• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.49-58
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• 2005

In this paper, we proposed a blind watermarking algerian to use characteristics of a scalar quantizer which is the recommended in the JPEG2000 and JPEG. The proposed algorithm shifts a quantization index according to the value of each watermark bit to prevent losing the watermark information during the compression by quantization. Therefore, the watermark is embedded during the process of quantization, not an additional process for watermarking, and is adaptively applied as a assigned quantizer according application areas. Before embedding process, a LFSR(Linear feedback shift register) rearranged the watermark for the security of the watermark itself and in the embedding process, a LFSR is used to hide the watermarking positions. Therefore the embedded watermark can he extracted by only the owner who knows the initial value of LFSR without the original image. The visual recognizable pattern such as a binary image was used as the watermark. The experimental results showed that the proposed algerian satisfies the robustness and imperceptibility corresponding to the major requirement of watermarking. The results showed the largest error rate to be $5.7\%$ for attack. The experimental result which compares the proposed algorithm with the Mohamed algorithm showed that the proposed algorithm was better than it, exactly $4\~5$ times for the attacks of JPEG and JPEG2000.

• The Journal of the Korea Contents Association
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• v.5 no.2
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• pp.87-94
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• 2005

In this paper, we present a new watermarking algorithm in which a watermark is created based on the energy of the original image and embedded into the image by replacement. The watermark is adjusted to have a certain proportional amount of energy based on one of the original image and embedded into the DFT magnitude component replacing original coefficients. This scheme reduces degree of quality degradation in a watermarked image by maintaining energy and strengthen robustness against attacks by embedding a strong watermark. From the result of experiment, we confirmed that the proposed algorithm had high invisibility of 47.6dB of PSNR and could reconstruct 98.9% of message on average.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1169-1176
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• 2003

In this paper, we propose a blind watermarking that embeds watermarks into wavelet middle frequency subbands using human visual system. Wavelet middle frequency pairs(MFP) show similar distortion against general image processing attacks such as compression and filtering. So the quantization between MFPs is more robust than conventional methods that directly quantize DWT coefficients. We use a noise visibility function(NVF) to obtain a good visual quality This is able to preserve embedding positions after many attacks. Our experimental results show that the proposed scheme is robust to various image processing such as JPEG, while preserving good visual quality above 44㏈.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1C
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• pp.62-67
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• 2008

In this paper, wavelet based blind watermarking using self-reference method is proposed. First, we process wavelet transform of original image. Then, we set all domain except for the low-frequency domain to zero and make self-reference image after wavelet reverse transformation. By choosing specific domain according to the pixel value difference between original image and self-reference image, we make random sequence, use as watermark and embed. The experimental results of the watermark embedding and extraction on various images show that the proposed scheme not only has good image quality, but also has stability on JPEG lossy compression, filtering, sharpening, blurring and noise.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.149-156
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• 2016

We proposed a blind watermarking scheme using singular vectors based on Discrete Wavelet Transform (DWT) and Redundant Discrete Wavelet Transform (RDWT) combined with Singular Value Decomposition (SVD) for copyright protection application. We replaced the 1st left and right singular vectors decomposed from cover image with the corresponding ones from watermark image to overcome the false-positive problem in current watermark systems using SVD. The proposed scheme realized the watermarking system without a false positive problem, and shows high fidelity and robustness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3C
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• pp.398-407
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• 2004

In this paper, a blind watermarking method which is suitable to the video compression using 2-D discrete wavelet transform was proposed and implemented into the hardware using VHDL(VHSIC Hardware Description Language). The goal of the proposed watermarking algorithm is the authentication about the manipulation of the watermark embedded image and the detection of the error positions. Considering the compressed video image, the proposed watermarking scheme is unrelated to the quantization and is able to concurrently embed or extract the watermark. We experimentally verified that the lowest frequency subband(LL4) is not sensitive to the change in the spatial domain, so LL4 subband was selected for the mark space. And the combination of the bitplanes which has the properties of both the minimum degradation of the image and the robustness was chosen as the embedded Point in the mark space in LL4 subband. Since we know the watermark embedded positions and the watermark is embedded by not varying the value but changing the value, the watermark can be extracted without the original image. Also, for the security when exposing the watermark embedded position, we embed the encrypted watermark by the block cipher. The proposed watermark algorithm shows the robustness against the general image manipulation and is easily transplanted into the image or video compressor with the minimal changing in the structure. The designed hardware has 4037 LABs(24％) and 85 ESBs(3％) in APEX20KC EP20K400CF672C7 FPGA of Altera and stably operates in 82MHz clock frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1194-1202
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• 2007

In this paper, we proposed a blind watermarking algorithm to apply to the rapid prototyping system. The 3D mesh model is used in the step of the CAD modeling before the making of the prototype system of the rapid prototyping system. STL type mesh modeling which is used in this system reduces the error of the system and improves the accuracy of the system. In the step of the CAD modeling, some transformations which do not change the model accuracy are used, but some transformations which change the model accuracy are not used because the mesh model error is related to the accuracy of the prototype system. Most watermarking algorithms embedded a specific random noise as the watermark information into the model. These kinds of the algorithms are not proper to the 3D model watermarking. The proposed algorithm can be used for the accurate prototyping system because it does not change the model after the watermark embedding This means it can be used for the copyright marking and the data integrity.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.69-72
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• 2015

본 논문에서는 디지털 영상 컨텐츠의 저작권 보호를 위해 DWT 를 이용하여 강인성(robustness), 비가시성(invisibility), 보안성(security)을 만족하는 blind 워터마킹 방법을 제안한다. 이 방법은 영상정보에 대한 변화를 원본 영상의 특정 부분에 국한하지 않게 하기 위해서, 특정 주파수 성분에 워터마크를 삽입하는 것이 아닌 전체 영상에 워터마크를 삽입하는 방법이다. 이 방법에서 저작권에 대한 판단은 추출한 워터마크 정보를 통합 판단하는 방법을 사용한다. 이 방법은 저작권 보호를 위해 원본 영상을 보관할 필요가 없으며, Gaussian filtering, average filtering, sharpening 의 영상 필터링, JPEG 손실 영상 압축, resizing, 영상 품질 향상을 위한 Contrast 나 histogram equalization 등의 공격에 충분한 강인성을 보여준다.

• The Journal of the Acoustical Society of Korea
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• v.32 no.1
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• pp.71-78
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• 2013

This paper describes a multiple audio watermarking using Quantization Index Modulation (QIM) on frequency phase and magnitude response. Proposed embedding procedure is composed of two stage. At the first stage, the watermark is embedded on the frequency phase response using QIM. In the second stage, the watermark is embedded using adaptive QIM with the step-size that is adaptively determined using the maximum value of the frequency magnitude response of every frame. The watermark is extracted by calculating the Euclidean distance as the blind detection. The proposed method is robust against most of attacks of audio watermark benchmarking. For the Fourier attacks, the proposed method shows over 95% recovery rate.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.1088-1094
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• 2010

Image authentication algorithms have to discriminate forged contents in the various critical fields of military, medical services, digital documents. They must ensure perceptual invisibility and fragility against malicious attacks. It is desirable that watermarking algorithms support sufficient insertion capacity and blind feature. And, high reliable algorithms that can eliminate false-positive and false-negative errors are needed in the watermark extraction process. In this paper, we control coefficients of high frequency band in a DCT domain and compensate brightness histogram for high reliability. As a result, we found that the proposed algorithm guarantee various requirements such as perceptual invisibility with high PSNR values, fragility, high reliability and blind feature. In addition, experiment results show that the proposed algorithm can be used steganographic applications by sufficient capacity of watermark.