• Title/Summary/Keyword: 워터블록

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Feature Points Selection Using Block-Based Watershed Segmentation and Polygon Approximation (블록기반 워터쉐드 영역분할과 다각형 근사화를 이용한 특징점 추출)

  • 김영덕;백중환
    • Proceedings of the Korea Institute of Convergence Signal Processing
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    • 2000.12a
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    • pp.93-96
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    • 2000
  • In this paper, we suggest a feature points selection method using block-based watershed segmentation and polygon approximation for preprocessing of MPEG-4 mesh generation. 2D natural image is segmented by 8$\times$8 or 4$\times$4 block classification method and watershed algorithm. As this result, pixels on the watershed lines represent scene's interior feature and this lines are shapes of closed contour. Continuous pixels on the watershed lines are selected out feature points using Polygon approximation and post processing.

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Integrity Authentication Algorithm of JPEG Compressed Images through Reversible Watermarking (가역 워터마킹 기술을 통한 JPEG 압축 영상의 무결성 인증 알고리즘)

  • Jo, Hyun-Wu;Yeo, Dong-Gyu;Lee, Hae-Yeoun
    • The KIPS Transactions:PartB
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    • v.19B no.2
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    • pp.83-92
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    • 2012
  • Multimedia contents can be copied and manipulated without quality degradation. Therefore, they are vulnerable to digital forgery and illegal distribution. In these days, with increasing the importance of multimedia security, various multimedia security techniques are studied. In this paper, we propose a content authentication algorithm based on reversible watermarking which supports JPEG compression commonly used for multimedia contents. After splitting image blocks, a specific authentication code for each block is extracted and embedded into the quantized coefficients on JPEG compression which are preserved against lossy processing. At a decoding process, the watermarked JPEG image is authenticated by extracting the embedded code and restored to have the original image quality. To evaluate the performance of the proposed algorithm, we analyzed image quality and compression ratio on various test images. The average PSNR value and compression ratio of the watermarked JPEG image were 33.13dB and 90.65%, respectively, whose difference with the standard JPEG compression were 2.44dB and 1.63%.

Fast information extraction algorithm for object-based MPEG-4 application from MPEG-2 bit-streamaper (MPEG-2 비트열로부터 객체 기반 MPEG-4 응용을 위한 고속 정보 추출 알고리즘)

  • 양종호;원치선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.12A
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    • pp.2109-2119
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    • 2001
  • In this paper, a fast information extraction algorithm for object-based MPEG-4 application from MPEG-2 bit-steam is proposed. For object-based MPEG-4 conversion, we need to extract such information as object-image, shape-image, macro-block motion vector, and header information from MPEG-2 bit-stream. If we use the extracted information, fast conversion for object-based MPEG-4 is possible. The proposed object extraction algorithm has two important steps, namely the motion vectors extraction from MPEG-2 bit-stream and the watershed algorithm. The algorithm extracts objects using user\`s assistance in the intra frame and tracks then in the following inter frames. If we have an unsatisfactory result for a fast moving object, the user can intervene to correct the segmentation. The proposed algorithm consist of two steps, which are intra frame object extracts processing and inter frame tracking processing. Object extracting process is the step in which user extracts a semantic object directly by using the block classification and watersheds. Object tacking process is the step of the following the object in the subsequent frames. It is based on the boundary fitting method using motion vector, object-mask, and modified watersheds. Experimental results show that the proposed method can achieve a fast conversion from the MPEG-2 bit-stream to the object-based MPEG-4 input.

