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인터넷 동영상 전송을 위한 시공간 적응형 오류 은닉 기법
유국열,정호열 嶺南大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.30 No.2
In this paper, we propose the adaptive spatio-temporal error concealment method for the transmission of the compressed video signals over the Internet. Conventionally, the ITU-T VCEG(Video Coding Experts Group) has been used the error concealment method, TCON for the evaluation of various video coding methods for the transmission of the coded video bitstream over the Internet. The TCON method uses the temporal information for the error concealment, in other words, motion vector from the above GOB(Group Of Block) if the GOB is correctly received at the decoder. The lost portion of the video signal cannot be, however, compensated when the part experiences 3-dimensional motion or it is inside the new object which does not exist in the previous picture. For the such area, the spatial information is more appropriate in the recovery in the decoder side. In this paper, we proposed the adaptive spatio-temporal concealment method which adaptively uses the temporal information like TCON and the spatial information for the portion which cannot be compensated by the temporal information. The simulation results show that the proposed method significantly improves the error concealment method compared with the conventional TCON method.
인터넷 동영상 전송을 위한 패킷손실에 강인한 패킷화 및 동영상부호화 기법
유국열,Yoo Kook-yeol 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.11c
본 논문에서는 인터넷을 통해서 압축된 동영상을 패킷 손실에 강인하게 전송하기 위한 부호화 방식을 제안하고, 이를 위한 패킷화 방식 및 복호화 방식을 제안하였다. 제안 방식은 입력 영상을 효과적으로 재구성하여 부호화 및 패킷화를 수행하여, 한 개의 영상에 해당하는 일부 패킷이 네트워크에서 유실되었을 경우에 올바르게 수신된 패킷내에 있는 영상 데이터를 통해서 복호화단에서 효율적으로 오류를 은닉하는 방식을 제시하였다. 제안 방식을 통해서 다양한 패킷 손실율에 대해서 제안 방식의 효율성을 검증하였다. 제안 방식은 인터넷에만 국한되지 않고, 다양한 형태의 패킷망에서 효과적인 동영상 전송 기법으로 사용될 수 있다. In this paper we propose a video coding method and associated packetization and decoding methods for error resilient transmission over the Internet. The proposed method re-organizes the input image into several mutually similar subimages. For this case, if the one of the subimage is lost in the network, the lost one is recovered by the proposed error concealment method which uses the correctly received other subimages. The performance of the proposed method is confirmed by the empirical results. The proposed method is not limited to the Internet communications but is applicable to the other packet-based networks.
Block Motion Vector Recovery by Neighborhood Matching
김재균,Kook Yeol Yoo 대한전자공학회 1994 ISPACS:Intelligent Signal Processing and Communica Vol.1 No.1
The digital video services in the B-ISDN network require the transmission of a large amount of information within a highly restricted bandwidth. Transmitting coded bitstream over networks, channel errors are inevitable due to transmission constraints. Currently most of video coders adopt the MCDCT techniques. In such coders, the loss of motion information result in fatal quality degradation, and furthermore, errors are propagated into the next reconstruction images. A novel recovery method of lost motion information, based on motion estimation at the decoder side, is proposed in this paper. Luminance intensities enclosing block with motion information loss are used in the estimation. The emperical results show that the proposed algorithm achieves better performance in PSNR and subjective quality than conventional recovery methods of motion information, such as average method and median filter.
Serial Changes of Heat Shock Protein 70 and Interleukin-8 in Burn Blister Fluid
( Kicheol Yoo ),( Kang Yeol Suh ),( Gi Hun Choi ),( In-suk Kwak ),( Dong Kook Seo ),( Dohern Kym ),( Hyeon Yoon ),( Yong Se Cho ),( Hye One Kim ) 대한피부과학회 2017 Annals of Dermatology Vol.29 No.2
Background: It has been reported that heat shock protein 70 (HSP70) and interleukin-8 (IL-8) play an important role in cells during the wound healing process. However, there has been no report on the effect of HSP70 and IL-8 on the blisters of burn patients. Objective: This study aimed to evaluate the serial quantitative changes of HSP70 and IL-8 in burn blisters. Methods: Twenty-five burn patients were included, for a total of 36 cases: twenty cases on the first day, six cases on the sec-ond, five cases on the third, three cases on the fourth, and two cases on the fifth. A correlation analysis was performed to de-termine the relationship between the concentration of HSP70 and IL-8 and the length of the treatment period. Results: The HSP70 concentration was the highest on the first day, after which it decreased down to near zero. Most HSP70 was generated during the first 12 hours after the burn accident. There was no correlation between the concen-tration of HSP70 on the first day and the length of the treat-ment period. No measurable concentration of IL-8 was de-tected before 5 hours, but the concentration started to in-crease after 11 hours. The peak value was measured on the fourth day. Conclusion: While HSP70 increased in the first few hours and decreased afterwards, IL-8 was produced after 11 hours and increased afterward in burn blister fluid. These findings provide new evidence on serial changes of in-flammatory mediators in burn blister fluid. (Ann Dermatol 29(2) 194∼199, 2017)
A Hierarchical Mode Decision Method for H.264 Intra Image Coding
( Jiantan Liu ),( Kook-yeol Yoo ) 한국정보처리학회 2007 한국정보처리학회 학술대회논문집 Vol.14 No.1
Due to its impressive compression performance, the H.264 video coder is highlighted in the video communications industry, such as DMB (Digital Multimedia Broadcasting), PMP (Portable Multimedia Player), etc. The main bottleneck to use the H.264 coder lays in the computational complexity, i.e. five times more complex than the market leading MPEG-4 Simple Profile codec. In this paper, we propose the hierarchical mode decision method for intraframe coding for the reduction of the computation complexity of the encoder. By determining the mode group early, the propose algorithm can skip the computationally demanding computation in the mode decision. The proposed algorithm is composed of three steps: 16x16 mode decision, 4x4 mode-group decisions, and final mode decision among the selected mode group. The simulation results show that the proposed algorithm achieves 20% to 50% reduction in the computational complexity compared with the conventional algorithm.
Low complexity intra prediction algorithm for MPEG-2 to H.264/AVC transcoder
Liu, Xingang,Yoo, Kook-Yeol,Kim, Sung, Won IEEE 2010 IEEE transactions on consumer electronics Vol.56 No.2
<P>Transcoding MPEG-2 video into H.264/AVC format is highly necessary for the broad distribution of digital video contents to mobile terminals. Since H.264/AVC achieves great coding efficiency by employing computationally demanding algorithms, the computational complexity of the transcoder is one of technically challenging issues. The empirical results show that DCT energy trend in the decoded MB of MPEG-2 bitstream has strong correlation with the Intra prediction modes of H.264/AVC. Based on the relationship, the mode skipping rule of intra prediction mode decision in the H.264/AVC encoder part of the transcoder is proposed in this paper. The simulation results show that the proposed algorithm can achieve on average 72.36% reduction in computational complexity, compared with that of the conventional transcoder.</P>