• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.269-272
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• 2007

The shortcut shot detection based on MPEG compressed video bitstream is presented in this paper. The detection algorithm is used the video picture frame from MPEG compressed video directly not to be decompressed the original image. For shortcut detection, I and P frame of MPEG video bitstream are classified. The changing scene cuts at I pictures are detected by the decompressed DC image and scene cuts at P picture frame by monitoring the percentage of intra-macroblocks per P picture are detected. Experimental results using test video bitstream QVGA results in average 92% detection rate, searching time is taken around 4.5 times faster in comparison with changing scene shot detection algorithm which is decompressed the compressed bitstream.

• 한국통신학회논문지
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• 제31권4C호
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• pp.458-471
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• 2006

Digital watermarking of multimedia data is a very active research area that has enjoyed a considerable amount of attention in recent years. In this paper, we propose an algorithm for embedding/detecting a fragile watermark in MPEG-4 compressed video domain (Simple and Advance Simple Profiles). The watermark bits are put directly into Huffman VLC-codespace of quantized DCT domain. The advantage of watermark embedding into the compressed domain is the significant savings for a real-time implementation as it does not require a full decoding operation. The watermark embedding does not change the video file size. The algorithm demonstrates high watermarking capacity, thereby providing reliable foolproof authentication. The results of experimental testing demonstrate that watermark embedding preserves the video quality. Watermark detection is performed without using the original video.

• 한국멀티미디어학회논문지
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• 제20권5호
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• pp.731-739
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• 2017

Distributed compressed video sensing (DCVS) is a framework that integrates both compressed sensing and distributed video coding characteristics to achieve a low complexity video sampling. In DCVS schemes, motion estimation & motion compensation is employed at the decoder side, similarly to distributed video coding (DVC), for a low-complex encoder. However, since a simple BCS-SPL algorithm is applied to a residual arising from motion estimation and compensation in conventional MC-BCS-SPL (motion compensated block compressed sensing with smoothed projected Landweber) scheme, the reconstructed visual qualities are severly degraded in Wyner-Ziv (WZ) frames. Furthermore, the scheme takes lots of iteration to reconstruct WZ frames. In this paper, the conventional MC-BCS-SPL algorithm is improved to be operated in more effective way in WZ frames. That is, first, the proposed algorithm calculates a correlation coefficient between two reference key frames and, then, by selecting adaptively the reference frame, the residual reconstruction in pixel domain is performed to the conventional BCS-SPL scheme. Experimental results show that the proposed algorithm achieves significantly better visual qualities than conventional MC-BCS-SPL algorithm, while resulting in the significant reduction of the decoding time.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2018년도 추계학술대회
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• pp.133-134
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• 2018

MPEG-NNR (Compressed Representation of Neural Networks) aims to define a compressed and interoperable representation of trained neural networks. In this paper, a compressed representation of NN and its evaluation performance along with use cases of image/video compression in MPEG-NNR are presented. In the compression of NN, a CNN to replace the in-loop filter in VVC (Versatile Video Coding) intra coding is compressed by applying uniform quantization to reduce the trained weights, and the compressed CNN is evaluated in terms of compression ratio and coding efficiency compared to the original CNN. Evaluation results show that CNN could be compressed to about quarter with negligible coding loss by applying simple quantization to the trained weights.

• 한국정보처리학회논문지
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• 제5권6호
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• pp.1431-1440
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• 1998

동영상 정보는 자료의 양이 방대하고 다양하여 압축된 형태로 저장하고 검색하는 것이 매우 중요하다. 본 논문에서는 동영상 문서의 구조를 추출하고 동영상 스트림의 인데싱에 대한 의미를 부여할 수 있는 일반적인 데이터 모델을 제시하고, 이 모델을 이용하여 MPEG-2로 압축된 동영상 자료를 데이터베이스에 저장하고 검색하는 MPEG-2 압축 동영상 정보 관리 시스템(CVIMS, Compressed Video Information Management System)을 제안한다. CVIMS는 MPEG-2 파일에서 I-프레임들을 추출하고, 그 중에서 키 프레임(대표 이미지)을 선택한 후, 선택된 키 프레임에 대한 축소그림(thumbnail)과 캡션 및 그림 설명 정보를 데이터베이스에 저장한다. 그리고 데이터베이스에 저장된 MPEG-2 동영상을 질의어나 키 프레임을 통해 검색한다.

