• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.535-537
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• 2002

본 논문에서는 HVS을 이용하여 웨이브렛기반 이미지 워터마킹 기법을 제안한다. 웨이브렛 변환 된 각 밴드 중 최고 저주파 밴드에 인접한 3개의 밴드를 선택하여 각 밴드에 워터마크를 반복적으로 삽입하여 견고성을 높였다. 또한 밴드 안의 모든 계수 값에 워터마크를 삽입하지 않고 선택적으로 삽입함으로써 비가시성을 고려하였다. 저주파 영역에 워터마크를 삽입함으로서 가우시안 노이즈나 JPEG, 잘라내기 등 여러 공격모델에 대해 견고성을 잘 보여주고 있다.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.213-216
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• 2001

본 논문은 심리음향모델과 주파수변환을 이용하여 MP3 와 AAC 의 압축에서 강인하게 살아남을 수 있는 디지털 오디오 워터마킹 알고리즘에 관한 것이다. 워터마크를 의사난수열이나 이미지 등 외부 정보를 이용하지 않고 원본음악으로부터 생성시킨다는 것이 본 논문의 가장 큰 특징으로 원본 오디오로부터 생성된 워터마크는 음악과 융합되어 워터마크의 삽입여부를 일반인의 청각으로는 인식할 수 없다.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.101-104
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• 2002

This paper proposes a unique data embedding algorithm for the video sequence. It describes two processings: shot boundary detection and robust data embedding. First, for the shot boundary detection, instead of using absolute frame differences, block by block based relative frame differences are employed. Frame adaptive thresholding values are also employed for the better detection. Second, for the robust data embedding, we generate message template and then convolve and correlate it with carrier signal. And then we embed data on the time domain video sequence. By using these two methods, watermarks into randomly selected frames of shots. Watermarks are detected well even if several certain shots are damaged because we embed watermark into each shot equally.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.327-339
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• 2004

In this paper, we propose a new watermark algorithm for halftone images using iterative error minimizing method. In the proposed method, watermark bits are hidden at pseudo-random locations within a halftone image. To remove the distortions due to the inserted watermark bits and increase the invisibility of watermark, an iterative error minimizing technique is used. We define the halftoning error is defined as the difference between the original grayscale image and HVS-filtered printed halftone image. Then we iteratively find the pixel pattern with minimum halftoning error and displace the original pixel pattern with it. In order to be robust to geometrical modification like cropping or rotation, we insert the same watermark periodically into halftone images. Experiments using printed and scanned images show that the proposed method is a robust method to the geometrical modification and to hide the large amount of data within a halftone image without noticeable distortion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1358-1363
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• 2018

As the usage of the Internet grows and digital media become more diversified, it has become much easier for digital contents to be distributed and shared. This makes easier to access the desired digital contents. On the other hand, there is an increasing need to protect the copyright of digital works. There are some prevalent ways to protect ownership, but they accompany several disadvantages. Among those ways, watermarking methods have the advantage of ensuring invisibility, but they also have a disadvantage that they are vulnerable to external attacks such as a noise and signal processing. In this paper, we propose the detecting method of illegal contents that is robust against external attacks to protect digital works. We extract HSV and LBP features from images and use Euclidian-based hashing techniques to shorten the searching time on high-dimensional and near-duplicate videos. According to the results, the proposed method showed higher detection rates than that of the Watermarking techniques in terms of the images with fabrications or deformations.

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.13-20
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• 2001

In this paper, we propose a new digital audio watermarking scheme In the cepstrum domain. We insert a digital watermark signal Into the cepstral components of the audio signal using a technique analogous to spread spectrum Communications, hiding a narrow band signal in a wade band channel. In our proposed method, we use pseudo-random sequences to watermark the audio signal. The watermark Is then weighted in the cepstrum domain according to the distribution of cepstral coefficients and the frequency masking characteristics of the human auditory system. The proposed watermark embedding scheme minimizes audibility of the watermark signal. and the embedded watermark is robust to mu1tip1e watermarks, MPEG audio ceding and additive noose.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.214-217
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• 2003

In this paper, we proposed an efficient blind watermarking algorithm using wavelet transform. The proposed algorithm inserts watermark into the high frequency subbands that were transformed by 1-level wavelet transform of original image. Watermark insertion is achieved by exchanging each the corresponding coefficients in the HL, LH, HH subbands according to be inserted watermark value. And watermark is extracted by the relation of wavelet coefficients without original image. Experimental results demonstrate that watermarked image has a good quality not to be able to be perceptible and is robust various attacks such as JEPG lossy compression, clipping and sharpening.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.1-7
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• 2004

The rapid growth of digital media and communication networks has created an urgent need for self-contained data identification methods to create adequate intellectual property right(IPR) protection technology. In this paper we propose a new watermarking method that could embed the gray-scale watermark logo in low frequency coefficients of discrete wavelet transform(DWT) domain as the marking space by using our Linear Bit-eXpansion(LBX) interleaving of gray-scale watermark, to use lots of watermark information without distortion of watermarked image quality and particularly to be robust against attack which could remove a part of image. Experimental results demonstrated the high robustness in particular against attacks such as image cropping and rotation which could remove a part of image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.602-609
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• 2002

In this paper, we propose an robust invisible watermarking method using wavelet transform and singular value decomposition for the ownership protection. of images. For this method, after we decompose the original image in three level using wavelet transform, we use singular value decomposition based key depended watermark insertion method in the lowest band $LL_3.$ And we also watermark using DCT for extraction of watermark and verification of robustness. In the experiments, we found that it had a good quality and robustness in attack such as compression, image processing, geometric transformation and noises. Especially, we know that this method have very high extraction ratio against nose and JPEG compression. And Digimarc's method can not extract watermark in 80 percent compression ratio of JPEG, but the proposed method can extract well.