• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.51-60
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• 2003

The watermarking is the technique that embeds or extracts the certain data without the change of the original data for the copyright protection of the multimedia contents. Watermark-embedded contents must not be distinguished by human's eye and must be robust to the various image processing and the intentional distortions. In this paper, we propose a new watermarking technique applied in the wavelet domain which has both the spatial and frequency information of a image. For both the robustness and the invisibility, the positions for embedding the watermark is selected with the multi-threshold. We search the similarity between highly correlated coefficients in the each subband and decide the mark space after verifying the significance in the specified subband. The similarity is represented by the coefficient difference between the subbands and its distribution is used in the watermark embedding and extracting. The embedded watermark can be extracted without the original image using the relationship of the subbands. By these properties the proposed watermarking algorithm has the invisibility and the robustness to the attacks such as JPEG compression and the general image processing.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.70-76
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• 2003

Digital watermarking is a technique embedding hidden information into multimedia data imperceptibly such as images and sounds. Generally an original image is transformed and coded watermark data is embedded in frequency domain watermarking models. In this paper, We propose a new data embedding method using Fresnel transform. A watermark image is fresnel-transformed and the intensity of transformed pattern is embedded into original image. Our watermarking model has the flexibility In data embedding. It is possible to get many embedding patterns from a single watermark image by using various distance parameters with Fresnel transform. All kinds of image models such af shape, letter and photo ran be used as a watermark data. The watermarking experiments were conducted to show the validity of the proposed method, and the results show that our method has the robustness against lossy compression, filtering and geometric transformation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1723-1729
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• 2016

Digital watermarking is tried to get an optimum tradeoffs between its performance characteristics, robustness, transparency and capacity. This paper is, therefore, suggesting a watermarking technique that builds multiple barcodes in various frequency bands to implement embedded watermarks that is imperceptible and robust against various attacks. Even though a watermark technique with duplicated barcode watermarks embedded in various frequency bands can satisfy robustness as there is high possibility that watermarks embedded in an image remains after various attacks, the duplicated barcode data can weaken imperceptibility. Thus, to satisfy the conflicting characteristic requirements of watermarks, robustness and imperceptibility, different barcode data is embedded in each frequency band. The test shows that ownership authentication with the technique suggested in this thesis does not require specialized hardware, and extracted watermarks can be easily identified through a mobile barcode scanner app, which allows low complexity, low cost and swift identification.

• Journal of Korea Multimedia Society
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• v.4 no.3
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• pp.247-256
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• 2001

Digital watermarking is a copyright protection technique for digital images which embed a code into the digital data so the data is marked. Watermarking techniques previously deal with on-line digital data and have been developed to withstand digital attacks such image processing, compression and geometric transformation. In this paper we propose a novel method of embedding watermarks in printed images. In the proposed algorithm, watermark is embedded in a dithered binary image by comparing the $2\times{2}$ blocks of the counting array is the number of 1 (WHITE) in the $16\times{16}$ blocks of the dithered binary image with predefined reference block pattern, which is generated by watermark values. The proposed algorithm is able to provide more information at a watermark because the proposed algorithm use both '1'and '0' as watermark values. The watermark information is detected by comparing the watermark which is reconstructed from the image which is embedded watermark with the original watermark which is embedded in a binary image. The performance of the proposed algorithm is compared with that of the conventional watermark embedding algorithm for printed images by detecting watermark for scan images.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.2
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• pp.29-36
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• 2003

This paper proposes a new 3D image transmission technique using digital watermarking for compatibility with conventional 2D digital TV. To transmit 3D images effectively, generally, we use image sequence transmission using temporal-spatial redundancy between stereo images. It is difficult for users with conventional digital TV to watch the transmitted 3D image sequence because of effectivity of 3D image compression. To improve such problem, in this paper, we perceive the concealment of new information of digital watermarking and conceal information of the other stereo image into three channels of the reference image. So we can watch the image with 3D TV as well as conventional digital TV when it is decoded.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.615-622
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• 2007

In general, Harris detector is commonly used for finding salient points in watermarking systems using feature points. Harris detector is a kind of combined comer and edge detector which is based on neighboring image data distribution, therefore it has some limitation to find accurate salient points after watermark embedding or any kinds of digital attacks. In this paper, we have used cross reference points which use not data distribution but geometrical structure of a normalized image in order to avoid pointing error caused by the distortion of image data. After normalization, we find cross reference points and take inverse normalization of these points. Next, we construct a group of triangles using tessellation with inversely normalized cross reference points. The watermarks are affine transformed and transformed-watermarks are embedded into not normalized image but original one. Only locations of watermarks are determined on the normalized image. Therefore, we can reduce data loss of watermark which is caused by inverse normalization. As a result, we can detect watermarks with high correlation after several digital attacks.

• Journal of Digital Contents Society
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• v.5 no.4
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• pp.316-320
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• 2004

In this paper, we propose OFDM/QPSK technique for copyright protection of image data to insert watermark. And, we improve performance of restoration watermark by Reed-Solomon coding that robust burst error. In here, we consider several factors about external effect of image over OFDM/QPSK transmission system.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.466-469
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• 2000

In this paper, a watermarking technique for digital images is proposed. In our method, an image is 1-1eve1 wavelet transformed, and then the watermark of a binary stamp is embedded into the baseband. The watermark is embedded by inverting the polarities of the selected coefficient pairs. In the inverting process, we can increase perceptual image quality by finding means and differences of the selected neighboring coefficient pairs, and then adding values, which are inversely proportional to the differences, to the means. The experimental results show that the proposed method has good quality and is robust to JPEG lossy compression and various image processing operations.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.127-130
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• 2007

This paper proposes a new Digital Watermarking based on Wavelet Transform for Color Images. To ensure the security of the watermark, enlarged watermark by applying linear bit expansion is inserted in a given intensity to a low frequency subband of the color image Y band which is Wavelet transformed after the Arnold Transformation. When detecting the presence of watermark, F norm function is applied unlike the existing methods. The experiment results verify that the proposed watermarking technique has outstanding quality in regards to fidelity and robustness.