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Mathematical Problems in Engineering
Volume 2012, Article ID 164869, 14 pages
http://dx.doi.org/10.1155/2012/164869
Research Article

Histogram Modification and Wavelet Transform for High Performance Watermarking

1Department of Business Administration, Chung Hua University, Hsinchu 30012, Taiwan
2Department of Electrical Engineering, National Central University, Chungli 32001, Taiwan
3Department of Electronics Engineering, Chung Hua University, Hsinchu 30012, Taiwan
4Department of Computer Science and Information Engineering, National United University, Miaoli 36003, Taiwan

Received 15 September 2012; Accepted 16 October 2012

Academic Editor: Sheng-yong Chen

Copyright © 2012 Ying-Shen Juang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper proposes a reversible watermarking technique for natural images. According to the similarity of neighbor coefficients’ values in wavelet domain, most differences between two adjacent pixels are close to zero. The histogram is built based on these difference statistics. As more peak points can be used for secret data hiding, the hiding capacity is improved compared with those conventional methods. Moreover, as the differences concentricity around zero is improved, the transparency of the host image can be increased. Experimental results and comparison show that the proposed method has both advantages in hiding capacity and transparency.