• International Journal of Contents
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• 제11권3호
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• pp.39-46
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• 2015

When host images are watermarked with CRT (Chinese Remainder Theorem), the watermark images are still robust in spite of the damage of the host images by maintaining the remainders in an unchanged state within some range of the changes that are incurred by the attacks. This advantage can also be attained by "zero-watermarking," which does not change the host images in any way. This paper proposes an improved zero-watermarking scheme for color images on the DCT (Discrete Cosine Transform) domain that is based on the CRT. In the scheme, RGB images are converted into YCbCr images, and one channel is used for the DCT transformation. A key is then computed from the DC and three low-frequency AC values of each DCT block using the CRT. The key finally becomes the watermark key after it is combined four times with a scrambled watermark image. When watermark images are extracted, each bit is determined by majority voting. This scheme shows that watermark images are robust against a number of common attacks such as sharpening, blurring, JPEG lossy compression, and cropping.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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• pp.1487-1490
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• 2003

This paper shows the watermarking system that inserts copyright holder's logo in music file. In other words, a sound file is able to have an image information like a logo or letters. The watermarking system converts a sound file into an image file using spectrogram. In the spectrogram domain, a logo is inserted using spread spectrum. The proposed technique shows that the verification of copyright is better than the method using PN-Sequence.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권7호
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• pp.487-494
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• 2013

의료 영상 워터마킹은 헬스케어 정보 시스템의 보안 서비스 분야에서 많은 주목을 받고 있다. 본 논문은 워터마킹을 삽입할 최적의 서버 블록 위치 선택을 위한 개선된 퍼지 클러스터링 기법, 이산 웨이블릿 변환 및 이산 코사인 변환을 분할된 회백질 의료 영상에 적용한 블라인드 의료 영상 워터마킹 기법을 제안한다. 모의실험결과, 제안한 워터마킹 기법은 기존의 기법들보다 PSNR과 M-SVD에서 우수한 성능을 보였다. 또한, 제안한 워터마킹 기법은 노이즈 첨가, 필터링, JPEG 압축, 블러링, 히스토그램 균일화, 크로핑과 같은 공격에서도 기존의 기법들보다 정규화된 연관성 값에서 보다 강인함을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1761-1784
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• 2017

In order to improve the embedding rate of reversible watermarking algorithm for digital image and enhance the imperceptibility of the watermarked image, an adaptive reversible image watermarking algorithm based on DE is proposed. By analyzing the traditional DE algorithm and the generalized DE algorithm, an improved difference expansion algorithm is proposed. Through the analysis of image texture features, the improved algorithm is used for embedding and extracting the watermark. At the same time, in order to improve the embedding capacity and visual quality, the improved algorithm is optimized in this paper. Simulation results show that the proposed algorithm can not only achieve the blind extraction, but also significantly heighten the embedded capacity and non-perception. Moreover, compared with similar algorithms, it is easy to implement, and the quality of the watermarked images is high.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2004년도 추계학술대회 학술발표 논문집 제14권 제2호
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• pp.521-524
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• 2004

최근 멀티미디어 기술의 발전 및 인터넷의 보급과 더불어 디지털 데이터가 가지는 복제의 용이성으로 인한 저자자의 소유권 보호와 인증에 대한 문제가 중시되고 있다. 이에 따라 디지털 데이터에 워터 마크를 삽입하여 소유권을 보호하고 데이터의 무결성을 보증하도록 하는 연구가 활발히 진행되고 있다. 본 논문에서는 본 논문에서는 디지털 영상을 주파수 광간으로 변환시킨 후 효과적인 워터마크 삽입을 위해 인간의 감지능력이 떨어지는 주파수 영역과 중요한 주파수 영역을 선택하였다. 그 다음 영상 전체에 반복적이며, 그 내용에 따라 적응적인 워터 마크를 삽입하는 방법을 제시하였다. 주파수 광간으로 변환하는 방법으로는 수직, 수평, 대각선의 3가지 방향성과 다 해상도 (Multi-resolution) 특성을 갖는 웨이블릿 변환을 택하였다. 웨이블릿 기반의 이미지 워터마킹 방법을 LabVIEW의 Machine Vision을 이용하여 지능적인 워터마크를 구현한다.

