• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.9-15
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• 2011

Zero-watermarking is a digital watermarking technique that can escape from data distortion and quality degradation by no watermark insertion into digital images to be watermarked. This paper proposes DCT0CRT, a CRT-based zero-watermarking technique in the domain of DCT. One of the DC and low-frequency AC coefficients of each DCT block chosen in chaotic way from an image is selected by testing whether it satisfies the CRT-based condition matching with the watermark bit to be embedded. Such selection information forms a key to extract the watermark from the watermarked image. Experimental results show that the image quality watermarked by DCT0CRT is better than that watermarked by any other CRT-based watermarking techniques and the inserted watermark is robust against some common attacks such as sharpening, blurring, and JPEG lossy compression.

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.367-372
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• 2003

The existing watermarking techniques for copyright protection of a digital image are fragile in geometric distortion and it is hard to detect whether it was manipulated artificially. In this paper, we proposed the new copyright protection system that can authorize a digital mage and :an embed or extract a robust watermark in a artificial manipulation in order to solve these problems. In a watermarking part, the proposed a watermarking technique embeds a watermark in a phase component after a Complex Wavelet Transform (CWT) with an original image, and a watermark is extracted from an watermarked image by stages. A copyright about an image can be insisted on than a threshold after comparing a correlation of an original watermark with an extracted watermark if large. In an authentication part of a digital image, EZW (Embedded Zerotree Wavelet) is used, and an authentication cord of an watermarked image is generated. An authentication code of an image to have been distribute to is compared with a generated authentication cord, and artificial operation isn´t than a threshold if large. The proposed copyright protection system through performance evaluation display that it was robust in geometric distortion and a artificial operation was able to be detected.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.861-869
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• 2003

The rapid growth of multimedia network systems has caused overflowing illegal copies of digital contents. Among digital contents, watermarking technique can be used to protect ownership about the image. Copyright protection involves the authentication of image ownership and the identification of illegal copies of image. In this paper, a new digital watermarking technique using HVS and adaptive scale factor based on the wavelet transform is proposed to use the binary image watermark. The original image is decomposed by 3-level wavelet transform. It is embedded to baseband and high frequency band. The embedding in the baseband is considered robustness, the embedding in the high frequency band is concerned about HVS and invisibility. The watermarking of a visually recognizable binary image used the HVS and random permutation to protect the copyright. From the experimental results, we confirm that the proposed technique is strong to various attacks such as joint photographic experts ground(JPEG) compression, cropping, collusion, and inversion of lines.

• Digital Contents
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• no.10 s.113
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• pp.104-107
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• 2002

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.77-80
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• 2001

In this paper, we have introduced a new watermarking method using the Discrete Wavelet Transform (DWT). This method has two features. Firstly the trade-off between the quality and the robustness, and between the quality and the capacitance can be controlled. Next, this method use different scheme according to the watermarks. We have also implemented numerical examples for several kinds of attack. It is found that watermarking method in this paper is robust to above attacks.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.257-260
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• 2001

In this paper, we propose a robust audio watermarking method. The proposed watermarking algorithm is composed of a psychoacoustic model to achieve perceptual transparency and spread spectrum technique to embed watermark. The watermark is embedded in each audio frame by adding a perceptually-shaped pseudo-random sequence. We demonstrate the robustness of the watermarking algorithm.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.110-113
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• 2000

In this paper, we consider the problem of digital audio watermarking to robust about compression without original audio data. We specifically address the audio watermarking using BPSK with variable carrier frequency. This technique make audio data embeded watermarking robust with compression attack, for example MPEG, AC-3, etc.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.519-523
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• 1999

본 연구는 디지털 이미지 데이터에 대한 창작자의 저작권 보호 기술인 watermarking 기술을 연구하였다. 저작권 보호를 위한 정보를 invisible watermark로 삽입하였고, watermarking된 칼라 이미지를 데이터 압축, Filtering, cropping 등과 같은 여러가지 외부 공격에 대한 내구성을 실험하였다. invisible watermark를 삽입하기 위하여 변형된 주파수 변환기법을 이용하였으며, 기존의 PRN(pseudo random number) 방법보다 가시성이 뛰어난 이미지 형태의 로고를 삽입하여 저작권에 대한 확증성을 제고하였다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.519-523
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• 1999

본 연구는 디지털 이미지 데이터에 대한 창작자의 저작권 보호 기술인 watermarking 기술을 연구하였다. 저작권 보호를 위한 정보를 invisible watermark로 삽입하였고, watermarking된 칼라 이미지를 데이터 압축, Filtering, cropping 등과 같은 여러 가지 외부 공격에 대한 내구성을 실험하였다. Invisible watermark를 삽입하기 위하여 변형된 주파수 변환기법을 이용하였으며, 기존의 PRN(pseudo random number)방법보다 가시성이 뛰어난 이미지 형태의 로고를 삽입하여 저작권에 대한 확증성을 제고하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.225-228
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• 2005

According to a popularization of the Internet and digital lifestyle, digital watermarks have been proposed for protection of copyrighted multimedia content. In blind watermark detection, which an original image is not provided, robustness against geometric distortion and compression remains challenging. In this paper, we propose a new perceptual blind discrete wavelet transform - discrete Fourier transform (DWT-DFT) composite watermarking scheme that is robust against both general linear transform and JPEG compression. This algorithm constructs an image-dependent watermark in the most significant DWT coefficients, which is determined by using a hierarchical tree structure. Strength of watermark is determined from a just-noticeable difference (JND) profile of a perceptual model. Furthermore, a desired template is inserted into DFT domain of the watermarked image. In new manner, a cross-ratio of four collinear points is used for detecting the template. Experimental results have showed that the proposed scheme is robust against general linear distortion, JPEG compression and various general kinds of attacks in the Stirmark 3.1 watermark evaluation tool.