn't have optimal criterion to decide which block is more advantageous to generate better side information. Hence, in general, fixed block size motion estimation (ME) is performed in generating side information. By the fixed block size ME, the best coding performance cannot be attained since some blocks are better to be motion estimated in different block sizes. Therefore if there is a way to find appropriate ME block of each block, the quality of the side information might be improved. In this paper, we investigate the effects of variable block sizes of ME in generating side information.

• 대한전자공학회논문지SP
• /
• 제46권4호
• /
• pp.108-115
• /
• 2009

본 논문에서는 에러에 강인한 동영상 압축을 위해서 효과적인 에러 은닉을 제공하는 새로운 움직임 예측기법을 제안한다. 일반적으로 전송 에러에 의해 손실된 프레임을 효율적으로 복원하기 위해서는 영상 내에서 객체의 실제 움직임을 정확하게 아는 것이 중요하다. 하지만 현재 블록과 움직임 보상된 블록에 있는 화소의 차의 절대값의 합 (sum of absolute different, SAD)을 기준으로 이용하는 기존의 움직임 예측 (motion estimation, ME)기법이 객체의 실제 움직임을 항상 정확하게 반영하는 것은 아니다. 이러한 문제를 해결하기 위해서, 본 논문에서 현재 블록과 움직임 보상된 블록의 움직임 벡터들의 차이의 절대값 (absolute different of motion vectors, ADMV)을 새로운 부가적인 기준으로 소개한다. 본 논문에서 제안하는 ME 기법은 SAD와 ADMV의 가중 합을 최소화시킴으로써 실제 움직임과 거리가 먼 움직임 벡터들을 효과적으로 제거할 수 있다. 또한, 제안하는 ADMV을 이용하면 영상의 전송 과정에서 손실된 프레임의 정보를 전혀 사용하지 않고도 손실된 움직임 정보를 효과적으로 복원할 수 있으므로 복호기에서의 에러 은닉 성능을 크게 향상시킬 수 있다. 실험을 통하여 본 논문에서 제안하는 기법이 기존의 ME기법과 유사한 압축 효율을 갖으면서 기존의 에러 내성 기법보다 성능이 더 우수하다는 것을 확인하였다.