To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes th...To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.展开更多
基金the Science Research Plan of Education Office of Shaanxi Province,China under Grant No. 11JK1048Science Research and Development Program Project of Shaanxi Province,China under Grant No. 2011K17-04-01
文摘To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.
