• Journal of Korea Multimedia Society
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• v.14 no.11
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• pp.1431-1437
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• 2011

This paper proposes a novel watermarking algorithm that protects digital copyrights and is robust to attacks. Watermarks are embedded in the subband including the significant part of the signal such as a pitch. Generally, the subband containing the pitch has the biggest energy. In order to find this subband, wavelet packet transform is used to decompose the subbands and their energy are calculated. The signal of the selected subbands is transformed in frequency domain using FFT. The watermarks are embedded using QIM for samples higher than a certain threshold. The blind detection uses the Euclidean distance. The proposed method shows less than 5% BER in the audio watermark benchmarking.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.49-56
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• 2003

In this paper, we propose 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 of the corresponding coefficients in the HL, LH, and HH, subbands according to the 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 in terms of imperceptibility and is robust against various attacks.

• Journal of Broadcast Engineering
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• v.6 no.3
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• pp.270-282
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• 2001

This paper Introduces three well-known blind watermarking algorithms in terms of signal processing aspects. Those three methods include correlation-based, echo-hiding, and patchwork algorithms. Those algorithms can be applied either in time-domain (or equivalently spatial-domain) or frequency-domain (or equivalently transform-domain). This paper describes watermark embedding and detection algorithms as well as basic ideas for those watermarking algorithms. In addition, we include some experimental results.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.888-900
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• 2015

This paper proposes a blind watermarking scheme using DWT satisfying robustness, invisibility, and security to protect the ownership of digital image contents. This scheme does not determine any watermarking position by local image information. It rather inserts the watermark information into all the four lowest frequency subbands after transforming the host image by n-level 2-dimensional DWT, depending on, the sizes of the host image and the watermark data. Its watermark insertion methodology uses some weighting factors according to the kind of the subband and its energy level to adjust the invisibility and the robustness of the watermark. This method is experimented for various pixel-value change attacks and geometric attacks with various images having different resolutions and aspect ratios. With the experimental results and by comparing with existing methods, we show that the proposed method has a great deal of general usage with good watermark invisibility and good robustness against attacks.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.801-804
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• 2005

본 논문에서는 Discrete Wavelet Transform(DWT) 기반의 워터마크 알고리즘을 제안하였다. 제안된 방법은 원 이미지를 4 개의 subimages 로 나누고, DWT 후 한 개의 subimage 의 저주파 영역에 워터마크를 삽입하였다. Subsampling 방법을 사용해 원 이미지 없이 워터마크를 추출하였다. 워터마크는 저주파($LL_2$) 영역에 삽입해 외부의 공격에 강인한 성격을 가지도록 하였고, 화질 열화도 줄일 수 있었다. 잘 알려진 이미지에 대한 실험을 통해 본 논문의 알고리즘의 타당성을 입증하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.155-158
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• 2008

In this paper, we propose a novel blind watermarking Method using 2D CAT (Two dimensional cellular automata transform). In our scheme, firstly, we obtain the gateway values to generate a dual-state, dual-coefficients basis function. Secondly, the basis function transforms images into cellular automata space. Lastly, we use the cellular automata transform coefficients to embed random noise watermark in the cover images. The proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values, better security is guaranteed. Moreover, the new 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.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1347-1358
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• 2008

A blind video watermarking scheme for providing safety, authenticity, and copyright protection is proposed in this paper, which is robust to MPEG-4 SVC and multimedia transcoding. In proposed method, embedding and detecting of watermark is performed based on base layer with considering spatial SVC. To be robust from temporal SVC, our method embeds repeatedly a permutated character with ordering number per one frame. Also for robustness from multimedia transcoding and FGS, the method is embedded watermark in low middle frequency of each frame adaptively based on DCT in ROI. Through experimental results, invisibility of the watermark is confirmed and robustness of the watermark against the spatial SVC, temporal SVC, FGS and video transcoding between MPEG-2 and MPEG-4 SVC is also verified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.256-268
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• 2007

In this paper, we present a watermarking method for 3-D mesh sequences. The main idea is to transform vertex norm with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle) frequency frames according to watermark bit to be embedded. All vertices are divided into groups, namely bin, using the distribution of coefficients in low frequency frames. As the vertices with the identical connectivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into the wavelet coefficients of vertex norm. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. Through simulations, we show that the proposed is flirty robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.242-242
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.232-232
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• 2004