• Title/Summary/Keyword: concealment and concealment

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A Temporal Error Concealment Technique Using Motion Adaptive Boundary Matching Algorithm

  • Kim Won Ki;Jeong Je Chang
    • Proceedings of the IEEK Conference
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    • 2004.08c
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    • pp.819-822
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    • 2004
  • To transmit MPEG-2 video on an erroneous channel, a number of error control techniques He needed. Especially, error concealment techniques which can be implemented on receivers independent of transmitters are essential to obtain good video quality. In this paper, a motion adaptive boundary matching algorithm (MA-BMA) is presented for temporal error concealment. Before carrying out BMA, we perform error concealmmt by a motion vector prediction using neighboring motion vectors. If the candidate of error concealment is rot satisfied, search range and reliable boundary pixels are selected by the motion activity or motion vectors ane a damaged macroblock is concealed by applying the MA-BMA. This error concealment technique reduces the complexity and maintains PSNR gain of 0.3 0.7dB compared to the conventional BMA.

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Video Error Concealment using Neighboring Motion Vectors (주변의 움직임 벡터를 사용한 비디오 에러 은닉 기법)

  • 임유두;이병욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.3C
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    • pp.257-263
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    • 2003
  • Error control and concealment in video communication is becoming increasingly important because transmission errors can cause single or multiple loss of macroblocks in video delivery over unreliable channels such as wireless networks and the internet. This paper describes a temporal error concealment by postprocessing. Lost image blocks are overlapped block motion compensated (OBMC) using median of motion vectors from adjacent blocks at the decoder. The results show a significant improvement over zero motion error concealment and other temporal concealment methods such as Motion Vector Rational Interpolation or Side Match Criterion OBMC by 1.4 to 3.5㏈ gain in PSNR. We present experimental results showing improvements in PSNR and computational complexity.

Error concealment for Low Bit Rate Video over Burst-packet-Loss Networks (다발적 패킷 손실 네트워크에서 저비트율 영상의 에러은닉)

  • 정진우;변재영;고성제
    • Proceedings of the IEEK Conference
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    • 2003.11a
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    • pp.271-274
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    • 2003
  • This paper presents a robust error concealment method for burst-packet-loss networks. The proposed error concealment algorithm can reduce the computational complexities of the existing error concealment methods. Moreover, experimental results show that the proposed method produces the better video quality than the conventional boundary matching algorithm.

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Working Alliance in Parent Consultation : Relationships with Mothers' Level of Self-concealment and Perception of Social Support (부모상담에서 어머니의 자기은폐 수준 및 지각된 사회적 지지와 작업동맹의 관계)

  • Oh, Ji Hyun;Sung, Young Hye;Cho, You Jin
    • Korean Journal of Child Studies
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    • v.29 no.6
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    • pp.193-206
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    • 2008
  • This research studied mothers of clients to examine relationships between level of self-concealment and level of perception of social support in the working alliance (goal concurrence, task agreement, and emotional relationships during parent consultation) as perceived by the therapist, Subjects were 87 mothers of clients and 42 therapists. The parent consultation sessions examined in this study ranged from the 3rd to the 12th session. Data were analyzed by simple regression and two-way ANOVA. Results showed that (1) the level of self-concealment affected all components of working alliance. (2) Perception of social support level affected all components of working alliance. (3) Interaction effects of levels of self-concealment with perception of social support were significant.

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High-Performance Spatial and Temporal Error-Concealment Algorithms for Block-Based Video Coding Techniques

  • Hsu, Ching-Ting;Chen, Mei-Juan;Liao, Wen-Wei;Lo, Shen-Yi
    • ETRI Journal
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    • v.27 no.1
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    • pp.53-63
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    • 2005
  • A compressed video bitstream is sensitive to errors that may severely degrade the reconstructed images even when the bit error rate is small. One approach to combat the impact of such errors is the use of error concealment at the decoder without increasing the bit rate or changing the encoder. For spatial-error concealment, we propose a method featuring edge continuity and texture preservation as well as low computation to reconstruct more visually acceptable images. Aiming at temporal error concealment, we propose a two-step algorithm based on block matching principles in which the assumption of smooth and uniform motion for some adjacent blocks is adopted. As simulation results show, the proposed spatial and temporal methods provide better reconstruction quality for damaged images than other methods.

