tailieunhanh - Báo cáo hóa học: " Research Article Reversible Watermarking Algorithm with Distortion Compensation"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Reversible Watermarking Algorithm with Distortion Compensation | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID316820 12 pages doi 2010 316820 Research Article Reversible Watermarking Algorithm with Distortion Compensation Vasiliy Sachnev 1 Hyoung Joong Kim 2 Sundaram Suresh 3 and Yun Qing Shi4 1 School of Information Communications and Electronic Engineering The Catholic University of Korea Bucheon 420-743 Republic of Korea 2 CIST Korea University Seoul 136-701 Republic of Korea 3 School of Computer Engineering Nanyang Technological University Singapore 639798 4 Department of Electrical and Computer Engineering NJIT Newark NJ 07102 USA Correspondence should be addressed to Hyoung Joong Kim khj-@ Received 8 September 2010 Accepted 14 December 2010 Academic Editor Ling Shao Copyright 2010 Vasiliy Sachnev 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. A novel reversible watermarking algorithm with two-stage data hiding strategy is presented in this paper. The core idea is two-stage data hiding . hiding data twice in a pixel of a cell where the distortion after the first stage of embedding can be rarely removed mostly reduced or hardly increased after the second stage. Note that even the increased distortion is smaller compared to that of other methods under the same conditions. For this purpose we compute lower and upper bounds from ordered neighboring pixels. In the first stage the difference value between a pixel and its corresponding lower bound is used to hide one bit. The distortion can be removed reduced or increased by hiding another bit of data by using a difference value between the upper bound and the modified pixel. For the purpose of controlling capacity and reducing distortion we determine appropriate threshold values. Finally we present an algorithm to handle overflow .