• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.175-180
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• 2012

This paper presents a blind watermark detection scheme for an additive watermark embedding model. The proposed estimation-correlation-based watermark detector first estimates the embedded watermark by exploiting non-Gaussian of the real-world audio signal and the mutual independence between the host-signal and the embedded watermark and then a correlation-based detector is used to determine the presence or the absence of the watermark. For watermark estimation, blind source separation (BSS) based on independent component analysis (ICA) is used. Low watermark-to-signal ratio (WSR) is one of the limitations of blind detection with the additive embedding model. The proposed detector uses two-stage processing to improve the WSR at the blind detector; the first stage removes the audio spectrum from the watermarked audio signal using linear predictive (LP) filtering and the second stage uses the resulting residue from the LP filtering stage to estimate the embedded watermark using BSS based on ICA. Simulation results show that the proposed detector performs significantly better than existing estimation-correlationbased detection schemes.

• 전기학회논문지
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• 제57권12호
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• pp.2330-2335
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• 2008

In this paper, we proposed a robust watermark scheme for image based on the discrete wavelet transform. In the first, we use the triplet method for embedding and extraction of watermark. Triplet method uses relationship among the discrete wavelet coefficients at the same position in the three detail subband of image. In the second, we use barcode Pattern Image for watermark scheme. By using barcode Pattern Images, a user is able to make many kinds of own watermark. In the third, the proposed method for image watermark provides the invisiblility which the other user can not discriminate watermark from watermarked image. The advantage of the proposed method is visibility when we extracted watermark from the image. The corresponding experimental results show that the proposed method has performance of a robustness from the noise attack.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.181-183
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• 2003

We propose a new watermarking scheme that can be used to embed multiple bits and also resilient to JPEG compression and geometrical transforms such as scaling, rotation, and cropping, based on off-axis holographic watermark that allows multiple watermark recovery without original content(cover image). The holographic watermark is that Fourier transformed digital hologram is embedded into cover image in the spatial domain. The proposed method has not only increased robustness with a stronger embedding but also imperceptibility of the watermark in the evaluation process.

• 융합신호처리학회논문지
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• 제12권3호
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• pp.176-180
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• 2011

Even though algorithms for watermark embedding and extraction step are important issue for digital watermarking, watermark selection and post-processing can give us an opportunity to improve our algorithms and achieve higher performance. For this reason, we summarized the possibilities of improvements for digital watermarking by referring to the watermark merging techniques rather than embedding and extraction algorithms in this paper. We chose Cox's function as main embedding and extraction algorithm, and multiple barcode watermarks as a watermark. Each bit of the multiple copies of barcode watermark was embedded into a gray-scale image with Cox's embedding function. After extracting the numbers of watermark, we applied the watermark merging techniques; including the simple merging, N-step iterated merging, recover merging and combination of iterated-recover merging. Main consequence of our paper was the fact of finding out how multiple barcode watermarks and merging techniques can give us opportunities to improve the performance of algorithm.

• 한국멀티미디어학회논문지
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• 제8권6호
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• pp.783-789
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• 2005

This paper is proposed a watermarking technique for copyright protection of multimedia contents. We proposed adaptive watermark detection algorithm using stochastic perceptual model and statistical decision method in DMWT(discrete multi wavelet transform) domain. The stochastic perceptual model calculates NVF(noise visibility function) based on statistical characteristic in the DMWT. Watermark detection algorithm used the likelihood ratio depend on Bayes' decision theory by reliable detection measure and Neyman-Pearson criterion. To reduce visual artifact of image, in this paper, adaptively decide the embedding number of watermark based on DMWT, and then the watermark embedding strength differently at edge and texture region and flat region embedded when watermark embedding minimize distortion of image. In experiment results, the proposed statistical decision method based on multiwavelet domain could decide watermark detection.

• 전기학회논문지
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• 제58권5호
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• pp.1041-1046
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• 2009

In this paper, we proposed a robust watermark scheme for image based on SVD(Singular Value Transform) and Triplet. First, the original image is decomposed by using 3-level DWT, and then used the singular values changed for embedding and extracting of the watermark sequence in LL3 band. Since the matrix of singular values is not easily altered with various signal processing noises, the embedded watermark sequence has the ability to withstand various signal processing noise attacks. Nevertheless, this method does not guarantee geometric transformation(such as rotation, cropping, etc.) because the geometric transformation changes the matrix size. In this case, the watermark sequence cannot be extracted. To compensate for the above weaknesses, a method which uses the triplet for embedding a barcode image watermark in the middle of frequency band is proposed. In order to generate the barcode image watermark, the pattern of the watermark sequence embedded in a LL3 band is used. According to this method, the watermark information can be extracted from attacked images.

