• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.12
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• pp.2340-2354
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• 2011

A new and secure image steganographic scheme based on nonuniform discrete Fourier transform (NDFT) is proposed in this paper. First, the chaotic system is introduced to select embedding points randomly in NDFT domain suitable range, and NDFT is implemented on every non-overlapping block of eight consecutive pixels. Second, the secret messages are scrambled by chaotic systems, and embedded into frequency coefficients by quantization method. The stego-image is obtained by inverse NDFT (INDFT). Besides, in order to discriminate tampers, the low frequency wavelet coefficients of 7 most significant bits (MSBs) of the stego-image are converted into the binary sequence after nonuniform scalar quantization. Then the obtained binary sequence is scrambled by the chaotic systems, and embedded into the least significant bit (LSB) of the stego-image. Finally, the watermarked stego-image can be obtained by a new improved LSB steganographic method. The embedded secret messages can be extracted from the watermarked stego-image without the original cover image. Experimental results show the validity of the proposed scheme, and dual statistics attacks are also conducted to indicate the security.

• ETRI Journal
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• v.34 no.3
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• pp.410-420
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• 2012

A series of reversible watermarking technologies have been proposed to increase embedding capacity and the quality of the watermarked image simultaneously. The major skills include difference expansion, histogram shifting, and optimizing embedding order. In this paper, an accurate predictor is proposed to enhance the difference expansion. An efficient sorter is also suggested to find a more desirable embedding order. The payload is differently distributed into two sub-images, split like a chessboard pattern, for better watermarked image quality. Simulation results of the accurate prediction and sorter based on the payload balancing method yield generally better performance over previous methods. The gap is wide, in particular, in low payload for natural images. The peak signal-to-noise ratio improvement is around 2 dB in low payload ranges.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.168-174
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• 2007

In this paper, we propose a reversible watermarking algorithm where an original image can be recovered from the watermarked image. Most watermarking algorithms cause degradation of image quality in original digital contents in the process of embedding watermarks. In the proposed algorithm, the original image can be obtained when the degradation is removed from the watermarked image after extracting watermark information. In the proposed algorithm, we utilize a peak point of image histogram and the location map and modify pixel values slightly to embed data. Because the peak point of image histogram and the location map are employed in this algorithm, there is no need of extra information transmitted to the receiving side. As the locations watermark embedding are identified using the location map, the amount of watermark data can increase through recursive embedding.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.181-185
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• 2005

In this paper, the DWT(Discrete Wavelet Transform) based watermarking method for authentication and detection of image modification was proposed. The proposed algorithm inserts watermark into high frequency domain after 1-level wavelet transform by exchanging wavelet coefficients and embeds the characteristic values of high frequency domain of original image into the LSB part of watermarked image. Therefore, By extracting LSB values and watermark in the high frequency domain from the watermarked image, we can authenticate the image and detect modified positions.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.17-24
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• 2002

In this paper, we propose a new watermarking method using isolation of invalid blocks for image authentication. We embed messages into the high frequency band in the DCT domain because of its imperceptibility and fragility. And we were able to inspect the identity of valid blocks between error corrected original images and watermarked images through experiments. As a result, we found that the watermarked image is enough to extract binary messages. Therefore, the extra information such as the original image or watermark was not necessary in our extracting process. Experiment results show that the proposed method can be used successfully for image authentication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1761-1784
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• 2017

In order to improve the embedding rate of reversible watermarking algorithm for digital image and enhance the imperceptibility of the watermarked image, an adaptive reversible image watermarking algorithm based on DE is proposed. By analyzing the traditional DE algorithm and the generalized DE algorithm, an improved difference expansion algorithm is proposed. Through the analysis of image texture features, the improved algorithm is used for embedding and extracting the watermark. At the same time, in order to improve the embedding capacity and visual quality, the improved algorithm is optimized in this paper. Simulation results show that the proposed algorithm can not only achieve the blind extraction, but also significantly heighten the embedded capacity and non-perception. Moreover, compared with similar algorithms, it is easy to implement, and the quality of the watermarked images is high.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.130-138
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• 2006

In this paper, a new stereo image watermarking scheme based-on adaptive disparity estimation algorithm is proposed. That is, a watermark image is embedded into the right image of a stereo image pair by using the DWT and disparity information is extracted from this watermarked right image and the left image. And then, both of this extracted disparity information and the left image are transmitted to the recipient through the communication channel. At the receiver, the watermarked right image is reconstructed from the received left image and disparity information through an adaptive matching algorithm. a watermark image is finally extracted from this reconstructed right image. From some experiments using CCETT's 'Manege' and 'Friends' images as a stereo image and English alphabet '3DRC' as a watermark image, it is found that the PSNRs of the watermarked image from the reconstructed right images through the adaptive matching algorithm & DWT is improved 2.03 dB, 3.03 dB and robusted against various attacks. These experimental results also suggest a possibility of practical implementation of an adaptive matching also-rithm-based stereo imagewatermarking scheme proposed in this paper.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.466-469
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• 2002

Using intelligent information contained within the speech to identify the specific hidden data in the watermarked multimedia data is considered to be an efficient method to achieve the speech digital watermarking. This paper presents the performance comparison between various types of speech codec in order to determine an appropriate one to be used in digital watermarking applications. In the experiments, the speech signal encoded by four different types of speech codec, namely CELP, GSM, SBC and G.723.1codecs is embedded into a grayscale image, and theirs performance in term of speech recognition are compared. The method for embedding the speech signal into the host data is borrowed from a watermarking method based on the zerotrees of wavelet packet coefficients. To evaluate efficiency of the speech codec used in watermarking applications, the speech signal after being extracted from the attacked watermarked image will be played back to the listeners, and then be justified whether its content is intelligible or not.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.311-314
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• 2002

This paper has been studied a Image watermarking using PN coding operation where frequency band. By using wavelet transformation, This gets high frequency place HH2 where image watermark puts. Also this places that PN code and binary image are operated. And then, this paper has designed image watermarking index process and extract process, watermarked image which are to add noise is able to extract watermark.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.344-352
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• 2001

In this paper, we propose a cross-correlation property and a related technique based on the validity of image block in a public watermarking and we embed messages into the high frequency band in the DCT domain because of its imperceptibility and fragility. As a result, we were able to inspect the identity of valid block between error corrected original images and watermarked images through experiments. And we confirmed the viability of this cross-correlation as an application for future public watermarking.