• Title/Summary/Keyword: Spatial Error Concealment

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An Image Concealment Algorithm Using Fuzzy Inference (퍼지 추론을 이용한 영상은닉 알고리즘)

  • Kim, Ha-Sik;Kim, Yoon-Ho
    • Journal of Advanced Navigation Technology
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    • v.11 no.4
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    • pp.485-492
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    • 2007
  • In this paper, we propose the receiver block error detection of the video codec and the image concealment algorithm using fuzzy inference. The proposed error detection and concealment algorithm gets SSD(Summation of Squared Difference) and BMC(Boundary Matching Coefficient) using the temporal and spatial similarity between corresponded blocks in the two successive frames. Proportional constant, ${\alpha}$, for threshold value, TH1 and TH2, is decided after fuzzy data is generated by each parameter. To examine the propriety of the proposed algorithm, random errors are inserted into the QCIF Susie standard image, then the error detection and concealment performance is simulated. To evaluate the efficiency of the algorithm, image quality is evaluated by PSNR for the error detection and concealed image by the existing VLC table and by the proposed method. In the experimental results, the error detection algorithm could detect all of the inserted error, the image quality is improved over 15dB after the error concealment compare to existing error detection algorithm.

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Spatial Smoothing for Temporal Error Concealment (시간적 에러 은폐를 위한 공간적 스무딩)

  • 김동욱;김진태
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.594-597
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    • 2003
  • In this paper, we propose a new temporal error concealment method for recovery of video packet loss. Error concealment for each loss block is performed by temporal motion compensation and a smoothing operation of boundary pixels between the compensated block and its surrounding blocks. In the simulation results, performance improvement for the proposed technique is on the average 2 dB in comparison with the conventional technique.

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Hybrid Error Concealment Algorithm for Intra-Frame in H.264 (H.264의 인트라 프레임을 위한 하이브리드 에러 은닉 알고리즘)

  • Yim Chang-Hoon;Kim Won-Jung;Lim Hye-Sook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.8C
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    • pp.777-785
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    • 2006
  • H.264 is the prominent video coding standard in various applications such as real-time video streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Since compressed video stream is vulnerable to packet loss, error resilience and error concealment(EC) tools are essential for the transmission of video over the Internet. In this paper, we first propose a simple temporal EC method that improves the EC performance for intra-frame in H.264 when the amount of motion is relatively small. Then we propose a new hybrid EC method for intra-frame in H.264, which combines the spatial EC and temporal EC adaptively. The simulations are performed in packet-lossy environments, and the proposed hybrid EC method shows about 0.5-4dB PSNR improvement compared to the conventional spatial EC method that is used for intra-frame in H.264.

A Spatial Error Concealment Using Pixelwise Fine Directional Interpolation (픽셀 단위의 정밀한 방향성 보간을 이용한 공간적 에러 은닉 기법)

  • Kim, Won-Ki;Koo, Ja-Sung;Jin, Soon-Jong;Jeong, Je-Chang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2C
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    • pp.124-131
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    • 2007
  • This paper presents a block loss recovery technique for the image block data corrupted by transmission losses through the employment of fine directional interpolation (FDI). The proposed algorithm introduces a spatial direction vector (SDV). The SDVs are extracted from the edge information of the neighboring image data. Subsequently, the SDVs are adaptively applied to interpolate lost pixels on a pixel-by-pixel basis. This approach improves the capability to more reliably recover high-detailed contents in the corrupted block. Experimental results demonstrate that the FDI method performs better as compared to previous techniques.

A Spatial Error Concealment Technique with Low Complexity for Intra-frame in the H.264 Standard (H.264 인트라 프레임을 위한 저복잡도(低複雜度) 공간적 에러은닉 기법)

  • Kim Dong-Hyung;Cho Sang-Hyup;Jeong Je-Chang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.5C
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    • pp.503-511
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    • 2006
  • H.264 adopts new coding tools such as intra-prediction, loop filter, etc. The adoption of these tools enables an H.264-coded bitstream to have more information compared with previous standards. In this paper we proposed an effective spatial error concealment method for H.264. Among the information included in an H.264-coded bitstream, we use intra-mode for recovering a damaged block. This is because prediction direction in intra-mode is highly correlated to the edge direction of a lost macroblock. We first estimate the edge direction using intra-modes of blocks adjacent to a lost macroblock, and classify the area in a damaged macroblock into the edge and the flat area. And then our method recovers pixel values in the edge area using edge-directed interpolation, and recovers pixel values in the flat area using weighted interpolation. Simulation results show the proposed method yields better video quality than conventional approaches by 0.35 to 5.48 dB.