• International Journal of Internet, Broadcasting and Communication
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• 제14권1호
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• pp.116-121
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• 2022

In this paper, we propose a highly secure watermarking technique in which the watermark is multi-encrypted using the R, G, and B component pixels of color image, and then the multi-encrypted watermark is hidden in the LSB of the color image pixel. According to the technique proposed in this paper, the quality of the stego-image created by hiding the multi-encrypted watermark in the LSB of the color image is so excellent that the difference from the cover image cannot be recognized. Also, it is possible to extract the original watermark from the stego-image without loss. If the watermark is hidden in the image using the proposed technique, the security of the watermark is maintained very well because the watermark hidden in the stego-image is multi-encrypted. The proposed watermarking technique can be used in the applications such as military and intellectual property protection requiring high security.

• 한국전자통신학회논문지
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• 제5권5호
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• pp.465-470
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• 2010

본 논문에서는 MPEG2 부호화기내에서 삽입된 워터마크(watermark)의 비트 검출율에 따라 워터마크의 삽입 세기를 적응적으로 조절하는 방법을 제안한다. MPEG2 부호화내에서 워터마크를 삽입하고, 움직임 보상을 위해 복호화한 프레임에서 추출한 워터마크의 BER(bit error rate) 값에 따라 워터마크 세기를 적응적으로 조절한다. 워터마크의 각 비트는 주파수 확산방식을 사용하여 삽입한다. 워터마크 검출은 MPEG2 복호화시에 주파수 영역에서 실시간으로 검출한다. 실험 결과, PSNR(peak signal to noise ratio)은 고정적인 워터마크 세기를 적용한 경우 31.5dB, 가변적 워터마크 세기를 적용한 경우 33.0dB이다. 평균 BER은 0.126으로 허용 한계치 0.2보다 작다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.167-170
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• 2006

본 논문에서는 선형계수확장 기반의 웨이블릿 워터마킹 기법을 제안하였다. 워터마크의 안정성을 위하여 먼저 워터마크에 대하여 Amold 변환을 진행한다. 다음 워터마크와 원 영상에 웨이블릿 변환을 진행한다. 워터마크의 크기를 원 영상의 1/4 정도로 선택하였기 때문에 선형계수확장을 적용하여 워터마크를 원 영상 크기만큼 확대한다. 마지막으로 본 논문에서 제안한 웨이블릿 변환된 영상의 저주파대에 일정한 강도로 워터마크를 삽입한다. 워터마크의 추출 시에 기존 방법과 달리 F 노름(norm) 함수를 적용하여 추출된 워터마크와 원 워터마크의 유사도를 비교한다.

• 한국정보전자통신기술학회논문지
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• 제13권6호
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• pp.503-510
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• 2020

본 논문에서는 다중으로 암호화한 워터마크를 영상 픽셀의 LSB에 은닉하여 워터마크의 보안성을 크게 향상시키는 효과적인 기법을 제안하였다. 영상 픽셀의 LSB에 은닉되어 있는 다중 암호화된 워터마크를 추출하여도 이를 해독하는 것이 불가능하기 때문에 워터마크의 보안성이 매우 높게 유지된다. 제안된 기법을 사용하여 워터마크를 다중으로 암호화하여 영상에 은닉하면, 워터마크가 은닉된 영상의 시각적 화질이 매우 높아 원본 영상과 워터마크가 은닉된 결과 영상의 구별이 불가능하다. 워터마크를 다중으로 암호화하여 원본 영상에 은닉한 결과 영상으로부터, 제안 기법의 절차를 따라 원본 워터마크 데이터를 손실 없이 온전히 추출할 수 있다. 제안된 기법의 성능을 수학적으로 분석하고 제안된 기법의 우수성을 실험을 통하여 확인하였다. 제안된 기법은 기존의 기법에 비하여 영상에 은닉된 워터마크의 보안성을 크게 향상시킨 우수한 영상 워터마킹 기법이다.