• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4389-4411
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• 2018

High dynamic range (HDR) images are becoming pervasive due to capturing or rendering of a wider range of luminance, but their special display equipment is difficult to be popularized because of high cost and technological problem. Thus, HDR images must be adapted to the conventional display devices by applying tone mapping (TM) operation, which puts forward higher requirements for intellectual property protection of HDR images. As the robustness presents regional diversity in the low dynamic range (LDR) watermarked image after TM, which is different from the traditional watermarking technologies, a concept of watermarking activity is defined and used to distinguish the essential distinction of watermarking between LDR image and HDR image in this paper. Then, a novel robust HDR image watermarking algorithm is proposed against TM operations. Firstly, based on the hybrid processing of redundant discrete wavelet transform and singular value decomposition, the watermark is embedded by modifying the structure information of the HDR image. Distinguished from LDR image watermarking, the high embedding strength can cause more obvious distortion in the high brightness regions of HDR image than the low brightness regions. Thus, a perceptual brightness mask with low complexity is designed to improve the imperceptibility further. Experimental results show that the proposed algorithm is robust to the existing TM operations, with taking into account the imperceptibility and embedded capacity, which is superior to the current state-of-art HDR image watermarking algorithms.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.19-22
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• 2000

In this paper, we propose a watermarking method for still images using Discrete Cosine Transform (DCT). Watermarking is a copyright protection technique for digital contents by hiding secret information into the contents. The proposed method embeds the watermark information into DCT coefficients. To obtain a watermarked image that is not only high quality but also has robustness for compression, we considered a method to change the degree of embedding by utilizing the activity of each DCT block. The simulation results show that the proposed scheme can obtain huh quality watermarked images and we can extract most of the embedded data even if they are compressed by JPEG scheme.

• 인터넷정보학회논문지
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• 제4권5호
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• pp.21-29
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• 2003

최근에 멀티미디어 콘텐츠의 전송이 활성화 되고 있다. 이는 인터넷을 통하여 배포되는 멀티미디어 콘텐츠가 상업성을 갖게되는 발판이 되었다. 그러나, 이러한 멀티미디어 컨텐츠는 복사가 자유롭기 때문에 워터마킹 기법만 사용하는 경우에는 상업적으로 사용되기에 많은 취약성을 가지고 있다. 따라서 본 논문에서는 스테가노그래피 기법을 이용하여 멀티미디어 콘텐츠를 보호하기 위한 안전한 DRM 시스템을 제안한다. 본 DRM 시스템은 워터마킹 기술과 스테가노그래피 기술의 특이점을 보강하여 일반적인 DRM 시스템보다 더 강력하다. 따라서, 본 시스템을 통하여 사용자 인증 뿐만 아니라 멀티미디어 콘텐츠의 불법복제 및 불법도용을 방지할 수 있다.