• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.147-150
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• 2000

본 논문은 무인감시 시스템의 특성상 조명 상태의 변화나 카메라의 흔들림과 같은 환경의 변화에 적응할 수 있도록 연속된 세 프레임간의 차영상를 이용하는 방법을 적용하여 움직임 정보를 추출하고, 영역의 분할 및 특징점 추출을 수행한 후에, 인공 신경회로망 기법을 적용하여 이동표적을 추적한다. 추적시에는 추출된 각각의 표적간의 데이터 연결을 움직임 정보의 특징점들을 이용, 레이블링하여 각각의 표적을 연결시켜 추적의 성능을 높였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1187-1193
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• 2014

This paper presents an effective motion estimation to improve the performance of the motion compensated temporal filtering (MCTF) which is a core part of the wavelet-based scalable video coding. The proposed scheme makes the motion vector field uniform by the modified median operation and the search strategies using adjacent motion vectors, in order to enhance the pixel connectivity which is significantly relevant to the performance of the MCTF. Moreover, the motion estimation with variable block sizes that reflects the features of frames is introduced for further correlation improvement of the motion vector field. Experimental results illustrate that the proposed method reduces the decomposed energy on the temporal high frequency subband frame up to 30.33% in terms of variance compared to the case of the full search with fixed block sizes.

• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.37-44
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• 2002

In this paper. we propose a new video coding scheme with multi-resolution motion compensation and residual quantization. The main functional blocks of the proposed scheme include multi-level wavelet decomposition. motion estimation and motion compensation. raster scanning within each subband. formation of block trees and blocking partitioning. and adaptive arithmetic coding. Although the proposed ceding scheme is simple and requires low computational complexity, it produces bitstreams tilth good features. such as the embedded structure and SNR scalability. Experimental results demonstrate that the proposed coding scheme is quote competitive to and often outperforms other wavelet-based video coding schemes in the literature.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.3
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• pp.18-27
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• 2009

In this paper, we propose a frame rate conversion algorithm using adaptive search-based motion estimation (ME). The proposed ME method uses recursive search, 3-step search, and single predicted search as candidates for search strategy. The best method among the three candidates is adaptively selected on a block basis according to the predicted motion type. The adaptation of the search method improves the accuracy of the estimated motion vectors while curbing the increase of computational load. To support the proposed ME method, an entire image is divided into three regions with different motion types. Experimental results show that the proposed FRC method achieves better image quality than existing algorithms in both subjective and objective measures.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.163-168
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• 2003

In transmitting compressed video bit-stream over Internet, packet loss causes error propagation in both spatial and temporal domain, which in turn leads to severe degradation in image quality. In this paper, a new approach for the recovery of lost or erroneous Motion Vector(MV)s by classifying the movements of neighboring blocks by their homogeneity is proposed. MVs of neighboring blocks are classified according to the direction of MVs and a representative value for each class is determined to obtain the candidate MV set. By computing the distortion of the candidates, a MV with the minimum distortion is selected. Experimental results show that the proposed algorithm exhibits better performance in many cases than existing methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.75-78
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• 2004

H.264/AVC 동영상 부호화 표준은 이전의 여러 동영상 부호화 표준에는 없던 새로운 부호화 도구들이 추가되었으며 이를 통하여 보다 높은 압축 효율을 보인다. 추가된 부호화 도구들로 인하여 H.264내의 매크로블록은 이전의 부호화 표준에서 보다 많은 정보를 포함한다. 하나의 매크로블록에 대해서 최대 16개까지의 서로 다른 움직임벡터를 가질 수 있으며 최대 4개의 서로 다른 참조프레임을 가질 수 있다. 또한 다양한 블록크기로의 움직임 추정하며 이는 매크로블록의 모드로서 정의된다. 따라서 H.264내의 매크로블록은 기존보다 많은 움직임벡터를 가질 뿐만 아니라 기존에는 없던 참조 프레임과 매크로블록모드의 정보를 새로이 포함하고 있다. 반면 현재의 H.264내의 시방향 에러은닉기법은 이전 부호화 표준에서 사용하던 방법과 유사한 방법으로 에러가 발생한 블록의 주변 매크로블록의 움직임 벡터만을 고려하여 에러를 은닉한다. 본 논문은 H.264 부호화 표준의 특성을 고려하여 매크로블록이 포함하고 있는 다양한 의기의 움직임벡터 및 참조 프레임 뿐 아니라 주변 매크로블록들의 모드를 이용하여 서로 다른 블록 크기로 에러를 은닉함으로써 매크로블록이 포함하고 있는 정보를 최대한 활용하고 이를 통한 효율적인 에러은닉 알고리듬을 제안한다. 제안하는 알고리듬은 기존의 H.264에서의 시방향 에러은닉 기법과 비교하여 적은 연산량만을 가지면서도 최대 2.17dB까지의 향상된 화질을 나타낸다.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.699-712
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• 2014

