Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Research Article A Contourlet-Based Image Watermarking Scheme with High Resistance to Removal and Geometrical Attacks | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 540723 13 pages doi 2010 540723 Research Article A Contourlet-Based Image Watermarking Scheme with High Resistance to Removal and Geometrical Attacks Sirvan Khalighi 1 2 Parisa Tirdad 1 and Hamid R. Rabiee2 1 Electical and Computer Engineering Department Islamic Azad University of Qazvin Iran 2AICTC Research Center Department of Computer Engineering Sharif University of Technology Iran Correspondence should be addressed to Sirvan Khalighi khalighi@ Received 16 August 2009 Revised 8 January 2010 Accepted 1 June 2010 Academic Editor Yingzi Du Copyright 2010 Sirvan Khalighi 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. We propose a new nonblind multiresolution watermarking method for still images based on the contourlet transform CT . In our approach the watermark is a grayscale image which is embedded into the highest frequency subband of the host image in its contourlet domain. We demonstrate that in comparison to other methods this method enables us to embed more amounts of data into the directional subbands of the host image without degrading its perceptibility. The experimental results show robustness against several common watermarking attacks such as compression adding noise filtering and geometrical transformations. Since the proposed approach can embed considerable payload while providing good perceptual transparency and resistance to many attacks it is a suitable algorithm for fingerprinting applications. 1. Introduction Recent rapid growth of distributed networks such as Internet enables the users and content providers to access manipulate and distribute digital contents in high volumes. In this situation there is a strong need for techniques to protect the copyright
