• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.81-84
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• 2001

In this paper, we proposed a digital watermarking for color still image using the characteristics of human visual system and the achromatic block information. We use a binary watermark signal and insert watermark signal in the chromatic component region of YCrCb color space. In order to extract the watermark signal, we extracted the watermark signal by presuming that modified pattern of chromatic saturation without using original an image. Experimental results show that the proposed watermarking method has a good performance to embed watermark signal and extract one.

• The KIPS Transactions:PartB
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• v.14B no.5
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• pp.337-342
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• 2007

Multi-level has advantage to express image in all levels with different images. This paper proposes digital watermarking built-in technique to transform color image to YCbCr color space to guarantee robustness and imperceptibility of the watermark in the various expression of color images, and to hide multi-level data which shows spread spectrum from low resolution to whole resolution for the Y-signal of multi-level. In color signal, Y-signal and low resolution built-in watermark has risk to be visible, but it can guarantee the robustness of watermark in various colors and transformed images. As a result of the experiment, wavelet compression image with built-in watermark showed robustness and imperceptibility of watermark.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1946-1953
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• 2006

Because the embedded watermark of luminance component guarantees the extraction of ownership information when the color image is converted to gray scale image, the information of ownership right as to the luminance component is embedded in the luminance-chrominance color space such as YCbCr. Therefore, this paper proposes watermark embedding, extraction and authentication algorithm of color image. which considers the device and performance of multimedia contents service by focusing on the robustness and invisibility of watermark. The color image is converted from RGB color space to YCbCr color space, and then the properties of each component of Y(Luminance), Cb(Color Differences) and Cr(Color Differences) are considered in order to embed, extract and certify multi-level watermark in the frequency domain based on the wavelet. As a result, it can guaranteed the robustness for the JPEG compression and invisibility of watermark for multi-level.

• Proceedings of the IEEK Conference
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• 2003.11a
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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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.792-795
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• 2004

Digital watermarking technology is one of method of protecting property from the illegal reproduction of digital data. This technology inserts the specific data in a certain file to identify the property, that is an author and rights, not for human to be seen and heard. In this paper, the watermarking technology which inserts a RGB rotor watermark in a JPEG2000 color image using the visual characteristics of wavelet coefficient was proposed. After applying various attack at a watermarked image according to proposed technology, the likeness between the original image, the watermark and the extracted watermark was measured and investigated. As a result, the PSNR value of image was varied depending on perceptual parameter, but we can obtain 32㏈ as a whole.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.765-778
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• 2016

In watermarking schemes, the discrete wavelet transform (DWT) is broadly used because its frequency component separation is very useful. Moreover, LU decomposition has little influence on the visual quality of the watermark. Hence, in this paper, a novel blind watermark algorithm is presented based on LU transform and DWT for the copyright protection of digital images. In this algorithm, the color host image is first performed with DWT. Then, the horizontal and vertical diagonal high frequency components are extracted from the wavelet domain, and the sub-images are divided into $4{\times}4$ non-overlapping image blocks. Next, each sub-block is performed with LU decomposition. Finally, the color image watermark is transformed by Arnold permutation, and then it is inserted into the upper triangular matrix. The experimental results imply that this algorithm has good features of invisibility and it is robust against different attacks to a certain degree, such as contrast adjustment, JPEG compression, salt and pepper noise, cropping, and Gaussian noise.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.631-635
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• 2004

The rapid development of digital media and communication network urgently brings about the need of data certification technology to protect IPR (Intellectual property right). This paper proposed a new watermarking method for embedding contents owner's audio signal in order to protect color image IPR. Since this method evolves the existing static model and embeds audio signal of big data, it has the advantage of restoring signal transformed due to attacks. Three basic stages of watermarking include: 1) Encode analogue ID owner's audio signal using PCM and create new 3D audio watermark; 2) Interleave 3D audio watermark by linear bit expansion and 3) Transform Y signal of color image into wavelet and embed interleaved audio watermark in the low frequency band on the transform domain. The results demonstrated that the audio signal embedding in color image proposed in this paper enhanced robustness against lossy JPEG compression, standard image compression and image cropping and rotation which remove a part of image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1755-1759
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• 2004

Digital watermarking technology is one of method of protecting property from the illegal reproduction of digital data. This technology inserts the specific data in a certain file to identify the property, that is an author and rights, not for human to be seen and heard. In this paper, the watermarking technology which inserts a RGB color watermark in a JPEG2000 color image using the visual characteristics of wavelet coefficient was proposed. After applying various attack at a watermarked image according to proposed technology, the likeness between the original image, the watermark and the extracted watermark was measured and investigated. As a result, the PSNR value of image was varied depending on perceptual parameter, but we can obtain 32dB as a whole.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.11-20
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• 2015

Digital watermarking provides electronic means for proving the copyrights of distributed digital media copies. Research on digital watermarking for images is recently directed toward that for color images extensively used in real life, based on the substantial results in digital watermarking for gray-scale images. Color images have multiple channels, each of which corresponds to a gray-scale image. While there are some watermarking techniques for color images that just apply those for gray-scale images to one channel of the color images, the correlation characteristics between the channels are not considered in them. This paper proposes a zero-watermarking technique that makes keys via combining an image dependent watermark, created through comparing two channels of the color image and copyright watermark scrambled. Due to zero-watermarking, it does not change anything of cover(host) images. Watermark images are robust against some common attacks such as sharpening, blurring, JPEG lossy compression, scaling, and cropping.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.701-704
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• 2000

In this paper, we focus on digital watermarking for color images. At first, in order to embed the watermark signal in color image, we converted RGB color space to YCbCr color space which is a world-wide digital component video standard. In addition, we adopted the acceptable degree of color difference in order to keep the invisibility.