Browsing by Author "Li, Ming-Chu"

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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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    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