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Fast information extraction algorithm for object-based MPEG-4 conversion from MPEG-1,2 (MPEG-1,2로부터 객체 기반 MPEG-4 변환을 위한 고속 정보 추출 알고리즘)

  • 양종호;박성욱
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.41 no.3
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    • pp.91-102
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    • 2004
  • In this paper, a fast information extraction algorithm for object-based MPEG-4 application from MPEG-1,2 is proposed. For object-based MPEG-4 conversion, we need to extract such information as object-image, shape-image, macro-block motion vector, and header information from MPEG-1,2 bit-stream. If we use the extracted information, fast conversion for object-based MPEG-4 is possible. The proposed object extraction algerian has two important steps, namely the motion vector extraction from MPEG-1,2 bit-stream and the watershed algerian The algorithm extracts objects using user's assistance in the intra frame and tracks then in the following inter frames. If we have an unsatisfactory result for a fast moving object the user can intervene to connect the segmentation. The proposed algorithm consist of two steps, which are intra frame object extracting processing and inter frame tracking processing. Object extracting process is the step in which user extracts a semantic object directly by using the block classification and watersheds. Object tracking process is the step of the following the object in the subsequent frames. It is based on the boundary fitting method using motion vector, object-mask and modified watersheds. Experimental results show that the proposed method can achieve a fast conversion from the MPEG-1,2 bit-stream to the object-based MPEG-4 input.

Block-based Color Image Segmentation Using Y/C Bit-Plane Sum]nation Image (Y/C 비트 평면합 영상을 이용한 블록 기반 칼라 영상 분할)

  • Kwak, No-Yoon
    • Journal of Digital Contents Society
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    • v.1 no.1
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    • pp.53-64
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    • 2000
  • This paper is related to color image segmentation scheme which makes it possible to achieve the excellent segmented results by block-based segmentation using Y/C bit-plane summation image. First, normalized chrominance summation image is obtained by normalizing the image which is summed up the absolutes of color-differential values between R, G, B images. Secondly, upper 2 bits of the luminance image and upper 6bits of and the normalized chrominance summation image are bitwise operated by the pixel to generate the Y/C bit-plane summation image. Next, the Y/C bit-plane summation image divided into predetermined block size, is classified into monotone blocks, texture blocks and edge blocks, and then each classified block is merged to the regions including one more blocks in the individual block type, and each region is selectively allocated to unique marker according to predetermined marker allocation rules. Finally, fine segmented results are obtained by applying the watershed algorithm to each pixel in the unmarked blocks. As shown in computer simulation, the main advantage of the proposed method is that it suppresses the over-segmentation in the texture regions and reduces computational load. Furthermore, it is able to apply global parameters to various images with different pixel distribution properties because they are nonsensitive for pixel distribution. Especially, the proposed method offers reasonable segmentation results in edge areas with lower contrast owing to the regional characteristics of the color components reflected in the Y/C bit-plane summation image.

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Robust Watermarking Using a Block-based Statistical Analysis in DCT Domain (DCT 영역에서 블록 기반의 통계적 분석을 이용한 강인한 워터마킹)

  • Lim, Hyun;Kim, Gui-Hyun;Park, Soon-Young;Bang, Man-Won
    • Proceedings of the IEEK Conference
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    • 2001.09a
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    • pp.657-660
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    • 2001
  • In this paper, a robust watermarking technique is presented by using a block-based statistics in DCT domain. First, the proposed technique calculates JND threshold value using the global statistics in DCT domain. Then watermark insertion is carried out by inserting one watermark into coefficients which are above the threshold value J within a 2${\times}$2 block. Finally, watermark is estimated by averaging the extracted watermarks from the coefficients which are above the threshold in a window. In experiments it is shown that the proposed techniques can enhance perceptual invisibility and robustness against additive noise and JPEG compression attacks by using the characteristics of JND.

