• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.348-351
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• 2002

Recently, the medical imaging field has been digitalized by the development of computer science and digitization of the medical devices. There are needs of the medical imaging database service and long term storage today because of the installation of PACS system following DICOM standards, telemedicine and etc. and ,also, the illegal distortion of the medical information, data authentication and copyright are being happened. In this paper, we propose watermarking technique as a method which can protect private informations and medical imaging from geometric distortion. Because many watermarks for images are sensitive to geometric distortion, we present a algorithm that is insensitive to RST distortion in medical image. we observed the robustness against several of the signal processing and attacks in medical imaging field by embedding watermark after making a region which is insensitive to RST distortion by using FFT and LPM transformation.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.479-484
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• 2003

We propose a blind watermarking method that embeds a binary pseudo-random sequence (watermarks), (-1, 1), into wavelet dc components, while most watermarking techniques embed watermarks in the middle frequency range for robustness and fidelity. In our scheme, the watermarks are embedded into particular locations to be selected by a key, where some watermark embeddings are skipped to avoid severe degradation in quality. Our robustness is compared to some results registered to the ChechMark [1] that is one of the most popular benchmarking tools.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.625-628
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• 2002

디지틸워터마킹은 디지털콘텐츠의 저작권보호 솔루션으로서 현재 주로 이미지, 오디오, 비디오, 텍스트 등을 대상으로 연구되고 있다. 컴퓨터 하드웨어, 네트워크, 그리고, 응용 소프트웨어의 빠른 발전과 함께 국가 차원의 초고속 통신망의 인프라 구축에 힘입어, 3차원 폴리곤과 곡선 및 곡면에 대한 디지털워터마킹에 관심이 높아지고 있다. 본 논문에서는 유리 베지에곡선에 대한 디지털워터마킹에 대한 하나의 방법을 제시한다. 기존의 베지에곡선의 차수를 증가시키는 일반적인 방법이 아닌 유리항의 분모와 분자에 공통의 다항식을 곱하여 차수를 증가시킨다. 이때 공통으로 칠하는 다항식의 관들의 복비(cross ratio) 값에 우리가 숨기고자하는 마크를 삽입하고, 추출해내는 방법을 제시한다. 본 논문에서 제시된 알고리듬은 워터마크를 삽입하는 과정에서 곡선의 형태를 전혀 변화시키지 않는 형태 유지성(shape preserving property)을 갖는다. 또한. 본 알고리듬의 다른 중요한 특징은 곡선이 CAD 시스템에 의해 이용되는 과정에서 흔히 일어나는 재매개화 방법 중 뫼비우스 변환을 이용한 재매개화에 저항성이 있는 알고리듬이라는 것이다. 마지막으로 본 연구에서 제시한 방범에 의한 예제의 결과를 보여준다.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.362-370
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• 2013

In this paper, we propose a novel optical implementation of a 3DES algorithm based on dual XOR logic operations for a cryptographic system. In the schematic architecture, the optical 3DES system consists of dual XOR logic operations, where XOR logic operation is implemented by using a free-space interconnected optical logic gate method. The main point in the proposed 3DES method is to make a higher secure cryptosystem, which is acquired by encrypting an individual private key separately, and this encrypted private key is used to decrypt the plain text from the cipher text. Schematically, the proposed optical configuration of this cryptosystem can be used for the decryption process as well. The major advantage of this optical method is that vast 2-D data can be processed in parallel very quickly regardless of data size. The proposed scheme can be applied to watermark authentication and can also be applied to the OTP encryption if every different private key is created and used for encryption only once. When a security key has data of $512{\times}256$ pixels in size, our proposed method performs 2,048 DES blocks or 1,024 3DES blocks cipher in this paper. Besides, because the key length is equal to $512{\times}256$ bits, $2^{512{\times}256}$ attempts are required to find the correct key. Numerical simulations show the results to be carried out encryption and decryption successfully with the proposed 3DES algorithm.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.66-72
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• 2004

Beyond the digital world from the analog age, the contents are very easily copied under the illegal conditions and these are rapidly distributed by the information super highway. The increase of ilegal usage and conflict in digital content market would diminish motivation of creators for their work, furthermore break down digital content market on cyberspace. Watermarking technology support to the legal users by the protection technique based chi the digital content copyright protection method(DRM). Most of previous digital watermarking have embeded to the content. In this paper, we have researched the standardization of digital rights management and developed more efficient watermark embedding method.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.61-65
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• 2003

In this paper, a novel watermarking technique that based on wavelet packet transform using PIM is proposed for the copyright of the digital images. We divide wavelet packet coefficients into detailed blocks and calculate the complexity of each block using PIM. Because human is impervious to the change in the complex area, the embedding watermark to the selected coefficients using PIM enhances invisibility. From the experimental results, the proposed algorithm shows better invisibility and robustness performance in a general signal processing such as JPEG and SPIHT lossy compression, median filtering. Especially, it demonstrates better performance for the low bit-rate compression in the images that include many high frequency components.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.105-112
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• 2009

In this paper, we propose a digital watermarking method using Multi-resolution Characteristic of 2D CAT (2D cellular automata transform). Firstly, we select the gateway values to generate a basis function and the basis function transforms images into cellular automata space. Then, we embed the random bit sequence as watermark in specific parts of cellular automata transform coefficients. The proposed method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness. Moreover, the proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values.

• The KIPS Transactions:PartB
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• v.12B no.2 s.98
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• pp.151-156
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• 2005

In this paper, we propose feature based character watermarking methods based on geometical features specific to characters of text in document image. The proposed methods can satisfy both data capacity and robustness simultaneously while none of the conventional methods can. According to the characteristics of characters, watermark can be embed or detected through changes of connectivity of the characters, differences of characteristics of edge pixels or changes of area of holes. Experimental results show that our identification techniques are very robust to distortion and have high data capacity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.144-148
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• 2004

Beyond the digital world from the analog age, the contents are very easily copied under the illegal conditions and these are rapidly distributed by the information super highway. The increase of illegal usage and conflict in digital content market would diminish motivation of creators for their work, furthermore break down digital content market on cyberspace. Watermarking technology support to the legal users by the protection technique based on the digital content copyright protection method(DRM). Most of previous digital watermarking have embeded to the content. In this paper, we researched the standardization of digital rights management and developed more efficient watermark embedding method.

• Journal of radiological science and technology
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• v.27 no.2
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• pp.13-19
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• 2004

This study proposes how to insert a strong watermark creating a big change in the areas of edge and texture. While conversion by existing Fourier transformation can acquire information for all ranges of frequency domain from the image, Wavelet transformation can manipulate edge and texture area selectively. Therefore, through wavelet transformation concerned area may be selected and watermarks in copyright formation are inserted. Our proposed algorithm was compared to Xia's watermarking technique using wavelet transformation. Its fidelity and robustness were tested with attack methods used in existing papers and it turns out that the proposed algorithm using HVS properties is more superior to Xia's techniques.