• 한국멀티미디어학회논문지
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• 제15권7호
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• pp.837-846
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• 2012

본 논문에서는 안전한 웹 맵 매쉬업 서비스 구현을 위한 위성영상의 원근거리 기반의 위성영상 워터마킹 기법을 제안한다. 제안한 방법에서는 위성 영상의 위치 정보와 사용자 정보를 위성 영상의 원근거리에 따라 에지 및 색상 히스토그램 분포에 은닉한다. 따라서 사용자 요구에 의해 서비스되는 임의 해상도의 위성영상들에 대해 해당 해상도의 영상 특성에 적합한 워터마킹 기법을 수행하여 해당위성 영상을 악의적으로 수정하여 불법 유통한 유통자를 추적하고, 사용자의 사생활 보호 할 수 있다. 실험 결과 제안한 기법의 비가시성이 우수함을 확인하고, 회전, 이동 등의 기하학적 공격에도 삽입된 워터마크가 강인함을 확인한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권2호
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• pp.143-147
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• 2007

This paper proposes a new watermarking scheme in which a logo watermark is embedded into the discrete wavelet transform (DWT) domain of the original image using exact radial basis function neural networks (RBF). RBF will learn the characteristics of the image, and then watermark is embedded and extracted by the trained RBF. A watermark is added to the coefficients at the low frequency band of the DWT of an image and a watermark is embedded into the DWT domain using the trained RBF. The trained RBF also used in watermark extracting process. Experimental results show that the proposed method has good imperceptibility and high robustness to common image processing attacks.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.217-220
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• 2003

This paper presents a wavelet-based digital watermarking scheme for color images. We insert watermarks in the DWI domain using spread-spectrum correlation-based watermarking in luminance component of the color image. The watermark, two pseudorandom patterns, is inserted by modifying the wavelet coefficients at subband HL2, LH2, HH2 according to message bits. To detect watermark, we calculate the correlation between the watermarked image and pseudorandom patterns. As compared with correlations, the watermark detector determines embedding message. Experimental results show that the scheme is not only invisible but also robust to various attacks such as JPEG compression, noise addition and so on.

• 한국정보통신학회논문지
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• 제8권7호
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• pp.1488-1492
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• 2004

The digital signal has been replaced the analog signal in most of every field of multimedia including still image, animation, and audio due to the enormous extension of computer supply and the fast development of computer network. The consumers of information are able to enjoy the abundance of information because of one of the digital signal traits that very easy to regenerate the original data. Because of the trait, however, it is very hard for the producers of information to keep the copyright with the merit of original copy in quality excellency. In this paper, the watermarking technology which inserts a RGB color watermark in color image using the visual characteristics of wavelet coefficient was proposed. As a result, the PSNR value of image was varied depending on perceptual parameter, but we can obtain 32dB as a whole.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.902-905
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• 2000

Because of the rapid growth of Internet and multimedia applications, how to protect IPR (intellectual property rights) has become a critical issue. Is one of the ways to overcome the problem of the protection of IPR. Digital watermarking call be applied to multimedia data, such as digital images, digital video, and digital audio. In this paper, we propose a digital watermarking technique for digital images to authenticate an owner or an image by embedding visually recognizable patterns, such as logos, signatures, or stamps into images In BDCT (block discrete cosine transform) frequency domain. The proposed method sorts the components of an original image twice. At the same time, the method, also, rearranges the components of a watermark twice in order to be more robust, and finally embeds the watermark into the image. From the experimental results, the conjunction of three similarity measurements shows that our proposed method is robust to image cropping, image filtering, and JPEG (the Joint Photographic Experts Group) both subjectively and objectively.