• Journal of Broadcast Engineering
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• v.6 no.2
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• pp.177-186
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• 2001

A digital watermark Is a perceptually unobtrusive signal embedded in some multimedia asset such as an Image for copyright protection. In many cases watermark detection amounts to thresholding a correlation vague between a watermark and a received image. Watermarking detection schemes can be classified into two types. Type 1 is based on a correlation process that is applied to the difference between an original image and an input Image to be tested. Type 2 is based on a correlation process that is directly applied to an input Image. The type 1 fails to prove the rightful ownership, while type 2 has an advantage in terms of rightful ownership compared with type 1. However, type 2 has a problem that doesnt appear in type 1. The problem is that correlation between a watermark and an original Image to be watermarked is trio significant to be ignored, when it Is normalized by watermarks energy. In this paper, based on the analysis of the correlation, we propose a novel watermarking scheme to minimize the effect and also verify the performance of the proposed scheme by experiments.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.55-63
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• 2010

In this paper, a new video watermarking algorithm using 3D wavelet transform and position encoding of spread spectrum correlation is proposed as a method for ensuring enough payload in order to protect copyright for video contents. This algorithm provides better robustness than other watermarking methods in bit error and rotation because it uses the position encoding and $4{\times}4$ sample space instead of $1{\times}1$ pixel to express a digit. The evaluation result over 6 video clips shows that the PSNR is over 31dB at strength 11 when histogram is narrow and it satisfies the transparency. Also, it shows the robustness of the proposed watermark algorithm that the BER is 0% to three codecs.

• Journal of Korea Multimedia Society
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• v.6 no.4
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• pp.620-629
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• 2003

Fingerprinting schemes are techniques applied to protect the copyright on digital goods. These enable the merchants to identify the source of illegal redistribution. Let us assume the following situations connectedly happen: As a beginning, buyer who bought digital goods illegally distributed it, next the merchant who found it revealed identity of the buyer/traitor, then the goods is illegally distributed again. After this, we describe it as“The second illegal redistribution”. In most of anonymous fingerprinting, upon finding a redistributed copy, a merchant extracts the buyer's secret information from the copy and identifies a traitor using it. Thus the merchant can know the traitor's secret information (digital fingerprints) after identification step. The problem of the second illegal distribution is that there is a possibility of the merchant's fraud and the buyer's abuse: that is a dishonest employee of the merchant might just as well have redistributed the copy as by the buyer, or the merchant as such may want to gain money by wrongly claiming that the buyer illegally distributed it once more. The buyer also can illegally redistribute the copy again. Thus if the copy turns up, one cannot really assign responsibility to one of them. In this paper, we suggest solution of this problem using two-level fingerprinting. As a result, our scheme protects the buyer and the merchant under any conditions in sense that (1) the merchant can obtain means to prove to a third party that the buyer redistributed the copy. (2) the buyer cannot worry about being branded with infamy as a traitor again later if he never distribute it.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.249-257
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• 2010

The emerging ubiquitous environment is improving IT technologies and the popularization of broadband Internet is encouraging creation and sharing of various contents. The contents include the concept of production and circulation of digital information/contents, in forms of characters, codes, voices, sounds, client and videos for being used on the Internet and networks. The contents are widely shared in networks and users can have a wide range of knowledge and gain the freedom of presentation from them. So now users participations are augmented gradually. However, many contents without acquiring agree of copyright are sharing on the Internet, so many problems happen in the manufacturing process of digital contents. To solve this problem, many research projects to limit contents utilization onto legitimate users and to provide secure contents protection and download, are in progress. Therefore, in this paper, we propose a secure D-CAS system (SDCS) which provides security for contents downloading.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.459-465
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• 2009

Digital watermarking is a technique to insert a visually imperceptible information into an image so that the information can be extracted for the purposes of ownership verification or authentication. And watermarking techniques can be classified as either fragile or robust. Robust watermarks are useful for copyright and ownership assertion purposes. They cannot be easily removed and should resist common image manipulation procedures such as rotation, scaling, cropping, etc. On the other hand, fragile watermarks are easily corrupted by any image processing procedure, it can detect any change to an image as well as localizing the areas that have been changed. In this paper, we propose a fragile watermarking algorithm using a special hierarchical structure for integrity verification of image and detection of manipulated location. In the proposed method, the image to be watermarked is divided into blocks in a multi-level hierarchy and calculating block digital signatures in this hierarchy. The proposed method thwarts the cut-and-paste attack and the experimental results to demonstrate the effectiveness of the proposed method.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.212-224
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• 2009

Proliferation of high performance internet infrastructures finally allows their users download a single copy of regular movie just within in a couple of seconds. Ease of accesses to the software for downloading consequently leads them insensitive to the ethics or legitimacy of their conduct. Thus, strong legal action is enforced for piracy over nationally through strengthen the copyright law. We in this paper conducted a survey to see whether netizens prefer to download just for the matter of their convenience. Whilst the level of awareness is addressed even in a far-fetched manner in the area of music piracy and computer software piracy, the case of movie is much different in that we even fail to find any survey that has been made for movie piracy. The survey has been made by devising questionnaires for netizens and it was posted web WorldSurvey, which is the most prominent online survey site in Korea. To our surprise, 9 out of 10 respondents expressed they actually resort to illegal downloading for the reason of convenience. We realized one more surprise. More than 95% of netizens conspicuously aware of their downloading behaviors are mischievous and illegal without reservation.

• 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.

• Journal of Korea Multimedia Society
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• v.3 no.1
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• pp.53-62
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• 2000

Digital watermarking has been considered as an important technique to protect the copyright of digital content. It is essential that a watermark embedded in a still or moving image resists against various attacks ranging from compression, filtering to cropping. In particular, as JPEG is a dominant still image compression standard for Internet applications, digital watermarking methods that are robust against the JPEG compression are especially required. Most digital watermarking methods proposed so far work by modulating pixels/coefficients without considering the quality level of JPEG, which renders watermarks readily removable. In this paper, we proposed a new digital watermarking method as follows. For providing the robustness against JPEG, the quality level of JPEG is used as parameter on watermarking so as to compute the loss of image caused by JPEG compression and we compute the difference of an original image resulted from JPEG compression. Also in proposed method, we compute the visual components that are derived from the information of edge within image and consideration of brightness discrimination which is one of human visual system's properties. Thus, we proposed new watermarking scheme that after constructing a watermark by considering the loss of image resulted from JPEG compression and visual components derived from the human visual system, the watermark is embedded into the image.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1347-1358
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• 2008

A blind video watermarking scheme for providing safety, authenticity, and copyright protection is proposed in this paper, which is robust to MPEG-4 SVC and multimedia transcoding. In proposed method, embedding and detecting of watermark is performed based on base layer with considering spatial SVC. To be robust from temporal SVC, our method embeds repeatedly a permutated character with ordering number per one frame. Also for robustness from multimedia transcoding and FGS, the method is embedded watermark in low middle frequency of each frame adaptively based on DCT in ROI. Through experimental results, invisibility of the watermark is confirmed and robustness of the watermark against the spatial SVC, temporal SVC, FGS and video transcoding between MPEG-2 and MPEG-4 SVC is also verified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.256-268
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• 2007

In this paper, we present a watermarking method for 3-D mesh sequences. The main idea is to transform vertex norm with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle) frequency frames according to watermark bit to be embedded. All vertices are divided into groups, namely bin, using the distribution of coefficients in low frequency frames. As the vertices with the identical connectivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into the wavelet coefficients of vertex norm. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. Through simulations, we show that the proposed is flirty robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.