• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1118-1122
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• 2003

In this paper, we propose a new invisible digital watermarking scheme based on wavelet transform using singular value decomposition. Embedding process is started by decomposing the lowest frequency band image with 3${\times}$3 block among which we define the watermark block chosen by a key set; entropy and condition number of the block. A watermark is embedded in the singular values of each watermark blocks. This provides a robust watermarking in lowest possible time-frequency domain. To detect the watermark, we are locally modeling an attack as 3${\times}$3 matrices on the watermark blocks. Combining with the SVD and the attack matrices, we estimate watermark set corresponding to the watermark blocks. In each watermark block, we determine an optimal watermark which is justified by the T-testing. A numerical experiment shows that the proposed watermarking scheme efficiently detects the watermarks from several JPEG attacks.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.257-260
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• 2001

In this paper, we propose a robust audio watermarking method. The proposed watermarking algorithm is composed of a psychoacoustic model to achieve perceptual transparency and spread spectrum technique to embed watermark. The watermark is embedded in each audio frame by adding a perceptually-shaped pseudo-random sequence. We demonstrate the robustness of the watermarking algorithm.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.213-216
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• 2003

In this paper, we propose a digital watermarking method using the spread spectrum techniques in DCT domain. Watermark is embedded in the middle band frequencies of 8$\times$8 DCT block. Therefore, we improve image quality and robustness. Experiment results show that the proposed watermark is robust against various attack.

• Journal of Digital Contents Society
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• v.5 no.2
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• pp.128-132
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• 2004

In this paper, a Fuzzy Inference System(FIS) based watermarking algorithm in Discrete Wavelet Transform(DWT) domain is proposed. A 2D fuzzy inference values, in which the inputs are parameters of the coefficients of the DWT block of the original image and the output is strength of watermark embedded, is devised. The fuzzy inference algorithm guarantees that the watermark to be embedded into the original image adaptively. The experimental results shows that proposed approach is robust to the digital image processing schemes.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.359-362
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• 2002

In this paper, we propose a new feature-based text watermarking for the binary text image. The structure of specific characters from preprocessed text image are modified to embed watermark. Watermark message are embedded and detected by the following method; Hole line disconnect using the connectivity of the character containing a hole, Center line shift using the hole area and Differential encoding using difference of flippable score points. Experimental results show that the proposed method is robust to rotation and scaling distortion.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.243-246
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• 2002

The proliferation of digitized media(audio, image and video) is creating a processing need for copyright enforcement schemes that protect copyright ownership. we argue that a watermark must be placed in perceptually significant components of a signal if it is to be robust to signal distortions and malicious attack. In this paper, RGB coordinate image is transformed into LUV coordinate, it include the characteristics of, Human vision and then the UV component is transformed into NxN block DCT transform. we propose a technique for embedding the watermark of visually recognizable mark into the middle frequency domain of image.

• Journal of Information Technology Applications and Management
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• v.14 no.1
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• pp.137-144
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• 2007

In this paper, we propose a rotation resistant robust logo embedding watermarking technique. Geometric manipulations make the detection process very complex and difficult. Watermark embedding in the normalized image directly suffers from smoothing effect due to the interpolation during the image normalization. This can be avoided by estimating the transform parameters using image normalization angle and moments, instead of embedding in the normalized image. Conventional rotation resistant schemes that use full frame transform. In this paper we adopt DCT and calculate masking using a spatio-frequency localization of the $8{\times}8$ block DCT coefficients. Experimental results show that the proposed algorithm is robust against rotation process.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.231-234
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• 2001

In this paper, we present a robust watermarking technique based on a DCT-domain watermarking approach and an order statistic(OS) filter. The proposed technique inserts one watermark into each of four coefficients within a 2 ${\times}$ 2 block which is scanned on DCT coefficients in the zig-zag ordering from the medium frequency range. The detection algorithm uses an adaptive trimmed mean operator as a local estimator of the embedded watermark to obtain the desired robustness in the presence of additive Gaussian noise and JPEG compression attacks. The performance is analyzed through statistical analysis and numerical experiments. It is shown that the robustness properties against additive noise and JPEG compression attacks are more enhanced than the previous techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9C
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• pp.898-907
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• 2003

In this paper, we propose a new blind watermarking method that embeds a watermark on the lowest wavelet subband coefficients, while most watermarking techniques embed watermarks in the middle frequency range for robustness and fidelity. A new embedding algorithm for watermarking is proposed that embeds a bi-level watermark sequence into randomly selected wavelet coefficients on the lowest subband(LL) using a quantization in order to be robust. Experimental results prove our novel embedding strategy is invisible and good rate-distortion-robustness performance.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.464-468
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• 2001

In this paper, we propose a robust watermarking technique that accepts time scaling, pitch shift, add noise and a lot of lossy compression such as MP3, AAC, WMA. The technique is developed based on digital filtering. Being designed according to critical band of HAS (human auditory system), the digital filters nearly affect audio quality. Furthermore, before implementing digital filtering, wavelet transform decomposes the audio signal into several signals that is composed of specific frequencies. Designed digital filters scan the decomposed signal. The designed digital filter, band-stop filter, distorts and eliminates specific frequencies of audio signals. Watermarking detection can be accomplished by FFT (Fast Fourier Transform). Firstly, segments of audio signal are transformed by FFT. Then, the obtained amplitude spectrum by FFT is summed repeatedly. Finally the watermark detector can find filters used to watermark encoding based on eliminating frequencies. The suggested technique can embed 4bits/s in a robust manner.