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The Object Based Image Masking Algorithm (객체기반 초상권 보호 영상처리 알고리듬)

  • 윤호석;임재혁;전우성;원치선
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1999.11b
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    • pp.93-98
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    • 1999
  • 본 논문에서는 영상 내 존재하는 의미 있는 객체단위로 초상권을 보호하는 기법을 제안한다. 제안된 방법은 초상권 보호 객체선택 단계와 객체에 마스크를 적용하는 단계 그리고 마스크가 적용된 객체를 추적하는 단계로 나누어진다. 초상권 보호 객체선택 단계에서는 블록분류(block classification) 및 워터쉐드(watershed) 알고리듬을 이용하여 분할된 결과영상을 얻고 이를 이용하여 사용자가 원하는 객체를 마우스로 클릭함으로써 손쉽게 초상권 보호법을 적용시킬 객체를 추출할 수 있다. 이렇게 정의된 객체는 다음 단계에서 마스크를 적용 받게 된다. 첫 번째 프레임에서 마스크가 적용되면 다음 프레임부터는 객체추적과정에서 연된 화면사이의 움직임 및 밝기정보에 의해 객체를 추적, 계속 마스크를 적용함으로써 초상권을 보호할 수 있다. 제안된 알고리듬은 초상권 보호를 위한 모자이크 처리 시 화질 저하에 따른 시청자의 화면 거부감을 최소화시키고, 반자동영상분할 알고리듬을 사용하여 객체 단위로 초상권 마스크를 적용하여 초상권 보호대상물을 놓치지 않고 추적할 수 있어 신뢰도를 높일 수 있는 장점을 가지고 있다.

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Video Watermarking Scheme on H.264/AVC using Selective Block Embedding (선택적 블록 삽입을 통한 H.264/AVC에서의 비디오 워터마킹 방법)

  • Kim, Jung-Min;Choi, Young-Soo;Kim, Hyoung-Joong
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.10 no.2
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    • pp.46-52
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    • 2011
  • This paper presents adaptive spread-spectrum watermarking scheme on the H.264/AVC video. The H.264/AVC has become popular video coding since it's compression performance has been improved greatly. That is why there is not enough space for embedding watermark using the spread-spectrum method. To overcome this problem, we propose selective block embedding scheme. The blocks which don't contain non-zero DCT (Discrete Cosine Transform) coefficients are selected by value. So we have enough space to embed watermarks. Experimental result shows that proposed scheme improves recovery rates of watermark about 12% and reduces distortion of watermarked video.

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Error Detection and Concealment of Transmission Error Using Watermark (워터마크를 이용한 전송 채널 에러의 검출 및 은닉)

  • 박운기;전병우
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.2C
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    • pp.262-271
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    • 2004
  • There are channel errors when video data are transmitted between encoder and decoder. These channel errors would make decoded image incorrect, so it is very important to detect and recover channel errors. This paper proposes a method of error detection and recovery by hiding specific information into video bitstream using fragile watermark and checking it later. The proposed method requires no additional bits into compressed bitstream since it embeds a user-specific data pattern in the least significant bits of LEVELs in VLC codewords. The decoder can extract the information to check whether the received bitstream has an error or not. We also propose to use this method to embed essential data such as motion vectors that can be used for error recovery. The proposed method can detect corrupted MBs that usually escape the conventional syntax-based error detection scheme. This proposed method is quite simple and of low complexity. So the method can be applied to multimedia communication system in low bitrate wireless channel.

Reversible Data Hiding Method Based on Min/Max in 2×2 Sub-blocks (2×2 서브블록에서 최소/최대값을 이용한 가역 정보은닉기법 연구)

  • Kim, Woo-Jin;Kim, Pyung-Han;Lee, Joon-Ho;Jung, Ki-Hyun;Yoo, Kee-Young
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.4
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    • pp.69-75
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    • 2014
  • A novel reversible data hiding method using pixel value ordering and prediction error expansion in the sub-block is resented in this paper. For each non-overlapping $2{\times}2$ sub-block, we divide into two groups. In the min group, the lowest value is changed to embed a secret bit and the highest value is changed in the max group. The experimental results show that the proposed method achieves a good visual quality and high capacity. The proposed method can embed 13,900 bits on average, it is higher 4,553 bits than the previous method and the visual quality is maintained 31.39dB on average.