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Shih-Tung Wu, Kuo-Liang Chung, Yong-Huai Huang and Jung-Gen Wu
Department of Computer Science and Information Engineering
National Taiwan University of Science and Technology
Taipei, 106 Taiwan
E-mail: k.l.chung@mail.ntust.edu.tw
*Department of Computer Science and Information Engineering
National Taiwan Normal University
Taipei, 106 Taiwan
Recently, several algorithms have been developed to hide data in either text images
or halftone images. According to an observation that the number of transitions between
black pixel and white pixel in the halftone image is much larger than that in the text image,
this paper presents a unified min-max transition (MMT) scheme to embed data into
the above two types of images without visual degradation. For text (halftone) images,
data hiding can be performed by modifying the values of pixels to minimize (maximize)
the number of the transitions. Based on our proposed MMT scheme, a unified block- and
MMT-based data hiding (BMMTDH) algorithm is developed for text images, halftone
images, and mixed text/halftone (MTH) images. Experimental results demonstrate that
for MTH images, our proposed BMMTDH algorithm outperforms the previous relevant
algorithms.
Received October 11, 2006; revised January 2 & March 30, 2007; accepted April 26, 2007.
Communicated by Tzong-Chen Wu.
*This research was supported by the National Council of Science of Taiwan, R.O.C. under contract No. NSC
95-2221-E-011-153.