• 대한전자공학회논문지SP
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• 제46권3호
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• pp.10-17
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• 2009

본 논문은 H.264/AVC 비디오 압축영역에서 비디오 복제 방지기법의 일종인 CBCD(Content Based Copy Detection)에 사용 될 수 있는 비디오 시그너쳐 (Video Signature) 추출 방법을 제안한다. 기존의 비디오 시그너쳐 추출방법은 모두 비디오 공간영 역에서 수행되기 때문에 압축된 비디오 스트립으로부터 시그너쳐를 추출하기 위해서는 비디오를 모두 복호해야 하는 단점을 가지고 있었다. 하지만 제안하는 방법에서는 비디오 압축영역에서 섬네일(Thumbnail)을 빠르게 구성하고 구성된 섬네일을 이용하여 비디오 시그너쳐를 추출하여 이와 같은 단점을 극복하였다. 밝기 순서 정보를 추출하는 실험결과로부터 제안하는 방법은 기존의 방법보다 80.98%의 정확도를 유지하면서 약 2.8배 빠르게 시그너쳐를 추출할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.867-870
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• 1998

Video data is usually stored in a compressed format in order to reduce the storage space. For efficient browsing, searching, and retrieval of compressed video sequences, size-reduced images (or DC images which are formed with block DC coefficients) are generally preferred to avoid unnecessary computational complexity. In this paper, we propose a DC image extraction scheme appropriate for scene analysis and efficient browsing of compressed video sequences. The proposed algorithm utilizes predicted low frequency AC coefficients to achieve better approximation and to reduce the error drift. Due to the AC prediction based on a quadratic surface model, the proposed scheme requires no additional memory compared with the previous zero-order or first-order approximation scheme. Simulation results show that the proposed scheme achieves better subjective and objective quality with minor additional operations.

• 한국멀티미디어학회논문지
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• 제15권6호
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• pp.693-700
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• 2012

The effective extraction of key frames from a video stream is an essential task for summarizing and representing the content of a video. Accordingly, this paper proposes a new and fast method for extracting key frames from a compressed video. In the proposed approach, after the entire video sequence has been segmented into elementary content units, called shots, key frame extraction is performed by first assigning the number of key frames to each shot, and then distributing the key frames over the shot using a probabilistic approach to locate the optimal position of the key frames. The main advantage of the proposed method is that no time-consuming computations are needed for distributing the key frames within the shots and the procedure for key frame extraction is completely automatic. Furthermore, the set of key frames is independent of any subjective thresholds or manually set parameters.

• 한국통신학회논문지
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• 제21권6호
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• pp.1370-1378
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• 1996

A subjective video quality assessment methods are proposed based on CCIR Rec. 500-5 for an evaluation and testing of compressed video quality and performance of video codec to be designed in accordance with the MPEG-2 MP ML specification which is adapted as a DTV standard for Korea digital DBS. Video sequence compressed in compliance with MPEG-2 MP ML encoding parameterswastested by the proposed video quality evaluation procedure. Test sequence were compressed at the bit rate 6Mbps, 7.5Mbps and 9Mbps, repectively. Test results of the 7.5Mbps bitrate showed a satisfactory picture quality at about 4.0 on the 5.0 absolute scale of ITU-R 500-5.

• 한국통신학회논문지
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• 제39C권6호
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• pp.503-511
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• 2014

본 논문에서는 사용자가 하나의 화면을 가진 장치에서 원하는 여러 비디오 콘텐츠를 동시에 볼 수 있도록 하는 새로운 실시간 H.264/AVC 압축 영역에서의 영상 합성 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 사용자의 요청에 따른 다수 비트스트림들을 압축 영역에서의 하나의 비트열으로 합성한다. 즉, 압축 영역에 있는 다수 영상들의 경계면에 있는 매크로블록들에 대해서 화면 내 예측 모드와 화면 간 예측 MVD를 다시 계산하고 변환 오차 계수 테이블을 수정 하여 경계 매크로블록 확정하는 방법, 영상의 나머지 부분에서 매크로블록 데이터를 단순히 복사하는 방법으로 이뤄진다. 실험 결과, 제안 알고리즘은 480p 크기의 4개 영상을 1초에 103장 이상 합성할 수 있어, 실시간 적용의 가능함을 보여주고 있다.