In this paper, we propose a new Adaptive Search Range (ASR) decision algorithm for accelerating GPU-based Integer-pel Motion Estimation (IME) of High Efficiency Video Coding (HEVC). For deciding the ASR, we classify a frame into two models using Motion Vector Differences (MVDs) then adaptively decide the search ranges of each model. In order to apply the proposed algorithm to the GPU-based ME process, starting points of the ME are decided using only temporal Motion Vectors (MVs). The CPU decides the ASR as well as the starting points and transfers them to the GPU. Then, the GPU performs the integer-pel ME. The proposed algorithm reduces the total encoding time by 37.9% with BD-rate increase of 1.1% and yields 951.2 times faster ME against the CPU-based anchor. In addition, the proposed algorithm achieves the time reduction of 57.5% in the ME running time with the negligible coding loss of 0.6%, compared with the simple GPU-based ME without ASR decision.

• Journal of Korea Multimedia Society
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• v.10 no.11
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• pp.1427-1438
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• 2007

Video watermarking technologies are classified into types of four kinds. The first type is to embed the watermark into a raw video signal and to code the watermarked video signal. Most of video watermarking technologies fall into the category of this type. The second type is to apply watermarking to the coding process, such as block DCT and quantization. The third is to directly embed the watermark into the compressed bitstream itself. Generally, it is referred as labelling rather than watermarking. Finally, the fourth is to embed the water mark into MPEG motion vector. This type has the difficulty in real-time process because of the high complexity and has the blocking effects because of DCT-based on coder. In this paper, we proposed the digital video watermarking that embed the watermark in SPIHT video code for I-frame using motion vector analysis. This method can remove the blocking effect occurred at the DCT-based on coder and obtain video data that has progressive transmission property. The proposed method is to select the region for the watermark embedding in I frame using motion vector estimated from the previous P or B frame. And then, it is to perform DWT and embed the watermark based on HVS into the wavelet coefficients in the same subband of DWT as the motion vector direction. Finally, the watermarked video bitstream is obtained by the SPIHT coder. The experimental results verified that the proposed method has the invisibility from the objective and subjective image quality and the robustness against the various SPIHT compression and MPEG re-code.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.223-236
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• 2012

We develop a video processing method that allows the more advanced human perception oriented video coding. The proposed method necessarily reflects all influences by the rate-distortion based optimization and the human visual perception that is affected by the visual saliency, the limited space-time resolution and the regional moving history. For reflecting the human perceptual effects, we devise an online moving pattern classifier using the Hedge algorithm. Then, we embed the existing visual saliency into the proposed moving patterns so as to establish a human visual perception model. In order to realize the proposed human visual perception model, we extend the conventional foveation filtering method. Compared to the conventional foveation filter only smoothing less stimulus video signals, the developed foveation filter can locally smooth and enhance signals according to the human visual perception without causing any artifacts. Due to signal enhancement, the developed foveation filter more efficiently transfers the bandwidth saved at smoothed signals to the enhanced signals. Performance evaluation verifies that the proposed video processing method satisfies the overall video quality, while improving the perceptual quality by 12%~44%.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.255-262
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• 2012

Human motion tracking algorithm is receiving attention from many research areas, such as human computer interaction, video conference, surveillance analysis, and game or entertainment applications. Over the last decade, various tracking technologies for each application have been demonstrated and refined among them such of real time computer vision and image processing, advanced man-machine interface, and so on. In this paper, we introduce cost-effective and real-time human motion tracking algorithms based on depth image 3D point matching with a given superellipsoid body representation. The body representative model is made by using parametric volume modeling method based on superellipsoid and consists of 18 articulated joints. For more accurate estimation, we exploit initial inverse kinematic solution with classified body parts' information, and then, the initial pose is modified to more accurate pose by using 3D point matching algorithm.