• Convergence Security Journal
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• v.2 no.1
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• pp.35-47
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• 2002

In this paper, we will provide an overview of the motion picture watermarking techniques. We will see previously proposed algorithms such as compressed domain watermarking, non-compressed domain watermarking and algorithms for realtime applications etc. We will see test results for signature embedding in motion picture. By spread spectrum method, we embed a signature in each frames. The quality of watermarked motion picture is measured by PSNR(peak signal to noise ratio) about several strengths of watermark. In watermark detection the sign of the correlation sum is the estimated embedded signature bits. We will see different mean PSNR with visual shape of the detected signature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1165-1168
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• 2005

This paper proposes an digital image watermarking method based on discrete wavelet transform(DWT) and spatial perceptual properties of human visula system. first, an digital image is transformed by DWT and inserted gaussian watermark into the frequency domain. To increase the robustness and perceptual invisibility of watermark, the proposed algorithm is combined with the characteristics of digital image and human visual system. The proposed method is invisible and blind watermarking which the original image is not required to detect watermarks. Simulation results show that the proposed method is robust to the general attack such as JPEG compression, enhancement, noise, cropping, and filtering etc.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.163-168
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• 2002

본 논문에서는 워터마크의 기본적인 요구사항인 비가시성(invisibility)을 유지하면서 강인함(robustness)을 최대로 하기 위해 워터마크를 삽입할 때 인간시각 특성(Human Visual System, HVS)을 이용한다. 특히, 주파수 마스킹(frequency masking), 공간 마스킹(spatial masking), 그리고 움직임 마스킹(motion masking)을 결합한 전역마스킹(global masking) 기법을 제안한다. 주파수 마스킹은 프레임을 DCT 변환한 후 주파수 민감도 표(frequency sensitivity table)를 이용해 위치 정보를 구한다. 공간 마스킹은 밝기(luminance) 및 윤곽선(edge) 정보를 이용해서 구하며. 움직임 마스킹은 이웃하는 프레임간의 움직임 변화를 이용하여 프레임간의 상관성을 고려한다. 본 논문에서는 키(key) 값에 의해 발생된 랜덤시퀀스와 로고의 배타적 논리합(exclusive OR)에 의해 결합된 워터마크를 전역 마스킹 결과에 따라 압축되지 않은 비디오 프레임에 직접 적용했으며, 실험을 통해 MPEG 부호화 및 재부호화 공격에 대해서 제안한 방법이 강인함을 확인했다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.565-568
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• 2006

In the luminance and chrominance signal, luminance signal creates gray images, and is capable of making each color component compatible with monochrome system. And color components of luminance and chrominance signals are useful to encode or convert the signal because they have low correlation. Each color signal has low correlation statistically, but they are not independent of one another. Therefore, this paper proposes the watermark inserting algorithm for luminance and chrominance signal in the domain of frequency founded on wavelet, considering the interdependent characteristics of color components. Therefore, it can guarantee the robustness and invisible of digital watermark.

• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.74-81
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• 2008

In this paper, adaptive watermarking algorithm which based on fuzzy reasoning and hybrid scheme is presented. To enforce the time and space complexity, hybrid scheme which utilize a color information as well as visual characteristics is also addressed. Proposed approach have double-aim: in first to use the visual characteristics so as to enforce the robustness of watermarking, and in second to select the optimal sub-band which is to be embedded a watermark. One of the principal advantage is that this approach involved the fuzzy inference module which is designed to select an optimal sub-band from the DWT coefficient blocks. In order to demonstrate the effectiveness of proposed algorithm, some numerical experiments of robustness and imperceptibility are evaluated with respect to such attacks as JPEG compression, noise and cropping.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.487-490
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• 2001

With the establishment of the optimized copyright, digital image watermarking technique is demended to identify the owner of a certain image and to avoid the unauthorized distribution of digital image copies. Also, a robust watermarking approach should survive several possible attacks, such as image processing and lossy image compession. The proposed scheme distributes the 256 gray-level signature information in discrete wavelet transform domain of the host image where is very little visible distortion. While much of the privious work used signature data that is a small fraction of th e host images the proposed approach can easily handle gray-scale Images. As the result, stable reconstruction can be obtained even when the images are transformed, JPEG lossy compression or otherwise modified by low-pass filtering operations.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.6
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• pp.32-40
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• 2000

In this paper, we proposed a wavelet-based digital watermarking algorithm using human visual system and subband-adaptive threshold. After the original image is transformed by discrete wavelet transform, the perceptually significant coefficients of the each subband excluding the lowest level subbands are utilized to embed the watermark. To select perceptually significant coefficients for each subband, we use subband-adaptive threshold. For the selected coefficients in the high frequency subbands, the watermark is embedded using HVS. For those of the baseband, the watermark is embedded by conventional embedding method. We tested the performance of the proposed algorithm compared with conventional watermarking algorithm by computer simulation. The experimental results show that the proposed watermarking algorithm is less visible to human eyes and more robust to image compressions, image processings, and geometric transformations than the conventional algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.853-855
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• 2001

본 논문에서는 웨이브릿 변환과 프랙탈 변환을 함께 적용하여 강인하고 효율적인 워터마킹 방법을 제안하였다. 종래의 방법과 같이 프랙탈 변환만을 이용할 경우 강인함에 비하여 속도가 느리다는 단점이 있다. 크기가 큰 원래 이미지를 프랙탈 변환하지 않고 상대적으로 크기가 적은 워터마크 이미지를 프랙탈 변환함으로서 변환에 걸리는 시간을 줄일 수 있다. 또한 웨이브릿 변환 영역에서 임계치에 의해 삽입에 이용할 계수를 선택적으로 사용함으로써 적절한 대역에 삽입하여 시각적인 왜곡을 최소화 할 수 있다.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.98-105
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• 2004

In this paper, we proposed a watermarking algorithm for embedding visually recognizable pattern into the middle-frequency part:; of image. Binary image as watermark is embedded in the LH2, HL2 and HH2 band of wavelet transformed domain for copyright protection of image data. To evaluate robustness of the proposed method, we applied some basic algorithm of image processing such as scaling, filtering, cropping, histogram equalizing and lossy compression(JPEG, gif). As a result of experiment, the proposed method has the good image quality and the high perceptibility of watermark. It was demonstrated by experiments that the proposed algorithm can provide an excellent protection under various attacks.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.2
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• pp.102-108
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• 2005

CIELAB coordinate is represented by one lightness component and two chromaticity components and similar to human visual system. Visual devices such as computer monitor display images using RGB coordinate. We propose a technique for inserting the watermark of visually recognizable mark into the middle frequency domain of image. RGB coordinate image is transformed into CIELAB coordinate, which include the characteristics of Human vision and then a* component is transformed into DFT(Discrete Fourier transform) transform.