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高中物理“化曲为直”处理非线性实验问题 被引量:4
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作者 马辉 《物理教学探讨(中学教学教研版)》 2012年第5期65-69,共5页
两个非线性的物理量,通过分析对比,找出它们之间的定量关系。可进行各种变数置换,把曲线转换为直线,从而化繁为简、化难为易,解决两个变量之间的定量关系。
关键词 非线性 变数置换 化曲为直 定量关系 物理实验问题
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Contourlet watermarking algorithm based on Arnold scrambling and singular value decomposition 被引量:3
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作者 陈立全 孙晓燕 +1 位作者 卢苗 邵辰 《Journal of Southeast University(English Edition)》 EI CAS 2012年第4期386-391,共6页
A new digital watermarking algorithm based on the contourlet transform is proposed to improve the robustness and anti-attack performances of digital watermarking. The algorithm uses the Arnold scrambling technique and... A new digital watermarking algorithm based on the contourlet transform is proposed to improve the robustness and anti-attack performances of digital watermarking. The algorithm uses the Arnold scrambling technique and the singular value decomposition (SVD) scheme. The Arnold scrambling technique is used to preprocess the watermark, and the SVD scheme is used to find the best suitable hiding points. After the contourlet transform of the carrier image, intermediate frequency sub-bands are decomposed to obtain the singularity values. Then the watermark bits scrambled in the Arnold rules are dispersedly embedded into the selected SVD points. Finally, the inverse contourlet transform is applied to obtain the carrier image with the watermark. In the extraction part, the watermark can be extracted by the semi-blind watermark extracting algorithm. Simulation results show that the proposed algorithm has better hiding and robustness performances than the traditional contourlet watermarking algorithm and the contourlet watermarking algorithm with SVD. Meanwhile, it has good robustness performances when the embedded watermark is attacked by Gaussian noise, salt- and-pepper noise, multiplicative noise, image scaling and image cutting attacks, etc. while security is ensured. 展开更多
关键词 digital watermarking contourlet transform Arnold scrambling singular value decomposition (SVD)
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