• Journal of the Korea Computer Graphics Society
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• v.6 no.3
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• pp.35-40
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• 2000

There are two problems in H.26X compression technique. One is compressing time in encoding process and the other is degradation of the decoded video quality due to high compression rate. For transferring moving pictures in real-time, it is required to adopt massively high compression. In this case, there are a lot of losses of an original video data and that results in degradation of quality. Especially degradation called by blocking artifact may be produced. The blocking artifact effect is produced by DCT-based coding techniques because they operate without considering correlation between pixels in block boundaries. So it represents discontinuity between adjacent blocks. This paper describes methods of quality compensation for H.26x decoded data and enhancing encoding speed for real-time operation. Our goal of the quality compensation is not to make the decoded video identical to a original video but to make it perceived better through human eyes. We suggest an algorithm that reduces block artifact and clears decoded video in decoder. To enhance encoding speed, we adopt new four-step search algorithm. As shown in the experimental result, the quality compensation provides better video quality because of reducing blocking artifact. And then new four-step search algorithm with $MMX^{TM}$ implementation improves encoding speed from 2.5 fps to 17 fps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.746-752
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• 2012

SVC layered video is consists of a Base Layer (BL) and Enhancement Layer (EL). Without the base layer decoding, the higher EL layer can not be decoded. Therefore, successful transfer of the BL is important factor for improving the SVC video data. In this paper, we propose a network coding of layered video to improve success decoding probability with the importance order of the video data over a multi-relay system. We shows that formula analysis and experimental results of the proposed network coding scheme. In addition, we shows performance of video quality according to the number of relays.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.119-127
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• 2008

Transmission of video over Internet or wireless network requires coded stream capable of adapting to dynamic network conditions instantly. To meet this requirement, various scalable video coding schemes have been developed, among which the Scalable Video Coding (SVC) extension of the H.264/AVC is the most recent one. In comparison with the scalable profiles of previous video coding standards, the SVC achieves significant improvement on coding efficiency performance. For adapting to dynamic network bandwidth, the SVC employs inter-layer switching between different temporal, spatial or/and fidelity layers, which is currently supported with instantaneous decoding refresh (IDR) access unit. However, for real-time adaptability, the SVC has to frequently employ the IDR picture, which dramatically decreases the coding efficiency. Therefore, an extension of SP picture from the AVC to the SVC for an efficient inter-layer switching is investigated and presented in this paper. Simulations regarding the adaptability to dynamic network bandwidth are implemented. Results of experiment show that the SP picture added SVC provides an average 1.2 dB PSNR enhancement over the current SVC while providing similar adaptive functionality.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.887-890
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• 2001

레이어 코딩된 비디오의 경우 Base 스트림과 Enhancement 스트림으로 나누어지게 되는데 중요한 정보인 Base 스트림을 보장하고 Enhancement 스트림의 손실을 최소화 하는 방법의 연구가 많이 진행되어 왔다. 인터넷 망은 이러한 비디오 정보를 전송할 때 패킷의 크기와 전송간격, 그리고 프로토콜에 다양하게 영향을 받는다. 본 논문에서는 트래픽의 상당량을 차지하는 비디오를 레이어 코딩을 사용할 경우 생기는 트래픽 특성과 클라이언트의 네트워크변화에 따른 상황을 분석하고 패킷의 전송 방법을 프로토콜별로 효율성을 분석하며 Base 스트림의 Guaranteed 서비스를 보장하기 위해 TCP 스트리밍 방법을 제안한다.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.477-480
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• 2003

This paper describes a novel method for image contrast enhancement by controlling gamma curve in AMLCD. The key idea is to automatically manipulate gamma voltage in accordance with the image data distribution. This method is applied to 17" SXGA LCD monitor module. The contrast ratio and the brightness are enhanced respectively by about 3 times and 1.7 times, by using the proposed method.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.465-467
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• 1998

MPEG-2 는 Layered Coding방식을 채택하여 하나의 base layer와 4개의 enhancement layer로 이루어져 있으나 동영상 재생을 위해 필요한 최소한의 layer인 base layer 만으로도 데이터 양이 많기 때문에 인터넷 환경에 적용하기가 어렵다. 이에 base layer를 다시 세분화된 layer로 나누기 위해 인코딩 중에는 또는 인코딩 결과로 만들어지는 MPEG-2 Video steam 의 하부 구조인 블록층에 존재하는 8$\times$8블록의 AC 계수들을 layering한다. Layered된 base layer의 데이터는 통신망 및 단말기의 QoS에 따라 서로 다른 전송 채널을 통해 서버에서 클라이언트 디코더로 전송된 후 디코더에 실시간적으로 병합한 후 재생된다. 본 논문에서 제안하는 기법을 이용하여 기존에 encoding MPEG-2 Video steam의 AC계수를 layering할 경우에 QoS에 따라 가변적으로 데이터 양을 서버 쪽에서 조절할 수 있었고, 통신 선로 상에서 이동하는 데이터 양의 원래의 MPEG-2 Video steam 을 이용했을 때보다 인코딩 중에 블록을 변환하면 51% 정도 감소하고 인코딩 되어진 데이터를 이용했을 경우에는25%정도 감소하는 것을 알 수 있었다.

• ETRI Journal
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• v.35 no.3
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• pp.469-479
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• 2013

This paper proposes an efficient computation-aware mode decision and search point (SP) allocation algorithm for spatial and quality scalabilities in Scalable Video Coding. In our proposal, a linear model is derived to allocate the computation for macroblocks in enhancement layers by using the rate distortion costs of the base layer. In addition, an adaptive SP decision algorithm is proposed to decide the number of SPs for motion estimation under the constraint of the allocated computation. Experiment results demonstrate that the proposed algorithm allocates the computation resource efficiently and outperforms other works in rate distortion performance under the same computational availability constraint.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.160-162
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• 2014

A programmable video decoding system with multi-core DSP and co-processors is presented. This system is adopted by Digital TV SoC (System on Chip) and is used for FHD HEVC (High Efficiency Video Coding) decoder. Using the DSP based programmable solution, we can reduce commercialization period by one year because we can parallelize algorithm development, software optimization and hardware design. In addition to the HEVC decoding, the proposed system can be used for other application such as other video decoding standard for multi-format decoder or video quality enhancement.

• ETRI Journal
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• v.35 no.6
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• pp.990-1000
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• 2013

This paper describes the scalable extension of High Efficiency Video Coding (HEVC) to provide flexible high-quality digital video content services. The proposed scalable codec is designed on multi-loop decoding architecture to support inter-layer sample prediction and inter-layer motion parameter prediction. Inter-layer sample prediction is enabled by inserting the reconstructed picture of the reference layer (RL) into the decoded picture buffer of the enhancement layer (EL). To reduce the motion parameter redundancies between layers, the motion parameter of the RL is used as one of the candidates in merge mode and motion vector prediction in the EL. The proposed scalable extension can support scalabilities with minimum changes to the HEVC and provide average Bj${\o}$ntegaard delta bitrate gains of about 24% for spatial scalability and of about 21% for SNR scalability compared to simulcast coding with HEVC.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.108-113
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• 2009

Significant attention has recently been drawn to digital home photo albums that use face detection technology. The tendency can be found in home photo albums that people prefer to allocate concerned objects in the center of the image rather than the boundary when they take a picture. To improve detection performance and speed that are important factors of face detection task, this paper proposes a face detection method that takes spatial context information into consideration. Experiments were performed to verify the usefulness of the proposed method and results indicate that the proposed face detection method can efficiently reduce the false positive rate as well as the runtime of face detection.