Recovery of Missing Motion Vectors Using Modified ALA Clustering Algorithm (수정된 ALA 클러스터링 알고리즘을 이용한 손실된 움직임 벡터 복원 방법)

  • Son, Nam-Rye;Lee, Guee-Sang
    • The KIPS Transactions:PartB
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    • v.12B no.7 s.103
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    • pp.755-760
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    • 2005
  • To transmit a video bit stream over low bandwith, such as mobile, channels, encoding algorithms for high bit rate like H.263+ are used. In transmitting video bit-streams, packet losses cause severe degradation in image quality. This paper proposes a new algorithm for the recovery of missing or erroneous motion vectors when H.263+ bit-stream is transmitted. Considering that the missing or erroneous motion vectors are closely related with those of neighboring blocks, this paper proposes a temporal-spatial error concealment algorithm. The proposed approach is that missing or erroneous Motion Vectors(MVs) are recovered by clustering the movements of neighboring blocks by their homogeneity. MVs of neighboring blocks we clustered according to ALA(Average Linkage Algorithm) clustering and a representative value for each cluster 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 subjective and objective evaluation than existing methods.

An Efficient Error Concealment Method Using Difference Values of Border Pixels (경계 화소의 차분값을 이용한 효과적인 에러 은닉 방법)

  • Hyun, Seung-Hwa;Kim, Sang-Soo;Kim, Yoo-Shin;Eom, Il-Kyu
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.5
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    • pp.143-150
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    • 2009
  • In this paper, we present a spatial domain error concealment method to recover a lost block in intra-coded frames. The edge directions of the lost block are estimated by the difference values of the border pixels of the accurately received blocks. The lost block is interpolated according to the estimated edge directions. Our algorithm can adaptively recover a lost block according to the estimated edge direction. The distances between pixels are used as weights for interpolation. In spite of the low computational cost, the proposed method outperforms the previous methods in objective and subjective qualities.

A Boundary Matching and Post-processing Method for the Temporal Error Concealment in H.264/AVC (H.264/AVC의 시간적 오류 은닉을 위한 경계 정합과 후처리 방법)

  • Lee, Jun-Woo;Na, Sang-Il;Won, In-Su;Lim, Dae-Kyu;Jeong, Dong-Seok
    • Journal of Korea Multimedia Society
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    • v.12 no.11
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    • pp.1563-1571
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    • 2009
  • In this paper, we propose a new boundary matching method for the temporal error concealment and a post processing algorithm for perceptual quality improvement of the concealed frame. Temporal error concealment is a method that substitutes error blocks with similar blocks from the reference frame. In conventional H.264/AVC standard, it compares outside pixels of erroneous block with inside pixels of reference block to find the most similar block. However, it is very possible that the conventional method substitutes erroneous block with the wrong one because it compares only narrow spatial range of pixels. In this paper, for substituting erroneous blocks with more correct blocks, we propose enhanced boundary matching method by comparing inside and outside pixels of reference block with outside pixels of erroneous block and setting up additional candidate motion vector in the fixed search range based on maximum and minimum value of candidate motion vectors. Furthermore, we propose a post processing method to smooth edges between concealed and decoded blocks without error by using the modified deblocking filter. We identified that the proposed method shows quality improvement of about 0.9dB over the conventional boundary matching methods.

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Error Concealment Method for MPEG-4 Video in Wireless Environment (무선환경에서 MPEG-4 영상의 오류은닉 방법)

  • Park, Sun-Young;Song, Joon-Ho;Moon, Joo-Hee
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.6
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    • pp.641-651
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    • 2002
  • Recently, many advanced video application services over the mobile wireless networks have required a transcoder which can efficiently reduce the size of compressed video bitstreams. The transcoder can be worked in either the spatial domain or the DCT domain. In this paper, we propose a new fast hybrid-type transcoder which can efficiently reduce the frame size with keeping the visual quality. The proposed scheme consists of two major processes: a transform domain process and a spatial domain process. We also propose a scheme for coding mode selection and motion vector refinement. Experimental results show that our approach can reduce the computational complexity more than any other conventional spatial-domain transcoder with keeping the visual quality.