• Journal of Internet Computing and Services
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• v.4 no.3
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• pp.39-46
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• 2003

Generally, the existing watermarking techniques for copyright protection of a digital image are fragile in geometric distortion and all watermark extractions need the same time regardless of degree of distortion. In this paper, we propose the incremental watermarking technique that used a Complex Wavelet Transform(CWT) in order to solve these problems. The proposed incremental watermarking technique embeds a watermark in a phase component after a CWT with an original image, and a watermark is extracted from an watermarked image by stages. A watermark owner can insist on copyright of an image after comparing a correlation between the extracted watermark and the original watermark if it is larger than the threshold. Also, the incremental watermark extraction determines the extraction time of a watermark by the level of distortion. The proposed technique through performance evaluation displayed that it was robust in geometric distortion than the existing watermarking technique.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.592-594
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• 2002

일반적으로 디지털 영상에 대한 기존 워터마킹 기법은 기하학적인 왜곡에 허약하다. 본 논문에서는 기하학적인 왜곡에 강건한 워터마킹 기법을 제안한다. 워터마킹 기법은 워터마크의 생성단계 워터마크 삽입단계, 워터마크 추출 단계로 구성된다. 워터마크 생성단계에서는 시각적으로 구별이 가능한 그레이 영상을 워터마크로 사용하며, 워터마크 삽입 단계에서는 원 영상을 콤플렉스 웨이블릿 변환하여 위상 정보에 워터마크를 삽입한다. 그리고 워터마크 추출 단계에서는 워터마크된 영상으로부터 계층적으로 워터마크를 추출하여 자기 상관관계 비교에 의해 워터마크를 추출한다. 실험 결과를 통하여 이동, 크기 변환, 회전과 같은 기하학적인 변형에도 워터마크가 추출되는 것을 볼 수 있다.

• 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.