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Multi-Hypothesis Error Concealment Algorithm for H.26L Video (H.26L을 위한 다차원 에러 은닉 기법)

  • 박영오;김창수;이상욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.11C
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    • pp.1130-1139
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    • 2003
  • In this work, we propose a multi-hypothesis error concealment algorithm, which replaces a lost block with a weighted superposition of more than two reference blocks in previous frames. Three methods are developed to find the set of reference blocks and determine the weighting coefficients. These methods are implemented based on H.26L standard, and their performances are evaluated. It is shown that the proposed multi-hypothesis algorithm provides up to 1.5㏈ better PSNR performance than the conventional single-hypothesis concealment algorithm.

Error Concealment Techniques for Visual Quality Improving (화질 향상을 위한 오류 은폐 기법)

  • Suh, Jae-Won
    • The Journal of the Korea Contents Association
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    • v.6 no.2
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    • pp.65-74
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    • 2006
  • The MPEG-2 video compressed bitstream is very sensitive to transmission errors due to the complex coding structure of the MPEG-2 video coding standard. If one packet is lost or received with errors, not only the current frame will be corrupted, but also errors will propagate to succeeding frames within a group of pictures. Therefore, we employ various error resilient coding/decoding techniques to protect and reduce the transmission error effects. Error concealment technique is one of them. Error concealment technique exploits spatial and temporal redundancies of the correctly received video data to conceal the corrupted video data. Motion vector recovery and compensation with the estimated motion vector is good approach to conceal the corrupted data. In this paper, we propose various error concealment algorithms based on motion vector recovery, and compare their performance to those of conventional error concealment methods.

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Design and Implementation of Error Concealment Algorithm using Data Hiding and Adaptive Selection of Adjacent Motion Vectors (정보숨김과 주변 움직임 벡터의 적응적 선택에 의한 에러은닉 알고리즘의 설계 및 구현)

  • Lee, Hyun-Woo;Seong, Dong-Su;Lee, Keon-Bae
    • The KIPS Transactions:PartB
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    • v.13B no.6 s.109
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    • pp.607-614
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    • 2006
  • In this paper, we propose an error resilience video coder which uses a hybrid error concealment algorithm. Firstly, the algorithm uses the error concealment with data hiding. If the hiding information is lost, the motion vector of lost macroblock is computed with adaptive selection of adjacent motion vectors and OBMC (Overlapped Block Motion Compensation) is applied with this motion vector. We know our algorithm is more effective in case of continuous GOB. The results show more significant improvement than many temporal concealment methods such as MVRI (Motion Vector Rational Interpolation) or existing error concealment using data hiding.

Mediating Effects of Self-Concealment in the Associations between Social Support, Self-Esteem, and Depression among College Students in Daegu and Gyeongbuk Areas (사회적 지지 및 자아존중감과 우울 간의 관계에서의 자기은폐의 매개효과 검증: 대구·경북지역 대학생을 중심으로)

  • Choi, Jung-Ah
    • The Journal of the Korea Contents Association
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    • v.15 no.10
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    • pp.236-252
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    • 2015
  • The purpose of this study is to examine the associations between social support, self-esteem, self-concealment, and depression among college students. The mediating effects of self-concealment and gender differences in the associations were also examined. This study investigated these relationships and the gender differences using structural equation modeling multi-group analysis. The data collected from 307 college students in Daegu and Gyeongbuk areas were analyzed. The results indicated that both social support and self-esteem had effects on depression indirectly through self-concealment, and self-esteem also had direct effects on depression. The indirect effects of self-concealment were statistically significant. There were no gender differences in these relationships. These results suggest that self-concealment should be focused to prevent or alleviate depression among college students.

A Temporal Error Concealment Technique Using The Adaptive Boundary Matching Algorithm (적응적 경계 정합을 이용한 시간적 에러 은닉 기법)

  • 김원기;이두수;정제창
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.5C
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    • pp.683-691
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    • 2004
  • To transmit MPEG-2 video on an errorneous channel, a number of error control techniques are needed. Especially, error concealment techniques which can be implemented on receivers independent of transmitters are essential to obtain good video quality. In this paper, prediction of motion vector and an adaptive boundary matching algorithm are presented for temporal error concealment. Before the complex BMA, we perform error concealment by a motion vector prediction using neighboring motion vectors. If the candidate of error concealment is not satisfied, search range and reliable boundary pixels are selected by the temporal activity or motion vectors and a damaged macroblock is concealed by applying an adaptive BMA. This error concealment technique reduces the complexity and maintains a PSNR gain of 0.3∼0.7㏈ compared to conventional BMA.