• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.10-17
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• 2009

Wyner-Ziv video coding is a new video compression paradigm based on distributed source coding theory of Slepian-Wolf and Wyner-Ziv. Wyner-Ziv coding enables light-encoder/heavy-decoder structure by shifting complex modules including motion estimation/compensation task to the decoder. Instead of performing the complicated motion estimation process in the encoder, the Wyner-Ziv decoder performs the motion estimation for the generation of side information in order to make the predicted signal of the Wyner-Ziv frame. The efficiency of side information generation deeply affects the overall coding performance, since the bit-rates of the Wyner-Ziv coding is directly dependent on side information. In this paper, an improved side information generation method using field coding is proposed. In the proposed method, top fields are coded with the existing SI generation method and bottom fields are coded with new SI generation method using the information of the top fields. Simulation results show that the proposed method improves the quality of the side information and rate-distortion performance compared to the conventional method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1912-1920
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• 1999

In this paper, we propose a layered video coding scheme which can generate multi-layered bitstream for heterogeneous environments. A new motion prediction structure with temporal hierarchy of frames is developed to afford temporal resolution scalability and the wavelet decomposition is adopted to offer spatial acalability. The proposed scheme can have a higher compression ratio than replenishment schemes by using motion estimation and compensation which can further reduce the temporal redundancy, and it effectively works with dynamic adaption or errors using dispersive intra-subband update (DISU). Moreover, data rate scalability can be attained by employing embeded zerotree wavelet (EZW) technique which can produce embeded bitstream. Therefore, the proposed scheme is expected to be effectively used in heterogeneous environments such as the Internet, ATM, and mobile networks where interoperability are required.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.778-786
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• 2008

The H.264/AVC video coding standard shows superior coding efficiency by adopting many new techniques. However, the encoding complexity increases greatly to achieve higher coding efficiency. Especially, the rate distortion optimization technique, which is used to decide the intra-prediction mode, increases the encoding complexity. In this paper, we propose an efficient intra-prediction mode decision method. By using the variance of pixel values and the edge direction, the computational complexity of the intra-prediction mode decision is greatly reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.583-590
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• 2008

In this paper, we present a spatially adaptive post-processing algorithm for H.264 video coding standard to remove blocking artifacts. The loop filter of H.264 increases computational complexity of the encoder. Furthermore it doesn't clearly remove the blocking artifacts, resulting in over-blurring. For overcoming them, we combine the projection method with the Constraint Least Squares(CLS) method to restore the high quality image. To reflect the Human Visual System, we adopt the weight norm CLS method. Particularly pixel location-based local variance and laplacian operator are newly defined for the CLS method. In addition, the fact that correlation among adjoining pixels is high is utilized to constrain the solution space when the projection method is applied. Quantization Index(QP) of H.264 is also used to control the degree of smoothness. The simulation results show that the proposed post-processing filter works better than the loop filter of H.264 and converges more quickly than the CLS method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.34-42
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• 2012

Low density parity check (LDPC) code is widely used, since it shows superior performance close to Shannon limit and its decoding complexity is lower than turbo code. Recently, it is used as a channel code to decode Wyner-Ziv frames in distributed video coding (DVC) system. In this paper, we propose an efficient method to design the parity check matrix H of LDPC codes. In order to apply LDPC code to DVC system, the LDPC code should have rate compatibility. Thus, we also propose a method to merge check nodes of LDPC code to attain the rate compatibility. LDPC code is designed using ACE algorithm and check nodes are merged for a given code rate to maximize the error correction capability. The performance of the designed LDPC code is analyzed extensively by computer simulations.

• Journal of Broadcast Engineering
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• v.18 no.4
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• pp.599-608
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• 2013

Motion compensated interpolation (MCI) techniques are used for increasing the frame rate and generating the side information in the distributed video coding (DVC) system. In this paper, an efficient MCI technique using the image resizing in the DCT or LiftLT domain is proposed, and the performance of the MCI technique using various sub-pixel generation techniques is analyzed. Extensive computer simulations show that the proposed method produces the superior results compared to the conventional methods.

• Journal of Broadcast Engineering
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• v.2 no.2
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• pp.146-155
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• 1997

The new video coding standard Iv1PEG-4 is enabling content-based functionalities. It requires a prior decomposition of sequences into video object planes (VOP's) so that each VOP represents moving objets. This paper addresses an image segmentation method for separating moving objects from still background (non-moving area) in video sequences using a statistical hypothesis test. In the proposed method. three consecutive image frames are exploited and a hypothesis testing is performed by comparing two means from two consecutive difference images. which results in a T-test. This hypothesis test yields a change detection mask that indicates moving areas (foreground) and non-moving areas (background), Moreover. an effective method for extracting

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.24-27
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• 2010

움직임 보상 외삽 기법은 전송중 손상된 프레임의 복원 및 프레임율 증가 뿐 아니라 분산 동영상 부호화 시스템(distributed video coding:DVC)의 부가 정보(side information) 생성에도 활용될 수 있다. 본 논문에서는 기존의 다양한 움직임 보상 외삽기법의 성능을 평가하고 정방향과 역방향 움직임 예측을 함께 이용한 효율적인 움직임 보상 외삽 기법을 제안한다. 모의 실험결과 제안하는 기법이 기존의 기법에 비해서 우수한 성능을 보임을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4C
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• pp.207-216
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• 2011

Motion compensated extrapolation (MCE) techniques show inferior performance compared to motion compensated interpolation techniques, since only past frames are used in MCE. MCE techniques are used for the reconstruction of corrupted frames, the up-conversion of frame rates and the generation of side information in the distributed video coding system. In this paper, the performance of various MCE techniques are evaluated and an efficient MCE technique using the forward and backward motion estimation is proposed. In the proposed technique, the present frame is extrapolated by averaging two frames which are generated by forward and backward motion estimation respectively. It is shown that the proposed method produces better PSNR results and less blocking phenomena than conventional methods.