Browsing by Author "Chang, Chin-Chen"

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    Expert Systems with Applications
    (2011-06-13) Kieu, Duc; Chang, Chin-Chen
    Recently, Zhang and Wang proposed a steganographic scheme by exploiting modification direction (EMD) to embed one secret digit d in the base-(2 × n + 1) notational system into a group of n cover pixels at a time. Therefore, the hiding capacity of the EMD method is log2(2 × n + 1)/n bit per pixel (bpp). In addition, its visual quality is not optimal. To overcome the drawbacks of the EMD method, we propose a novel steganographic scheme by exploiting eight modification directions to hide several secret bits into a cover pixel pair at a time. By this way, the proposed method can achieve various hiding capacities of 1, 2, 3, 4, and 4.5 bpp and good visual qualities of 52.39, 46.75, 40.83, 34.83, and 31.70 dB, respectively. The experimental results show that the proposed method outperforms three recently published works, namely Mielikainen’s, Zhang and Wang’s, and Yang et al.’s methods.
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    A High Stego-image Quality Steganographic Scheme with Reversibility and High Payload Using Multiple Embedding Strategy
    (2011-06-13) Kieu, Duc; Chang, Chin-Chen
    Tian’s method is a breakthrough reversible data embedding scheme with high embedding capacity measured by bits per pixel (bpp) and good visual quality measured by peak signal-to-noise ratio (PSNR). However, the embedding capacity and visual quality of this method can be significantly improved. Thus, we propose a simple reversible steganographic scheme in spatial domain for digital images by using the multiple embedding strategy. The proposed method horizontally and vertically embeds one secret bit into one cover pixel pair. The experimental results show that the proposed reversible steganographic method achieves good visual quality and high embedding capacity. Specifically, with the one-layer embedding, the proposed method can obtain the embedding capacity of more than 0.5 bpp and the PSNR value greater than 54 dB for all test images. Especially, with the five-layer embedding, the proposed method has the embedding capacity of more than 2 bpp and the PSNR value higher than 52 dB for all test images. Therefore, the proposed method surpasses many existing reversible data embedding methods in terms of visual quality and embedding capacity
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    A lossless data embedding technique by joint neighboring coding
    (2011-06-14) Chang, Chin-Chen; Kieu, Duc; Wen-Chuan, Wu
    Information hiding methods are currently exploited by many researchers for various applications. Proposing an efficient and feasible information hiding method is valuable. This paper presents a new reversible information hiding method for vector quantization (VQ)-compressed grayscale images by using joint neighboring coding (JNC) technique. The proposed method embeds secret data by using the difference values between the current VQ-compressed index and left or upper neighboring indices. The experimental results show that the proposed method achieves the best visual quality of reconstructed images compared with the two related works. In addition, the proposed method obtains as high embedding capacity as Lin and Chang's method, followed by Yang et al.'s method. As for execution speed, Yang et al.'s method is fastest, followed by the proposed method, and then Lin and Chang's method. With respect to bit rate, the proposed method has a little higher bit rate in comparison with the two related works.
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    A Novel Information Concealing Method Based on
    (2011-06-14) Wang, Zhi-Hui; Kieu, Duc; Chang, Chin-Chen; Li, Ming-Chu
    A steganographic scheme with a very good visual quality of stego images was proposed by Zhang and Wang. However, the maximum hiding capacity of this method is 1 bit per pixel (bpp). To improve the hiding capacity of Zhang and Wang's method, we propose a steganographic scheme. The proposed method embeds 2K secret digits in the 5-ary notational systems into each group of (2K + 1) cover pixels, where K is a positive integer. Thus, the maximum hiding capacity of the proposed method can approach 2 bpp. The experimental results show that the PSNR values of the proposed method are always higher than 45 dB at the hiding capacity of 1.99 bpp for all test images.
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    Reversible information hiding for VQ indices based on locally adaptive coding
    (2011-06-14) Chang, Chin-Chen; Kieu, Duc; Chou, Yung-Chen
    Steganography is one of protective methods for secret communications over public networks such as the Internet. This paper proposes a novel reversible information hiding method for vector quantization (VQ) compressed images based on locally adaptive coding method. The proposed steganographic method embeds a secret message into VQ indices in an index table during the process of compressing the index table in the block-by-block manner. The experimental results show that, in average, the proposed method achieves the best visual quality of reconstructed images and the best embedding rate compared to two related works. In terms of compression rate and encoding execution time, in average, Yang et al.’s method is the best, followed by our proposed method, and then Lin and Chang’s method.
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    A Sudoku Based Wet Paper Hiding Scheme
    (2011-06-14) Kieu, Duc; Wang, Zhi-Hui; Chang, Chin-Chen; Li, Ming-Chu
    Good image quality and high hiding capacity are two basic requirements of information hiding systems. Technically, it is very challenging to achieve these two factors simultaneously. The purpose of obtaining either high hiding capacity or good image quality are various from application to application. Inspired from the wet paper codes proposed by Fridrich et al., we propose an information hiding scheme for grayscale images. The proposed scheme first uses a secret key to randomly select a subset of pixels from a cover image as dry pixels. Next, the toral automorphism is applied to the cover image to maximize the number of dry pixel pairs. Then, each secret digit in the base-9 numeral system is embedded into one dry pixel pair. The experimental results show that the proposed scheme can achieve good image quality (i.e., PSNR > 46 dB) and flexible hiding capacity. In addition, unauthorized users without knowing the secret key and the secret parameters used for the toral automorphism can not extract the embedded message